Merge lp:~donadigo/appcenter/code-improvements into lp:~elementary-apps/appcenter/appcenter

[Adam Bieńkowski]

* Fix code style issues
* Improve code readability
* Performance improvements (caching)
* Less hardcoded parts of the code
* Changed some of the member's naming to be simpler
* More GObject's construct {} oriented codebase

This branch makes some general improvements to all components of the code including:

* Fix code style issues
* Improve code readability
* Performance improvements (caching)
* Less hardcoded parts of the code
* Changed some of the member's naming to be simpler
* More GObject's construct {} oriented codebase

[Rico Tzschichholz (ricotz)]

Split this is up in consistent commits/branches

review: Disapprove

Unmerged revisions

324. By Adam Bieńkowski on 2016-10-13

Some last minute changes

323. By Adam Bieńkowski on 2016-10-13

Bring back needed parts of activate method

322. By Adam Bieńkowski on 2016-10-13

Align if statement

321. By Adam Bieńkowski on 2016-10-13

Some improvements made to the entire code of appcenter

=== modified file 'src/AbstractAppContainer.vala'
--- src/AbstractAppContainer.vala	2016-09-17 18:18:04 +0000
+++ src/AbstractAppContainer.vala	2016-10-13 21:30:22 +0000
@@ -1,6 +1,7 @@
 namespace AppCenter {
     public abstract class AbstractAppContainer : Gtk.Grid {
-        public AppCenterCore.Package package;
+        public AppCenterCore.Package package { get; construct; }
+        public uint icon_size { get; construct; default = 48; }
 
         protected Gtk.Image image;
         protected Gtk.Label package_name;
@@ -46,16 +47,14 @@
         }
 
         construct {
-            image = new Gtk.Image ();
-
             progress_bar = new Gtk.ProgressBar ();
             progress_bar.show_text = true;
             progress_bar.valign = Gtk.Align.CENTER;
+            
             /* Request a width large enough for the longest text to stop width of
              * progress bar jumping around */
             progress_bar.width_request = 350;
-            progress_bar.no_show_all = true;
-            progress_bar.hide ();
+            set_widget_visible (progress_bar, false);
 
             action_button_group = new Gtk.SizeGroup (Gtk.SizeGroupMode.BOTH);
 
@@ -65,7 +64,7 @@
             action_button = new Widgets.AppActionButton (_("Install"));
             action_button.clicked.connect (() => action_clicked.begin ());
 
-            uninstall_button = new Widgets.AppActionButton (_("Uninstall"));
+            uninstall_button = new Widgets.AppActionButton (_("Uninstall"), Gtk.STYLE_CLASS_DESTRUCTIVE_ACTION);
             uninstall_button.clicked.connect (() => uninstall_clicked.begin ());
 
             var button_grid = new Gtk.Grid ();
@@ -92,17 +91,20 @@
 
             action_stack.add_named (button_grid, "buttons");
             action_stack.add_named (progress_grid, "progress");
-        }
 
-        protected virtual void set_up_package (uint icon_size = 48) {
+            package_name = new Gtk.Label (null);
             package_name.label = package.get_name ();
+
+            package_summary = new Gtk.Label (null);
             package_summary.label = package.get_summary ();
             package_summary.ellipsize = Pango.EllipsizeMode.END;
+
+            image = new Gtk.Image ();
             image.gicon = package.get_icon (icon_size);
 
+            package.change_information.bind_property ("can-cancel", cancel_button, "sensitive", GLib.BindingFlags.SYNC_CREATE);
+
             package.notify["state"].connect (update_state);
-
-            package.change_information.bind_property ("can-cancel", cancel_button, "sensitive", GLib.BindingFlags.SYNC_CREATE);
             package.change_information.progress_changed.connect (update_progress);
             package.change_information.status_changed.connect (update_progress_status);
 
@@ -116,36 +118,23 @@
         }
 
         protected void update_action (bool show_uninstall = true) {
-            uninstall_button.no_show_all = true;
-            uninstall_button.hide ();
-            progress_bar.no_show_all = true;
-            progress_bar.hide ();
-            action_stack.no_show_all = false;
-            action_stack.show_all ();
+            set_widget_visible (uninstall_button, false);
+            set_widget_visible (progress_bar, false);
+            set_widget_visible (action_stack, true);
             action_stack.set_visible_child_name ("buttons");
 
             switch (package.state) {
                 case AppCenterCore.Package.State.NOT_INSTALLED:
                     action_button.label = _("Install");
-                    action_button.no_show_all = false;
-                    action_button.show ();
+                    set_widget_visible (action_button, true);
                     break;
 
                 case AppCenterCore.Package.State.INSTALLED:
                     if (show_uninstall) {
-                        /* Uninstall button will show */
-                        action_button.label = "Not visible";
-                        action_button.no_show_all = true;
-                        action_button.hide ();
-
-                        if (!is_os_updates) {
-                            uninstall_button.no_show_all = false;
-                            uninstall_button.show_all ();
-                        }
+                        set_widget_visible (action_button, false);
+                        set_widget_visible (uninstall_button, !is_os_updates);
                     } else {
-                        /* No Uninstall action in list view */
-                        action_stack.no_show_all = true;
-                        action_stack.hide ();
+                        set_widget_visible (action_stack, false);
                     }
 
                     break;
@@ -157,22 +146,22 @@
                 case AppCenterCore.Package.State.INSTALLING:
                 case AppCenterCore.Package.State.UPDATING:
                 case AppCenterCore.Package.State.REMOVING:
-                    progress_bar.no_show_all = false;
-                    progress_bar.show ();
+                    set_widget_visible (progress_bar, true);
                     action_stack.set_visible_child_name ("progress");
                     break;
 
                 default:
-                    assert_not_reached ();
+                    break;
             }
         }
 
         protected void update_progress () {
-             progress_bar.fraction = package.progress;
-         }
+            progress_bar.fraction = package.progress;
+        }
 
         protected void update_progress_status () {
             progress_bar.text = package.get_progress_description ();
+
             /* Ensure progress bar shows complete to match status (lp:1606902) */
             if (package.changes_finished) {
                 progress_bar.fraction = 1.0f;
@@ -185,11 +174,11 @@
         }
 
         private async void action_clicked () {
-             if (package.update_available) {
-                 yield package.update ();
+            if (package.update_available) {
+                yield package.update ();
             } else if (yield package.install ()) {
-                 // Add this app to the Installed Apps View
-                 MainWindow.installed_view.add_app.begin (package);
+                // Add this app to the Installed Apps View
+                MainWindow.installed_view.add_app.begin (package);
                 update_state ();
             }
         }

=== modified file 'src/AbstractAppList.vala'
--- src/AbstractAppList.vala	2016-09-14 16:58:13 +0000
+++ src/AbstractAppList.vala	2016-10-13 21:30:22 +0000
@@ -27,6 +27,7 @@
 
         construct {
             hscrollbar_policy = Gtk.PolicyType.NEVER;
+
             var alert_view = new Granite.Widgets.AlertView (_("No Results"), _("No apps could be found. Try changing search terms."), "edit-find-symbolic");
             alert_view.show_all ();
             list_box = new Gtk.ListBox ();
@@ -38,15 +39,18 @@
                 var row = (Widgets.AppListRow)r;
                 show_app (row.get_package ());
             });
+            
             add (list_box);
 
             action_button_group = new Gtk.SizeGroup (Gtk.SizeGroupMode.BOTH);
         }
 
         public virtual void add_package (AppCenterCore.Package package) {
-            var row = make_row (package);
-            set_up_row (row);
-            after_add_remove_change_row ();
+            var row = create_row (package);
+            row.show_all ();
+            list_box.add (row);
+            row.get_package ().changing.connect (on_package_changing);
+            list_changed ();
         }
 
         public void remove_package (AppCenterCore.Package package) {
@@ -56,12 +60,14 @@
                 if (!row.has_package ()) {
                     continue;
                 }
+
                 if (row.get_package () == package) {
                     row.destroy ();
                     break;
                 }
             }
-            after_add_remove_change_row ();
+
+            list_changed ();
         }
 
         public void clear () {
@@ -72,33 +78,33 @@
                     package.changing.disconnect (on_package_changing);
                     row.destroy ();
                 }
-            };
-        }
-
-        protected abstract Widgets.AppListRow make_row (AppCenterCore.Package package); // {
-
-        protected virtual void set_up_row (Widgets.AppListRow row) {
-            row.show_all ();
-            list_box.add (row);
-            row.get_package ().changing.connect (on_package_changing);
-        }
-
-        protected virtual void after_add_remove_change_row () {}
+            }
+        }
+
+        protected abstract Widgets.AppListRow create_row (AppCenterCore.Package package);
+
+        protected virtual void list_changed () {
+            
+        }
 
         protected Gee.Collection<AppCenterCore.Package> get_packages () {
             var tree_set = new Gee.TreeSet<AppCenterCore.Package> ();
             foreach (var r in list_box.get_children ()) {
                 var row = (Widgets.AppListRow)r;
-                if (row.has_package ()) {
+                if (row.get_package () != null) {
                     tree_set.add (row.get_package ());
                 }
-            };
+            }
 
             return tree_set;
         }
 
         [CCode (instance_pos = -1)]
         protected virtual int package_row_compare (Widgets.AppListRow row1, Widgets.AppListRow row2) {
+            if (row1.get_name_label () == null || row2.get_name_label () == null) {
+                return 0;
+            }
+
             return row1.get_name_label ().collate (row2.get_name_label ());
         }
 
@@ -109,9 +115,9 @@
                 packages_changing--;
             }
 
-            assert (packages_changing >=0);
+            assert (packages_changing >= 0);
             if (packages_changing == 0) {
-                after_add_remove_change_row ();
+                list_changed ();
             }
         }
     }

=== modified file 'src/Application.vala'
--- src/Application.vala	2016-08-23 14:35:57 +0000
+++ src/Application.vala	2016-10-13 21:30:22 +0000
@@ -25,10 +25,13 @@
 
     public static bool show_updates;
     public static bool silent;
-    MainWindow main_window;
+
+    public MainWindow? main_window { public get; private set; default = null; }
+
     construct {
         application_id = "org.pantheon.appcenter";
         flags = ApplicationFlags.FLAGS_NONE;
+        
         Intl.setlocale (LocaleCategory.ALL, "");
         Intl.textdomain (Build.GETTEXT_PACKAGE);
 
@@ -55,6 +58,11 @@
         add_main_option_entries (appcenter_options);
     }
 
+    public static int main (string[] args) {
+        var application = new App ();
+        return application.run (args);
+    }
+
     public override void activate () {
         var client = AppCenterCore.Client.get_default ();
         if (silent) {
@@ -72,27 +80,20 @@
         }
 
         if (main_window == null) {
-            client.update_cache.begin (true);
-
             main_window = new MainWindow (this);
             main_window.destroy.connect (() => {
                 main_window = null;
             });
 
             add_window (main_window);
-            main_window.show_all ();
             if (show_updates) {
                 main_window.go_to_installed ();
             }
+
+            main_window.show_all ();
         } else {
             client.interface_cancellable.reset ();
+            main_window.present ();
         }
-
-        main_window.present ();
     }
-}
-
-public static int main (string[] args) {
-    var application = new AppCenter.App ();
-    return application.run (args);
-}
+}
\ No newline at end of file

=== modified file 'src/Core/ChangeInformation.vala'
--- src/Core/ChangeInformation.vala	2016-10-07 17:44:50 +0000
+++ src/Core/ChangeInformation.vala	2016-10-13 21:30:22 +0000
@@ -169,7 +169,7 @@
         progress_denom = 200.0f;
     }
 
-    public void ProgressCallback (Pk.Progress progress, Pk.ProgressType type) {
+    public void progress_callback (Pk.Progress progress, Pk.ProgressType type) {
         switch (type) {
             case Pk.ProgressType.ALLOW_CANCEL:
                 can_cancel = progress.allow_cancel;
@@ -181,14 +181,14 @@
                     if (current_status != Pk.Status.DOWNLOAD) {
                         progress_denom = 100.0f;
                     }
-                }
-                /* transaction changed so progress count is starting over */
-                else if ((Pk.Status) progress.status != current_status) {
+                } else if ((Pk.Status) progress.status != current_status) {
+                    /* transaction changed so progress count is starting over */
                     current_status = (Pk.Status) progress.status;
                     current_progress = last_progress;
                 }
 
                 last_progress = progress.percentage;
+                
                 double progress_sum = current_progress + last_progress;
                 this.progress = progress_sum / progress_denom;
                 progress_changed ();

=== modified file 'src/Core/Client.vala'
--- src/Core/Client.vala	2016-10-09 15:09:46 +0000
+++ src/Core/Client.vala	2016-10-13 21:30:22 +0000
@@ -22,37 +22,38 @@
     public bool updating_cache { public get; private set; }
 
     public AppCenterCore.Package os_updates { public get; private set; }
+    public GLib.Cancellable interface_cancellable;
 
-    private Gee.LinkedList<AppCenter.Task> task_list;
-    private Gee.LinkedList<AppCenter.Task> task_with_agreement_list;
+    private Gee.LinkedList<AppCenterCore.Task> task_list;
+    private Gee.LinkedList<AppCenterCore.Task> task_with_agreement_list;
     private Gee.HashMap<string, AppCenterCore.Package> package_list;
     private AppStream.Database appstream_database;
-    public GLib.Cancellable interface_cancellable;
     private GLib.DateTime last_cache_update;
     private uint updates_number = 0U;
 
+    private SuspendControl sc;
+
     private Client () {
-        try {
-            appstream_database.get_all_components ().foreach ((comp) => {
-                var package = new AppCenterCore.Package (comp);
-                foreach (var pkg_name in comp.get_pkgnames ()) {
-                    package_list.set (pkg_name, package);
-                }
-            });
-        } catch (Error e) {
-            error (e.message);
-        }
+
     }
 
     construct {
-        task_list = new Gee.LinkedList<AppCenter.Task> ();
-        task_with_agreement_list = new Gee.LinkedList<AppCenter.Task> ();
+        task_list = new Gee.LinkedList<AppCenterCore.Task> ();
+        task_with_agreement_list = new Gee.LinkedList<AppCenterCore.Task> ();
         package_list = new Gee.HashMap<string, AppCenterCore.Package> (null, null);
         interface_cancellable = new GLib.Cancellable ();
+        sc = new SuspendControl ();
 
         appstream_database = new AppStream.Database ();
+
         try {
             appstream_database.open ();
+            appstream_database.get_all_components ().foreach ((comp) => {
+                var package = new AppCenterCore.Package (comp);
+                foreach (var pkg_name in comp.get_pkgnames ()) {
+                    package_list.set (pkg_name, package);
+                }
+            });
         } catch (Error e) {
             error (e.message);
         }
@@ -61,6 +62,7 @@
         os_updates_component.id = AppCenterCore.Package.OS_UPDATES_ID;
         os_updates_component.name = _("Operating System Updates");
         os_updates_component.summary = _("Updates to system components");
+
         var icon = new AppStream.Icon ();
         icon.set_name ("distributor-logo");
         icon.set_kind (AppStream.IconKind.STOCK);
@@ -72,28 +74,33 @@
         return !task_list.is_empty;
     }
 
-    private AppCenter.Task request_task (bool requires_user_agreement = true) {
-        AppCenter.Task task = new AppCenter.Task ();
-        task_list.add (task);
+    private AppCenterCore.Task request_task (bool requires_user_agreement = true) {
+        AppCenterCore.Task task = new AppCenterCore.Task ();
         if (requires_user_agreement) {
             if (task_with_agreement_list.size == 0) {
                 Pk.polkit_agent_open ();
             }
+
             task_with_agreement_list.add (task);
+        } else {
+            task_list.add (task);
         }
+
         return task;
     }
 
-    private void release_task (AppCenter.Task task) {
-        task_list.remove (task);
-        if (task_list.is_empty) {
+    private void release_task (AppCenterCore.Task task) {
+        if (task in task_with_agreement_list) {
+            task_with_agreement_list.remove (task);
+            if (task_with_agreement_list.size == 0) {
+                Pk.polkit_agent_close ();
+            }
+        } else if (task in task_list) {
+            task_list.remove (task);
+        }
+
+        if (task_list.is_empty && task_with_agreement_list.is_empty) {
             tasks_finished ();
-            if (task in task_with_agreement_list) {
-                task_with_agreement_list.remove (task);
-                if (task_with_agreement_list.size == 0) {
-                    Pk.polkit_agent_close ();
-                }
-            }
         }
     }
 
@@ -102,15 +109,16 @@
             return appstream_database.get_component_by_id (extension); 
         } catch (Error e) {
             warning ("%s\n", e.message);
+            throw e;
         }
-        
-        return null;
     }
 
     public async Pk.Exit install_package (Package package, Pk.ProgressCallback cb, GLib.Cancellable cancellable) throws GLib.Error {
         Pk.Exit exit_status = Pk.Exit.UNKNOWN;
-        AppCenter.Task install_task = request_task ();
-        AppCenter.Task search_task = request_task ();
+
+        AppCenterCore.Task install_task = request_task ();
+        AppCenterCore.Task search_task = request_task ();
+
         string[] packages_ids = {};
         foreach (var pkg_name in package.component.get_pkgnames ()) {
             packages_ids += pkg_name;
@@ -119,7 +127,7 @@
         packages_ids += null;
 
         try {
-            var results = yield search_task.resolve_async (Pk.Bitfield.from_enums (Pk.Filter.NEWEST, Pk.Filter.ARCH), packages_ids, cancellable, () => {});
+            Pk.Results results = yield search_task.resolve_async (Pk.Bitfield.from_enums (Pk.Filter.NEWEST, Pk.Filter.ARCH), packages_ids, cancellable, () => {});
             packages_ids = {};
 
             results.get_package_array ().foreach ((package) => {
@@ -143,13 +151,15 @@
 
         release_task (search_task);
         release_task (install_task);
+
         return exit_status;
     }
 
     public async Pk.Exit update_package (Package package, Pk.ProgressCallback cb, GLib.Cancellable cancellable) throws GLib.Error {
         Pk.Exit exit_status = Pk.Exit.UNKNOWN;
-        SuspendControl sc = new SuspendControl ();
-        AppCenter.Task update_task = request_task ();
+
+        AppCenterCore.Task update_task = request_task ();
+
         string[] packages_ids = {};
         foreach (var pk_package in package.change_information.changes) {
             packages_ids += pk_package.get_id ();
@@ -159,15 +169,17 @@
 
         try {
             sc.inhibit ();
-            var results = yield update_task.update_packages_async (packages_ids, cancellable, cb);
+
+            Pk.Results results = yield update_task.update_packages_async (packages_ids, cancellable, cb);
             exit_status = results.get_exit_code ();
         } catch (Error e) {
-            throw e;
-        } finally {
             sc.uninhibit ();
-            release_task (update_task);
+            throw e;
         }
 
+        sc.uninhibit ();
+        release_task (update_task);
+
         if (exit_status != Pk.Exit.SUCCESS) {
             throw new GLib.IOError.FAILED (Pk.Exit.enum_to_string (exit_status));
         } else {
@@ -181,17 +193,21 @@
 
     public async Pk.Exit remove_package (Package package, Pk.ProgressCallback cb, GLib.Cancellable cancellable) throws GLib.Error {
         Pk.Exit exit_status = Pk.Exit.UNKNOWN;
-        AppCenter.Task remove_task = request_task ();
-        AppCenter.Task search_task = request_task ();
+
+        AppCenterCore.Task remove_task = request_task ();
+        AppCenterCore.Task search_task = request_task ();
+
         string[] packages_ids = {};
         foreach (var pkg_name in package.component.get_pkgnames ()) {
             packages_ids += pkg_name;
         }
+
         packages_ids += null;
 
         try {
-            var results = yield search_task.resolve_async (Pk.Bitfield.from_enums (Pk.Filter.INSTALLED, Pk.Filter.NEWEST), packages_ids, cancellable, () => {});
+            Pk.Results results = yield search_task.resolve_async (Pk.Bitfield.from_enums (Pk.Filter.INSTALLED, Pk.Filter.NEWEST), packages_ids, cancellable, () => {});
             packages_ids = {};
+
             results.get_package_array ().foreach ((package) => {
                 packages_ids += package.package_id;
             });
@@ -204,34 +220,40 @@
             throw e;
         }
 
+        release_task (search_task);
+        release_task (remove_task);    
         yield refresh_updates ();
-        release_task (search_task);
-        release_task (remove_task);
+
         return exit_status;
     }
 
     public async void get_updates () {
-        AppCenter.Task update_task = request_task (false);
-        AppCenter.Task details_task = request_task (false);
+        AppCenterCore.Task update_task = request_task (false);
+        AppCenterCore.Task details_task = request_task (false);
+
         try {
-            Pk.Results result = yield update_task.get_updates_async (0, interface_cancellable, (t, p) => { });
+            Pk.Results results = yield update_task.get_updates_async (0, interface_cancellable, (t, p) => {});
+
             string[] packages_array = {};
-            result.get_package_array ().foreach ((pk_package) => {
+            results.get_package_array ().foreach ((pk_package) => {
                 packages_array += pk_package.get_id ();
             });
 
             // We need a null to show to PackageKit that it's then end of the array.
             packages_array += null;
 
-            Pk.Results result2 = yield details_task.get_details_async (packages_array , interface_cancellable, (t, p) => { });
-            result2.get_details_array ().foreach ((pk_detail) => {
+            results = yield details_task.get_details_async (packages_array , interface_cancellable, (t, p) => {});
+            results.get_details_array ().foreach ((pk_detail) => {
                 var pk_package = new Pk.Package ();
+
                 try {
                     pk_package.set_id (pk_detail.get_package_id ());
+
                     unowned string pkg_name = pk_package.get_name ();
                     var package = package_list.get (pkg_name);
                     if (package == null) {
                         package = os_updates;
+
                         var pkgnames = os_updates.component.pkgnames;
                         pkgnames += pkg_name;
                         os_updates.component.pkgnames = pkgnames;
@@ -241,46 +263,51 @@
                     package.change_information.details.add (pk_detail);
                     package.update_state ();
                 } catch (Error e) {
-                    critical (e.message);
+                    warning (e.message);
                 }
             });
         } catch (Error e) {
             // Error code 19 is for operation canceled.
             if (e.code != 19) {
-                critical (e.message);
+                warning (e.message);
             }
+        } finally {
+            updates_available ();
         }
 
         release_task (details_task);
-        release_task (update_task);
-        updates_available ();
+        release_task (update_task);        
     }
 
     public async Gee.Collection<AppCenterCore.Package> get_installed_applications () {
-        var packages = new Gee.TreeSet<AppCenterCore.Package> ();
-        var packages_list = yield get_installed_packages ();
-        foreach (var pk_package in packages_list) {
+        var applications = new Gee.TreeSet<AppCenterCore.Package> ();
+        var installed_packages = yield get_installed_packages ();
+        foreach (var pk_package in installed_packages) {
             var package = package_list.get (pk_package.get_name ());
             if (package != null) {
                 package.installed_packages.add (pk_package);
                 package.update_state ();
-                packages.add (package);
+                applications.add (package);
             }
         }
 
-        return packages;
+        return applications;
     }
 
     public Gee.Collection<AppCenterCore.Package> search_applications (string? query, AppStream.Category? category) {
         var apps = new Gee.TreeSet<AppCenterCore.Package> ();
-        string categories = category == null ? null : get_string_from_categories (category);
+        string? categories = category == null ? null : get_string_from_categories (category);
         try {
             var comps = appstream_database.find_components (query, categories);
             comps.foreach ((comp) => {
+                if (comp.get_pkgnames ().length == 0) {
+                    return;
+                }
+
                 apps.add (package_list.get (comp.get_pkgnames ()[0]));
             });
         } catch (Error e) {
-            critical (e.message);
+            warning (e.message);
         }
 
         return apps;
@@ -307,12 +334,15 @@
     }
 
     public Pk.Package? get_app_package (string application, Pk.Bitfield additional_filters = 0) throws GLib.Error {
-        AppCenter.Task packages_task = request_task (false);
         Pk.Package? package = null;
+
+        AppCenterCore.Task packages_task = request_task (false);
+
         var filter = Pk.Bitfield.from_enums (Pk.Filter.NEWEST);
         filter |= additional_filters;
+
         try {
-            var results = packages_task.search_names_sync (filter, { application, null }, interface_cancellable, () => {});
+            Pk.Results results = packages_task.search_names_sync (filter, { application, null }, interface_cancellable, () => {});
             var array = results.get_package_array ();
             if (array.length > 0) {
                 package = array.get (0);
@@ -327,23 +357,26 @@
     }
 
     public async void refresh_updates () {
-        var update_task = new AppCenter.Task ();
+        AppCenterCore.Task update_task = request_task (false);
         updating_cache = true;
 
         try {
-            Pk.Results result = yield update_task.get_updates_async (0, null, (t, p) => {});
+            Pk.Results results = yield update_task.get_updates_async (0, null, (t, p) => {});
             bool was_empty = updates_number == 0U;
-            updates_number = get_package_count (result.get_package_array ());
+            updates_number = get_package_count (results.get_package_array ());
+
+            var application = (AppCenter.App)GLib.Application.get_default ();
             if (was_empty && updates_number != 0U) {
                 string title = ngettext ("Update Available", "Updates Available", updates_number);
                 string body = ngettext ("%u update is available for your system", "%u updates are available for your system", updates_number).printf (updates_number);
+
                 var notification = new Notification (title);
                 notification.set_body (body);
                 notification.set_icon (new ThemedIcon ("system-software-install"));
                 notification.set_default_action ("app.open-application");
-                Application.get_default ().send_notification ("updates", notification);
+                application.send_notification ("updates", notification);
             } else {
-                Application.get_default ().withdraw_notification ("updates");
+                application.withdraw_notification ("updates");
             }
 
 #if HAVE_UNITY
@@ -354,12 +387,14 @@
         } catch (Error e) {
             critical (e.message);
         }
+
         updating_cache = false;
     }
 
     public uint get_package_count (GLib.GenericArray<weak Pk.Package> package_array) {
         bool os_update_found = false;
         var result_comp = new Gee.TreeSet<AppStream.Component> ();
+
         package_array.foreach ((pk_package) => {
             var comp = package_list.get (pk_package.get_name ());
             if (comp != null) {
@@ -380,7 +415,7 @@
     public async void update_cache (bool force = false) {
         // One cache update a day, keeps the doctor away!
         if (force || last_cache_update == null || (new DateTime.now_local ()).difference (last_cache_update) >= GLib.TimeSpan.DAY) {
-            var refresh_task = new AppCenter.Task ();
+            AppCenterCore.Task refresh_task = request_task (false);
             try {
                 yield refresh_task.refresh_cache_async (false, null, (t, p) => { });
                 last_cache_update = new DateTime.now_local ();
@@ -389,30 +424,32 @@
             }
 
             refresh_updates.begin ();
+            release_task (refresh_task);
         }
 
-        GLib.Timeout.add_seconds (60*60*24, () => {
+        GLib.Timeout.add_seconds (60 * 60 * 24, () => {
             update_cache.begin ();
             return GLib.Source.REMOVE;
         });
     }
 
     public async Gee.TreeSet<Pk.Package> get_installed_packages () {
-        var packages_task = request_task ();
+        AppCenterCore.Task packages_task = request_task ();
+
         var filter = Pk.Bitfield.from_enums (Pk.Filter.INSTALLED, Pk.Filter.NEWEST);
         var installed = new Gee.TreeSet<Pk.Package> ();
+
         try {
-            Pk.Results result = yield packages_task.get_packages_async (filter, null, (prog, type) => {});
-            result.get_package_array ().foreach ((pk_package) => {
+            Pk.Results results = yield packages_task.get_packages_async (filter, null, (t, p) => {});
+            results.get_package_array ().foreach ((pk_package) => {
                 installed.add (pk_package);
             });
-
-            release_task (packages_task);
         } catch (Error e) {
-            critical (e.message);
-            release_task (packages_task);
+            warning (e.message);
         }
 
+        release_task (packages_task);
+
         return installed;
     }
 

=== modified file 'src/Core/Package.vala'
--- src/Core/Package.vala	2016-09-14 16:58:13 +0000
+++ src/Core/Package.vala	2016-10-13 21:30:22 +0000
@@ -33,7 +33,7 @@
 
     public const string OS_UPDATES_ID = "xxx-os-updates";
 
-    public AppStream.Component component { public get; private set; }
+    public AppStream.Component component { get; construct; }
     public ChangeInformation change_information { public get; private set; }
     public Gee.TreeSet<Pk.Package> installed_packages { public get; private set; }
     public GLib.Cancellable action_cancellable { public get; private set; }
@@ -72,20 +72,25 @@
     public bool is_os_updates {
         get {
             return component.id == "xxx-os-updates";
-         }
-     }
-
-    public Package (AppStream.Component component) {
-        this.component = component;
+        }
+    }
+
+    private string? name = null;
+    private string? summary = null;
+    private string? version = null;
+
+    construct {
         installed_packages = new Gee.TreeSet<Pk.Package> ();
         change_information = new ChangeInformation ();
-        change_information.status_changed.connect (() => {
-            info_changed (change_information.status);
-        });
+        change_information.status_changed.connect (() => info_changed (change_information.status));
 
         action_cancellable = new GLib.Cancellable ();
     }
 
+    public Package (AppStream.Component component) {
+        Object (component: component);
+    }
+
     public void update_state () {
         if (installed) {
             if (change_information.has_changes ()) {
@@ -102,6 +107,7 @@
         if (state != State.UPDATE_AVAILABLE) {
             return false;
         }
+
         return yield perform_operation (State.UPDATING, State.INSTALLED, State.UPDATE_AVAILABLE);
     }
 
@@ -109,11 +115,12 @@
         if (state != State.NOT_INSTALLED) {
             return false;
         }
+
         if (yield perform_operation (State.INSTALLING, State.INSTALLED, State.NOT_INSTALLED)) {
             /* TODO: Move this to a higher level */
-            var application = (Gtk.Application)Application.get_default ();
-            var window = application.get_active_window ().get_window ();
-            if ((window.get_state () & Gdk.WindowState.FOCUSED) == 0) {
+            var application = (AppCenter.App)GLib.Application.get_default ();
+            var window = application.main_window;
+            if (window == null || !(Gdk.WindowState.FOCUSED in window.get_window ().get_state ())) {
                 var notification = new Notification (_("Application installed"));
                 notification.set_body (_("%s has been successfully installed").printf (get_name ()));
                 notification.set_icon (new ThemedIcon ("system-software-install"));
@@ -121,6 +128,7 @@
 
                 application.send_notification ("installed", notification);
             }
+
             return true;
         }
 
@@ -131,6 +139,7 @@
         if (state != State.INSTALLED) {
             return false;
         }
+
         return yield perform_operation (State.REMOVING, State.NOT_INSTALLED, State.INSTALLED);
     }
 
@@ -144,6 +153,7 @@
         } finally {
             clean_up_package_operation (exit_status, after_success, after_fail);
         }
+
         return (exit_status == Pk.Exit.SUCCESS);
     }
 
@@ -156,7 +166,7 @@
     }
 
     private async Pk.Exit perform_package_operation () throws GLib.Error {
-        Pk.ProgressCallback cb = change_information.ProgressCallback;
+        Pk.ProgressCallback cb = change_information.progress_callback;
         var client = AppCenterCore.Client.get_default ();
         switch (state) {
             case State.UPDATING:
@@ -184,31 +194,39 @@
      }
 
     public string? get_name () {
+        if (name != null) {
+            return name;
+        }
+
         var _name = component.get_name ();
         if (_name != null) {
-            return _name;
-        }
-
-        var package = find_package ();
-        if (package != null) {
-            return package.get_name ();
-        }
-
-        return null;
+            name = _name;
+        } else {
+            var package = find_package ();
+            if (package != null) {
+                name = package.get_name ();
+            }
+        }
+
+        return name;
     }
 
     public string? get_summary () {
-        var summary = component.get_summary ();
         if (summary != null) {
             return summary;
         }
 
-        var package = find_package ();
-        if (package != null) {
-            return package.get_summary ();
+        var _summary = component.get_summary ();
+        if (_summary != null) {
+            summary = _summary;
+        } else {
+            var package = find_package ();
+            if (package != null) {
+                summary = package.get_summary ();
+            }
         }
 
-        return null;
+        return summary;
     }
 
     public string get_progress_description () {
@@ -265,6 +283,10 @@
     }
 
     public string? get_version () {
+        if (version != null) {
+            return version;
+        }
+
         var package = find_package ();
         if (package != null) {
             string returned = package.get_version ();
@@ -275,10 +297,10 @@
                 returned = returned.split (":", 2)[1];
             }
 
-            return returned;
+            version = returned;
         }
 
-        return null;
+        return version;
     }
 
     private Pk.Package? find_package (bool installed = false) {
@@ -294,7 +316,7 @@
 
             return AppCenterCore.Client.get_default ().get_app_package (component.get_pkgnames ()[0], filter);
         } catch (Error e) {
-            critical (e.message);
+            warning (e.message);
             return null;
         }
     }

=== modified file 'src/Core/Task.vala'
--- src/Core/Task.vala	2016-07-18 21:16:57 +0000
+++ src/Core/Task.vala	2016-10-13 21:30:22 +0000
@@ -18,11 +18,7 @@
  * Authored by: Corentin Noël <[e-mail]>
  */
 
-public class AppCenter.Task : Pk.Task {
-    public Task () {
-        
-    }
-
+public class AppCenterCore.Task : Pk.Task {
     public override void untrusted_question (uint request, Pk.Results results) {
         user_accepted (request);
     }

=== modified file 'src/MainWindow.vala'
--- src/MainWindow.vala	2016-10-07 19:18:16 +0000
+++ src/MainWindow.vala	2016-10-13 21:30:22 +0000
@@ -14,7 +14,20 @@
 * with this program. If not, see http://www.gnu.org/licenses/.
 */
 
+
+// Helper method for easier code reading
+public static void set_widget_visible (Gtk.Widget widget, bool visible) {
+    widget.no_show_all = !visible;
+    if (visible) {
+        widget.show_all ();
+    } else {
+        widget.hide ();
+    }
+}
+
 public class AppCenter.MainWindow : Gtk.ApplicationWindow {
+    public static Views.InstalledView installed_view { get; private set; }
+
     private Gtk.Revealer view_mode_revealer;
     private Gtk.Stack custom_title_stack;
     private Gtk.Label category_header;
@@ -29,16 +42,25 @@
     private Gtk.Stack button_stack;
     private ulong task_finished_connection = 0U;
     private Gee.Deque<string> return_button_history;
-    
-    public static Views.InstalledView installed_view { get; private set; }
 
     public MainWindow (Gtk.Application app) {
         Object (application: app);
+        app.set_accels_for_action ("win.go-back", {"<Alt>Left"});
+    }
+
+    construct {
+        icon_name = "system-software-install";
+        title = _("AppCenter");
+        window_position = Gtk.WindowPosition.CENTER;
+
+        var go_back = new SimpleAction ("go-back", null);
+        go_back.activate.connect (view_return);
+        add_action (go_back);
 
         weak Gtk.IconTheme default_theme = Gtk.IconTheme.get_default ();
         default_theme.add_resource_path ("/org/pantheon/appcenter/icons");
 
-        unowned Settings saved_state = Settings.get_default ();
+        unowned AppCenter.Settings saved_state = AppCenter.Settings.get_default ();
         set_default_size (saved_state.window_width, saved_state.window_height);
 
         // Maximize window if necessary
@@ -50,60 +72,17 @@
                 break;
         }
 
-        view_mode.selected = 0;
-        search_entry.grab_focus_without_selecting ();
-
-        var go_back = new SimpleAction ("go-back", null);
-        go_back.activate.connect (view_return);
-        add_action (go_back);
-        app.set_accels_for_action ("win.go-back", {"<Alt>Left"});
-
-        search_entry.search_changed.connect (() => trigger_search ());
-
-        view_mode.notify["selected"].connect (() => {
-            switch (view_mode.selected) {
-                case 0:
-                    stack.set_visible_child (category_view);
-                    break;
-                default:
-                    stack.set_visible_child (installed_view);
-                    break;
-            }
-        });
-
-        search_entry.key_press_event.connect ((event) => {
-            if (event.keyval == Gdk.Key.Escape) {
-                search_entry.text = "";
-                return true;
-            }
-            
-            return false;
-        });
-
-        return_button.clicked.connect (view_return);
-        search_all_button.clicked.connect (search_all_apps);
-
-        installed_view.get_apps.begin ();
-
-        category_view.subview_entered.connect (view_opened);
-        installed_view.subview_entered.connect (view_opened);
-        search_view.subview_entered.connect (view_opened);
-    }
-
-    construct {
-        icon_name = "system-software-install";
-        title = _("AppCenter");
-        window_position = Gtk.WindowPosition.CENTER;
-
         return_button = new Gtk.Button ();
         return_button.no_show_all = true;
         return_button.get_style_context ().add_class ("back-button");
         return_button_history = new Gee.LinkedList<string> ();
-        
+        return_button.clicked.connect (view_return);
+
         search_all_button = new Gtk.Button.with_label (_("Search Apps"));
         search_all_button.no_show_all = true;
         search_all_button.get_style_context ().add_class ("back-button");
-        
+        search_all_button.clicked.connect (search_all_apps);
+
         button_stack = new Gtk.Stack ();
         button_stack.add (return_button);
         button_stack.add (search_all_button);
@@ -112,6 +91,17 @@
         view_mode = new Granite.Widgets.ModeButton ();
         view_mode.append_text (_("Categories"));
         view_mode.append_text (C_("view", "Updates"));
+        view_mode.selected = 0;
+        view_mode.notify["selected"].connect (() => {
+            switch (view_mode.selected) {
+                case 0:
+                    stack.set_visible_child (category_view);
+                    break;
+                default:
+                    stack.set_visible_child (installed_view);
+                    break;
+            }
+        });
 
         view_mode_revealer = new Gtk.Revealer ();
         view_mode_revealer.reveal_child = true;
@@ -128,6 +118,15 @@
 
         search_entry = new Gtk.SearchEntry ();
         search_entry.placeholder_text = _("Search Apps");
+        search_entry.search_changed.connect (() => trigger_search ());
+        search_entry.key_press_event.connect ((event) => {
+            if (event.keyval == Gdk.Key.Escape) {
+                search_entry.text = "";
+                return true;
+            }
+            
+            return false;
+        });
 
         /* HeaderBar */
         headerbar = new Gtk.HeaderBar ();
@@ -139,8 +138,13 @@
         set_titlebar (headerbar);
 
         category_view = new Views.CategoryView ();
+        category_view.subview_entered.connect (view_opened);
+
         installed_view = new Views.InstalledView ();
+        installed_view.subview_entered.connect (view_opened);
+
         search_view = new Views.SearchView ();
+        search_view.subview_entered.connect (view_opened);
 
         stack = new Gtk.Stack ();
         stack.transition_type = Gtk.StackTransitionType.SLIDE_LEFT_RIGHT;
@@ -148,6 +152,17 @@
         stack.add (installed_view);
         stack.add (search_view);
 
+        var provider = new Gtk.CssProvider ();
+        try {
+            provider.load_from_data (CATEGORIES_STYLE_CSS, CATEGORIES_STYLE_CSS.length);
+            Gtk.StyleContext.add_provider_for_screen (get_screen (), provider, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
+        } catch (Error e) {
+            critical (e.message);
+        }
+
+        search_entry.grab_focus_without_selecting ();
+        installed_view.get_apps.begin ();
+
         add (stack);
     }
 
@@ -155,9 +170,11 @@
         int window_width;
         int window_height;
         get_size (out window_width, out window_height);
-        unowned Settings saved_state = Settings.get_default ();
+
+        unowned AppCenter.Settings saved_state = AppCenter.Settings.get_default ();
         saved_state.window_width = window_width;
         saved_state.window_height = window_height;
+
         if (is_maximized) {
             saved_state.window_state = Settings.WindowState.MAXIMIZED;
         } else {
@@ -237,6 +254,7 @@
         if (return_button_history.is_empty || return_button_history.peek_head () != return_name) {
             return_button_history.offer_head (return_name);
         }
+
         return_button.label = return_name;
         return_button.no_show_all = false;
         return_button.show_all ();
@@ -249,6 +267,7 @@
 
         search_entry.sensitive = allow_search;
         search_entry.grab_focus_without_selecting ();
+
         if (stack.visible_child == category_view && category_view.currently_viewed_category != null) {
             search_entry.placeholder_text = _("Search %s").printf (category_view.currently_viewed_category.get_name ());
         }
@@ -270,6 +289,7 @@
         if (stack.visible_child == category_view) {
             search_entry.placeholder_text = _("Search Apps");
         }
+
         search_entry.sensitive = true;
         search_entry.grab_focus_without_selecting ();
 

=== modified file 'src/Settings.vala'
--- src/Settings.vala	2015-11-05 16:52:40 +0000
+++ src/Settings.vala	2016-10-13 21:30:22 +0000
@@ -40,10 +40,12 @@
     public WindowState window_state { get; set; }
     public bool developer_mode { get; set; }
 
-    private static Settings main_settings;
-    public static unowned Settings get_default () {
-        if (main_settings == null)
+    private static Settings? main_settings;
+    public static unowned Settings? get_default () {
+        if (main_settings == null) {
             main_settings = new Settings ();
+        }
+
         return main_settings;
     }
 

=== modified file 'src/Views/AppInfoView.vala'
--- src/Views/AppInfoView.vala	2016-09-08 09:52:03 +0000
+++ src/Views/AppInfoView.vala	2016-10-13 21:30:22 +0000
@@ -20,14 +20,14 @@
 
 namespace AppCenter.Views {
     public class AppInfoView : AppCenter.AbstractAppContainer {
-        Gtk.Image app_screenshot;
-        Gtk.Stack screenshot_stack;
-        Gtk.Label app_screenshot_not_found;
-        Gtk.Label app_version;
-        Gtk.TextView app_description;
-        Gtk.ListBox extension_box;
-        Gtk.Label extension_label;
-        Gtk.Grid content_grid;
+        private Gtk.Image app_screenshot;
+        private Gtk.Stack screenshot_stack;
+        private Gtk.Label app_screenshot_not_found;
+        private Gtk.Label app_version;
+        private Gtk.TextView app_description;
+        private Gtk.ListBox extension_box;
+        private Gtk.Label extension_label;
+        private Gtk.Grid content_grid;
 
         construct {
             image.margin_top = 12;
@@ -46,9 +46,11 @@
             app_screenshot_spinner.active = true;
 
             app_screenshot_not_found = new Gtk.Label (_("Screenshot Not Available"));
-            app_screenshot_not_found.get_style_context ().add_class (Gtk.STYLE_CLASS_BACKGROUND);
-            app_screenshot_not_found.get_style_context ().add_class (Gtk.STYLE_CLASS_DIM_LABEL);
-            app_screenshot_not_found.get_style_context ().add_class ("h2");
+
+            var style_context = app_screenshot_not_found.get_style_context ();
+            style_context.add_class (Gtk.STYLE_CLASS_BACKGROUND);
+            style_context.add_class (Gtk.STYLE_CLASS_DIM_LABEL);
+            style_context.add_class ("h2");
 
             screenshot_stack = new Gtk.Stack ();
             screenshot_stack.margin_bottom = 24;
@@ -57,7 +59,6 @@
             screenshot_stack.add (app_screenshot);
             screenshot_stack.add (app_screenshot_not_found);
 
-            package_name = new Gtk.Label (null);
             package_name.margin_top = 12;
             package_name.xalign = 0;
             package_name.get_style_context ().add_class ("h1");
@@ -68,14 +69,18 @@
             app_version.xalign = 0;
             app_version.hexpand = true;
             app_version.valign = Gtk.Align.CENTER;
-            app_version.get_style_context ().add_class (Gtk.STYLE_CLASS_DIM_LABEL);
-            app_version.get_style_context ().add_class ("h3");
-
-            package_summary = new Gtk.Label (null);
+
+            style_context = app_version.get_style_context ();
+            style_context.add_class (Gtk.STYLE_CLASS_DIM_LABEL);
+            style_context.add_class ("h3");
+
             package_summary.xalign = 0;
             package_summary.valign = Gtk.Align.START;
-            package_summary.get_style_context ().add_class (Gtk.STYLE_CLASS_DIM_LABEL);
-            package_summary.get_style_context ().add_class ("h2");
+
+            style_context = package_summary.get_style_context ();
+            style_context.add_class (Gtk.STYLE_CLASS_DIM_LABEL);
+            style_context.add_class ("h2");
+
             package_summary.wrap = true;
             package_summary.set_lines (3);
             package_summary.wrap_mode = Pango.WrapMode.WORD_CHAR;
@@ -96,6 +101,23 @@
             content_grid.add (screenshot_stack);
             content_grid.add (app_description);
 
+            parse_description (package.component.get_description ());
+
+            if (package.component.get_extensions ().length > 0) {
+                extension_box = new Gtk.ListBox ();
+                extension_box.selection_mode = Gtk.SelectionMode.NONE;
+
+                extension_label = new Gtk.Label ("<b>" + _("Extensions:") + "</b>");
+                extension_label.margin_top = 12;
+                extension_label.use_markup = true;
+                extension_label.get_style_context ().add_class ("h3");
+                extension_label.halign = Gtk.Align.START;
+
+                content_grid.add (extension_label);
+                content_grid.add (extension_box);
+                load_extensions.begin ();
+            }
+
             var scrolled = new Gtk.ScrolledWindow (null, null);
             scrolled.hscrollbar_policy = Gtk.PolicyType.NEVER;
             scrolled.expand = true;
@@ -116,28 +138,7 @@
         }
 
         public AppInfoView (AppCenterCore.Package package) {
-            this.package = package;
-            set_up_package (128);
-
-            parse_description (package.component.get_description ());
-
-            if (package.component.get_extensions ().length > 0) {
-                extension_box = new Gtk.ListBox ();
-                extension_box.selection_mode = Gtk.SelectionMode.NONE;
-
-                extension_label = new Gtk.Label ("<b>" + _("Extensions:") + "</b>");
-                extension_label.margin_top = 12;
-                extension_label.use_markup = true;
-                extension_label.get_style_context ().add_class ("h3");
-                extension_label.halign = Gtk.Align.START;
-
-                content_grid.add (extension_label);
-                content_grid.add (extension_box);
-                load_extensions.begin ();
-            }
-
-            action_button.set_suggested_action_header ();
-            uninstall_button.set_destructive_action_header ();
+            Object (package: package, icon_size: 128);
         }
 
         private async void load_extensions () {
@@ -187,12 +188,15 @@
 
         // We need to first download the screenshot locally so that it doesn't freeze the interface.
         private void set_screenshot (string url) {
-            var ret = GLib.DirUtils.create_with_parents (GLib.Environment.get_tmp_dir () + Path.DIR_SEPARATOR_S + ".appcenter", 0755);
+            string tmp_dir = GLib.Environment.get_tmp_dir ();
+            string tmp_path = Path.build_filename (tmp_dir, ".appcenter");
+
+            var ret = GLib.DirUtils.create_with_parents (tmp_path, 0755);
             if (ret == -1) {
-                critical ("Error creating the temporary folder: GFileError #%d", GLib.FileUtils.error_from_errno (GLib.errno));
+                warning ("Error creating the temporary folder: GFileError #%d", GLib.FileUtils.error_from_errno (GLib.errno));
             }
 
-            string path = Path.build_path (Path.DIR_SEPARATOR_S, GLib.Environment.get_tmp_dir (), ".appcenter", "XXXXXX");
+            string path = Path.build_filename (tmp_dir, ".appcenter", "XXXXXX");
             File fileimage;
             var fd = GLib.FileUtils.mkstemp (path);
             if (fd != -1) {
@@ -201,7 +205,7 @@
                 try {
                     source.copy (fileimage, GLib.FileCopyFlags.OVERWRITE);
                 } catch (Error e) {
-                    debug (e.message);
+                    warning (e.message);
                     // The file is likely to not being found.
                     screenshot_stack.visible_child = app_screenshot_not_found;
                     return;
@@ -209,9 +213,9 @@
 
                 GLib.FileUtils.close (fd);
             } else {
-                critical ("Error create the temporary file: GFileError #%d", GLib.FileUtils.error_from_errno (GLib.errno));
+                warning ("Error create the temporary file: GFileError #%d", GLib.FileUtils.error_from_errno (GLib.errno));
                 fileimage = File.new_for_uri (url);
-                if (fileimage.query_exists () == false) {
+                if (!fileimage.query_exists ()) {
                     screenshot_stack.visible_child = app_screenshot_not_found;
                     return;
                 }

=== modified file 'src/Views/AppListView.vala'
--- src/Views/AppListView.vala	2016-09-17 19:28:03 +0000
+++ src/Views/AppListView.vala	2016-10-13 21:30:22 +0000
@@ -22,11 +22,8 @@
 namespace AppCenter.Views {
     /** AppList for Category and Search Views.  Sorts by name and does not show Uninstall Button **/
     public class AppListView : AbstractAppList {
-
-        public AppListView () {}
-
-        protected override Widgets.AppListRow make_row (AppCenterCore.Package package)  {
-            return (Widgets.AppListRow)(new Widgets.PackageRow (package, action_button_group, false));
+        protected override Widgets.AppListRow create_row (AppCenterCore.Package package)  {
+            return new Widgets.PackageRow (package, action_button_group, false);
         }
     }
 
@@ -41,6 +38,7 @@
         private bool apps_remaining_started = false;
         private GLib.Mutex update_mutex;
         private uint apps_done = 0;
+        private uint grid_timeout_id = 0;
         private Gee.LinkedList<AppCenterCore.Package> apps_to_update;
         private AppCenterCore.Package first_package;
         private SuspendControl sc;
@@ -50,6 +48,7 @@
             get {
                 return _updating_cache;
             }
+
             set {
                 if (_updating_cache != value) {
                     _updating_cache = value;
@@ -60,9 +59,9 @@
 
         construct {
             updates_on_top = true;
+            _updating_cache = true;
 
-            update_all_button = new Widgets.AppActionButton (_("Update All"));
-            update_all_button.set_suggested_action_header ();
+            update_all_button = new Widgets.AppActionButton (_("Update All"), Gtk.STYLE_CLASS_SUGGESTED_ACTION);
             update_all_button.clicked.connect (on_update_all);
             update_all_button.no_show_all = true;
             action_button_group.add_widget (update_all_button);
@@ -81,14 +80,12 @@
             sc = new SuspendControl ();
         }
 
-        public AppListUpdateView () {
-            _updating_cache = true;
+        protected override void list_changed () {
+            update_headers ();
         }
 
-        protected override void after_add_remove_change_row () {update_headers ();}
-
-        protected override Widgets.AppListRow make_row (AppCenterCore.Package package) {
-            return (Widgets.AppListRow)(new Widgets.PackageRow (package, action_button_group, false));
+        protected override Widgets.AppListRow create_row (AppCenterCore.Package package) {
+            return new Widgets.PackageRow (package, action_button_group, false);
         }
 
         protected override void on_package_changing (AppCenterCore.Package package, bool is_changing) {
@@ -146,7 +143,7 @@
                 if (row is Widgets.PackageRow) {
                     ((Widgets.PackageRow) row).set_action_sensitive (false);
                 }
-            };
+            }
             
             // Update all updateable apps
             if (apps_to_update.size > 0) {
@@ -155,9 +152,7 @@
 
                 first_package = apps_to_update[0];
                 first_package.info_changed.connect_after (after_first_package_info_changed);
-                first_package.update.begin (() => {
-                    on_app_update_end ();
-                });
+                first_package.update.begin (() => on_app_update_end ());
             } else {
                 updating_all_apps = false; 
             }
@@ -177,11 +172,10 @@
             if (status != Pk.Status.CANCEL) { /* must  be running */
                 apps_remaining_started = true;
                 for (int i = 1; i < apps_to_update.size; i++) {
-                    apps_to_update[i].update.begin (() => {
-                        on_app_update_end ();
-                    });
+                    apps_to_update[i].update.begin (() => on_app_update_end ());
                 }
-            } else { /* it was aborted - do not start updating the rest */
+            } else {
+                /* it was aborted - do not start updating the rest */
                 finish_updating_all_apps ();
             }
         }
@@ -195,6 +189,7 @@
                     finish_updating_all_apps ();
                 }
             }
+
             update_mutex.unlock ();
         }
 
@@ -209,20 +204,21 @@
             Idle.add_full (GLib.Priority.LOW, () => {
                 foreach (var row in list_box.get_children ()) {
                     if (row is Widgets.PackageRow) {
-                        var pkg_row = ((Widgets.PackageRow)(row));
-                        var pkg = pkg_row.get_package ();
+                        var package_row = (Widgets.PackageRow) row;
+                        var package = package_row.get_package ();
 
                         /* clear update information if the package was successfully updated */
                         /* This information is refreshed by Client on start up (log in) or at daily intervals */
                         /* TODO: Implement refresh on demand (or on list display?) */
-                        if (pkg.state == AppCenterCore.Package.State.INSTALLED) {
-                            pkg.change_information.clear_update_info ();
+                        if (package.state == AppCenterCore.Package.State.INSTALLED) {
+                            package.change_information.clear_update_info ();
                         }
 
-                        pkg_row.set_action_sensitive (true);
-                        pkg_row.changed ();
+                        package_row.set_action_sensitive (true);
+                        package_row.changed ();
                     }
                 }
+
                 return GLib.Source.REMOVE;
             });
         }
@@ -232,7 +228,6 @@
             schedule_header_update ();
         }
 
-        uint grid_timeout_id = 0;
         private void schedule_header_update () {
             if (grid_timeout_id > 0) {
                 return;

=== modified file 'src/Views/CategoryView.vala'
--- src/Views/CategoryView.vala	2016-09-24 21:35:11 +0000
+++ src/Views/CategoryView.vala	2016-10-13 21:30:22 +0000
@@ -21,16 +21,12 @@
 using AppCenterCore;
 
 public class AppCenter.Views.CategoryView : View {
+    public AppStream.Category? currently_viewed_category;
+
     private Gtk.FlowBox category_flow;
     private Gtk.ScrolledWindow category_scrolled;
     private string current_category;
 
-    public AppStream.Category currently_viewed_category;
-
-    public CategoryView () {
-        
-    }
-
     construct {
         category_flow = new Gtk.FlowBox ();
         category_flow.margin = 12;
@@ -50,8 +46,8 @@
         });
 
         category_flow.set_sort_func ((child1, child2) => {
-            var item1 = child1 as Widgets.CategoryItem;
-            var item2 = child2 as Widgets.CategoryItem;
+            var item1 = (Widgets.CategoryItem) child1;
+            var item2 = (Widgets.CategoryItem) child2;
             if (item1 != null && item2 != null) {
                 return item1.app_category.name.collate (item2.app_category.name);
             }
@@ -99,7 +95,6 @@
         foreach (var app in apps) {
             app_list_view.add_package (app);
         }
-
     }
 
     private void get_app_categories () {
@@ -121,9 +116,11 @@
         var category = new AppStream.Category ();
         category.set_name (_("Audio"));
         category.set_icon ("applications-audio-symbolic");
+
         var categories = new Gee.LinkedList<string> ();
         categories.add ("Audio");
         category.set_data<Gee.LinkedList> ("categories", categories);
+
         var item = new Widgets.CategoryItem (category);
         item.add_category_class ("audio");
 
@@ -133,10 +130,12 @@
     private Widgets.CategoryItem get_development_category () {
         var category = new AppStream.Category ();
         category.set_name (_("Development"));
+
         var categories = new Gee.LinkedList<string> ();
         categories.add ("Development");
         categories.add ("IDE");
         category.set_data<Gee.LinkedList> ("categories", categories);
+
         var item = new Widgets.CategoryItem (category);
         item.add_category_class ("development");
 
@@ -147,9 +146,11 @@
         var category = new AppStream.Category ();
         category.set_name (_("Accessories"));
         category.set_icon ("applications-accessories");
+
         var categories = new Gee.LinkedList<string> ();
         categories.add ("Utility");
         category.set_data<Gee.LinkedList> ("categories", categories);
+
         var item = new Widgets.CategoryItem (category);
         item.add_category_class ("accessories");
 
@@ -160,9 +161,11 @@
         var category = new AppStream.Category ();
         category.set_name (_("Office"));
         category.set_icon ("applications-office-symbolic");
+
         var categories = new Gee.LinkedList<string> ();
         categories.add ("Office");
         category.set_data<Gee.LinkedList> ("categories", categories);
+
         var item = new Widgets.CategoryItem (category);
         item.add_category_class ("office");
 
@@ -173,9 +176,11 @@
         var category = new AppStream.Category ();
         category.set_name (_("System"));
         category.set_icon ("applications-system");
+
         var categories = new Gee.LinkedList<string> ();
         categories.add ("System");
         category.set_data<Gee.LinkedList> ("categories", categories);
+
         var item = new Widgets.CategoryItem (category);
         item.add_category_class ("system");
 
@@ -186,9 +191,11 @@
         var category = new AppStream.Category ();
         category.set_name (_("Video"));
         category.set_icon ("applications-video-symbolic");
+
         var categories = new Gee.LinkedList<string> ();
         categories.add ("Video");
         category.set_data<Gee.LinkedList> ("categories", categories);
+
         var item = new Widgets.CategoryItem (category);
         item.add_category_class ("video");
 
@@ -198,9 +205,11 @@
     private Widgets.CategoryItem get_graphics_category () {
         var category = new AppStream.Category ();
         category.set_name (_("Graphics"));
+
         var categories = new Gee.LinkedList<string> ();
         categories.add ("Graphics");
         category.set_data<Gee.LinkedList> ("categories", categories);
+
         var item = new Widgets.CategoryItem (category);
         item.add_category_class ("graphics");
 
@@ -210,10 +219,12 @@
     private Widgets.CategoryItem get_games_category () {
         var category = new AppStream.Category ();
         category.set_name (_("Games"));
+
         var categories = new Gee.LinkedList<string> ();
         categories.add ("Game");
         category.set_data<Gee.LinkedList> ("categories", categories);
         category.set_icon ("applications-games-symbolic");
+
         var item = new Widgets.CategoryItem (category);
         item.add_category_class ("games");
 
@@ -223,9 +234,11 @@
     private Widgets.CategoryItem get_education_category () {
         var category = new AppStream.Category ();
         category.set_name (_("Education"));
+
         var categories = new Gee.LinkedList<string> ();
         categories.add ("Education");
         category.set_data<Gee.LinkedList> ("categories", categories);
+
         var item = new Widgets.CategoryItem (category);
         item.add_category_class ("education");
 
@@ -236,9 +249,11 @@
         var category = new AppStream.Category ();
         category.set_name (_("Internet"));
         category.set_icon ("applications-internet");
+
         var categories = new Gee.LinkedList<string> ();
         categories.add ("Network");
         category.set_data<Gee.LinkedList> ("categories", categories);
+
         var item = new Widgets.CategoryItem (category);
         item.add_category_class ("internet");
 
@@ -248,9 +263,11 @@
     private Widgets.CategoryItem get_science_category () {
         var category = new AppStream.Category ();
         category.set_name (_("Science & Engineering"));
+
         var categories = new Gee.LinkedList<string> ();
         categories.add ("Science");
         category.set_data<Gee.LinkedList> ("categories", categories);
+
         var item = new Widgets.CategoryItem (category);
         item.add_category_class ("science");
 
@@ -261,9 +278,11 @@
         var category = new AppStream.Category ();
         category.set_name (_("Universal Access"));
         category.set_icon ("applications-accessibility-symbolic");
+
         var categories = new Gee.LinkedList<string> ();
         categories.add ("Accessibility");
         category.set_data<Gee.LinkedList> ("categories", categories);
+
         var item = new Widgets.CategoryItem (category);
         item.add_category_class ("accessibility");
 

=== modified file 'src/Views/FeaturedView.vala'
--- src/Views/FeaturedView.vala	2015-10-30 17:53:09 +0000
+++ src/Views/FeaturedView.vala	2016-10-13 21:30:22 +0000
@@ -21,7 +21,7 @@
 using AppCenterCore;
 
 public class AppCenter.Views.FeaturedView : Gtk.Grid {
-    public FeaturedView () {
+    construct {
         halign = Gtk.Align.CENTER;
         column_homogeneous = true;
         column_spacing = 6;
@@ -39,7 +39,7 @@
         attach (left_featured, 0, 0, 1, 1);
         attach (right_featured, 1, 0, 1, 1);
         attach (rated_label, 0, 1, 1, 1);
-        attach (latest_label, 1, 1, 1, 1);
+        attach (latest_label, 1, 1, 1, 1);        
     }
 
     private Gtk.Widget get_left_placeholder () {

=== modified file 'src/Views/InstalledView.vala'
--- src/Views/InstalledView.vala	2016-09-22 14:10:06 +0000
+++ src/Views/InstalledView.vala	2016-10-13 21:30:22 +0000
@@ -21,22 +21,7 @@
 using AppCenterCore;
 
 public class AppCenter.Views.InstalledView : View {
-    AppListUpdateView app_list_view;
-
-    public InstalledView () {
-        var client = Client.get_default ();
-        // We need this line in order to show the No Update view.
-        client.updates_available.connect (() => {
-            var package = Client.get_default ().os_updates;
-            if (package.update_available) {
-                app_list_view.add_package (package);
-            }
-
-            app_list_view.updating_cache = false;
-        });
-
-        client.bind_property ("updating-cache", app_list_view, "updating-cache", GLib.BindingFlags.DEFAULT);
-    }
+    private AppListUpdateView app_list_view;
 
     construct {
         app_list_view = new AppListUpdateView ();
@@ -45,6 +30,21 @@
             subview_entered (C_("view", "Updates"), false);
             show_package (package);
         });
+
+        unowned AppCenterCore.Client client = Client.get_default ();
+        client.bind_property ("updating-cache", app_list_view, "updating-cache", GLib.BindingFlags.DEFAULT);
+
+        // We need this line in order to show the No Update view.
+        client.updates_available.connect (on_updates_available);
+    }
+
+    private void on_updates_available (AppCenterCore.Client client) {
+        var package = client.os_updates;
+        if (package.update_available) {
+            app_list_view.add_package (package);
+        }
+
+        app_list_view.updating_cache = false;
     }
 
     public override void return_clicked () {
@@ -64,6 +64,7 @@
 
     public async void add_app (AppCenterCore.Package package) {
         unowned Client client = Client.get_default ();
+
         var installed_apps = yield client.get_installed_applications ();
         foreach (var app in installed_apps) {
             if (app == package) {

=== modified file 'src/Views/SearchView.vala'
--- src/Views/SearchView.vala	2016-10-07 17:58:37 +0000
+++ src/Views/SearchView.vala	2016-10-13 21:30:22 +0000
@@ -21,21 +21,19 @@
 using AppCenterCore;
 
 public class AppCenter.Views.SearchView : View {
-    const int MAX_NUMBER_OF_SEARCH_RESULTS = 100;
-    AppListView app_list_view;
-
-    public SearchView () {
-        
-    }
+    private const int MAX_NUMBER_OF_SEARCH_RESULTS = 100;
+    private AppListView app_list_view;
 
     construct {
         app_list_view = new AppListView ();
         add (app_list_view);
-        app_list_view.show_app.connect ((package) => {
-            /// TRANSLATORS: the name of the Search view
-            subview_entered (C_("view", "Search"), false);
-            show_package (package);
-        });
+        app_list_view.show_app.connect (on_show_app);
+    }
+
+    private void on_show_app (AppCenterCore.Package package) {
+        /// TRANSLATORS: the name of the Search view
+        subview_entered (C_("view", "Search"), false);
+        show_package (package);        
     }
 
     public override void return_clicked () {
@@ -44,17 +42,20 @@
     
     public async void search (string search_term, AppStream.Category? category) {
         app_list_view.clear ();
+
         unowned Client client = Client.get_default ();
         var found_apps = client.search_applications (search_term, category);
         
-        if (found_apps.size > 0) {
-            var apps_array = found_apps.to_array ();
-            int i = 0;
-            while (i < apps_array.length && i < MAX_NUMBER_OF_SEARCH_RESULTS) {
-                var app = apps_array[i];
-                app_list_view.add_package (app);
-                i++;   
-            }
+        if (found_apps.size <= 0) {
+            return;
+        }
+
+        var apps_array = found_apps.to_array ();
+        int i = 0;
+        while (i < apps_array.length && i < MAX_NUMBER_OF_SEARCH_RESULTS) {
+            var app = apps_array[i];
+            app_list_view.add_package (app);
+            i++;   
         }
     }
 }

=== modified file 'src/Views/View.vala'
--- src/Views/View.vala	2016-09-22 14:10:06 +0000
+++ src/Views/View.vala	2016-10-13 21:30:22 +0000
@@ -30,14 +30,15 @@
     public void show_package (AppCenterCore.Package package) {
         var pk_child = get_child_by_name (package.component.id);
         if (pk_child != null) {
-            set_visible_child (pk_child);
+            visible_child = pk_child;
             return;
         }
 
         var app_info_view = new Views.AppInfoView (package);
         app_info_view.show_all ();
         add_named (app_info_view, package.component.id);
-        set_visible_child (app_info_view);
+        visible_child = app_info_view;
+
         Timeout.add (transition_duration, () => {
             app_info_view.load_more_content ();
             return Source.REMOVE;

=== modified file 'src/Widgets/AppActionButton.vala'
--- src/Widgets/AppActionButton.vala	2016-09-01 09:30:52 +0000
+++ src/Widgets/AppActionButton.vala	2016-10-13 21:30:22 +0000
@@ -20,21 +20,18 @@
 
 namespace AppCenter.Widgets {
     public class AppActionButton : Gtk.Button {
-        public AppActionButton (string? _label) {
+        construct {
             valign = Gtk.Align.CENTER;
+        }
+
+        public AppActionButton (string? _label, string? style_class = null) {
             label = _label;
-         }
-
-        public void set_suggested_action_header () {
-            var style_ctx = get_style_context ();
-            style_ctx.add_class (Gtk.STYLE_CLASS_SUGGESTED_ACTION);
-            style_ctx.add_class ("h3");
-        }
-
-        public void set_destructive_action_header () {
-            var style_ctx = get_style_context ();
-            style_ctx.add_class (Gtk.STYLE_CLASS_DESTRUCTIVE_ACTION);
-            style_ctx.add_class ("h3");
+
+            if (style_class != null) {
+                var style_context = get_style_context ();
+                style_context.add_class (style_class);
+                style_context.add_class ("h3");
+            }
         }
      }
 }

=== modified file 'src/Widgets/AppCellRenderer.vala'
--- src/Widgets/AppCellRenderer.vala	2015-11-17 18:35:04 +0000
+++ src/Widgets/AppCellRenderer.vala	2016-10-13 21:30:22 +0000
@@ -21,37 +21,35 @@
 using AppCenterCore;
 
 public class AppCenter.Widgets.AppCellRenderer : Gtk.CellRenderer {
+    private const int MARGIN = 6;
+    private const int ICON_SIZE = 48;
+    private const int ACTION_ICON_SIZE = 24;
 
     /* icon property set by the tree column */
     public AppCenterCore.Package package { get; set; }
     public Gdk.Pixbuf icon { get; set; }
 
     private Gdk.Pixbuf update_icon;
-    private const int MARGIN = 6;
-    private const int ICON_SIZE = 48;
-    private const int ACTION_ICON_SIZE = 24;
     private Gtk.Label title_label;
     private Gtk.Label summary_label;
 
-    public AppCellRenderer () {
-        
-    }
-
     construct {
         title_label = new Gtk.Label (null);
         title_label.get_style_context ().add_class ("h3");
+
         summary_label = new Gtk.Label (null);
+
         try {
             update_icon = Gtk.IconTheme.get_default ().load_icon ("software-update-available-symbolic", ACTION_ICON_SIZE, Gtk.IconLookupFlags.GENERIC_FALLBACK);
         } catch (Error e) {
-            critical (e.message);
+            warning (e.message);
         }
     }
 
     public override void get_size (Gtk.Widget widget, Gdk.Rectangle? cell_area, out int x_offset, out int y_offset, out int width, out int height) {
         x_offset = 0;
         y_offset = 0;
-        width = 50;
+        width = ICON_SIZE + 2;
         height = ICON_SIZE + 2 * MARGIN;
     }
 
@@ -104,13 +102,16 @@
 
     private void draw_label (Cairo.Context cr, Gtk.Widget widget, Gtk.Label label, int x, int y, string title, int width, out int height) {
         cr.save ();
+
         var style_context = widget.get_style_context ();
+
         var label_style_context = label.get_style_context ();
         label_style_context.parent = style_context.parent;
         label_style_context.set_state (style_context.get_state ());
 
         var label_layout = label.create_pango_layout (title);
         label_layout.set_width (width * Pango.SCALE);
+
         if (style_context.direction == Gtk.TextDirection.RTL) {
             label_layout.set_ellipsize (Pango.EllipsizeMode.START);
             label_layout.set_alignment (Pango.Alignment.RIGHT);
@@ -122,6 +123,7 @@
         int label_width;
         label_layout.get_pixel_size (out label_width, out height);
         label_style_context.render_layout (cr, x, y, label_layout);
+        
         cr.restore ();
     }
 

=== modified file 'src/Widgets/AppListRow.vala'
--- src/Widgets/AppListRow.vala	2016-09-17 19:28:03 +0000
+++ src/Widgets/AppListRow.vala	2016-10-13 21:30:22 +0000
@@ -24,8 +24,12 @@
     public interface AppListRow : Gtk.ListBoxRow {
         public abstract bool get_update_available ();
         public abstract bool get_is_os_updates ();
-        public abstract string get_name_label ();
-        public abstract bool has_package ();
+        public abstract string? get_name_label ();
+        
+        public bool has_package () {
+            return get_package () != null;
+        }
+
         public abstract AppCenterCore.Package? get_package ();
     }
 }

=== modified file 'src/Widgets/CategoryItem.vala'
--- src/Widgets/CategoryItem.vala	2016-07-11 19:13:28 +0000
+++ src/Widgets/CategoryItem.vala	2016-10-13 21:30:22 +0000
@@ -18,7 +18,7 @@
  * Authored by: Corentin Noël <[e-mail]>
  */
 
-const string CATEGORIES_STYLE_CSS = """
+public const string CATEGORIES_STYLE_CSS = """
     .category {
         background-image: linear-gradient(to bottom,
                                   #fafafa,
@@ -233,16 +233,6 @@
         show_all ();
     }
 
-    static construct {
-        var provider = new Gtk.CssProvider ();
-        try {
-            provider.load_from_data (CATEGORIES_STYLE_CSS, CATEGORIES_STYLE_CSS.length);
-            Gtk.StyleContext.add_provider_for_screen (Gdk.Screen.get_default (), provider, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
-        } catch (Error e) {
-            critical (e.message);
-        }
-    }
-
     construct {
         grid = new Gtk.Grid ();
         grid.orientation = Gtk.Orientation.HORIZONTAL;

=== modified file 'src/Widgets/FeaturedButton.vala'
--- src/Widgets/FeaturedButton.vala	2015-11-13 02:43:52 +0000
+++ src/Widgets/FeaturedButton.vala	2016-10-13 21:30:22 +0000
@@ -37,22 +37,22 @@
     .featured:dir(rtl) {
         background: linear-gradient(to right,rgba(255, 255, 255, 0.3), rgba(255, 255, 255, 0));
     }
-    """;
+""";
 
 const string COLORED_STYLE_CSS = """
     .colored {
         color: %s;
     }
-    """;
+""";
 
 public class AppCenter.Widgets.FeaturedButton : Gtk.Grid {
     public signal void clicked ();
-    Gdk.RGBA background_color;
+    private Gdk.RGBA background_color;
 
-    Gtk.Label title_label;
-    Gtk.Label summary_label;
-    Gtk.Image icon_image;
-    const int MARGIN = 6;
+    private Gtk.Label title_label;
+    private Gtk.Label summary_label;
+    private Gtk.Image icon_image;
+    private const int MARGIN = 6;
 
     public FeaturedButton (Gdk.RGBA background_color, Gdk.RGBA text_color, string title, string summary, GLib.Icon icon) {
         this.background_color = background_color;
@@ -61,17 +61,20 @@
         icon_image.gicon = icon;
 
         var provider = new Gtk.CssProvider ();
+
         try {
             var colored_css = COLORED_STYLE_CSS.printf (text_color.to_string ());
             provider.load_from_data (colored_css, colored_css.length);
-            var context = title_label.get_style_context ();
-            context.add_provider (provider, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
-            context.add_class ("colored");
-            context = summary_label.get_style_context ();
-            context.add_provider (provider, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
-            context.add_class ("colored");
+
+            var style_context = title_label.get_style_context ();
+            style_context.add_provider (provider, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
+            style_context.add_class ("colored");
+
+            style_context = summary_label.get_style_context ();
+            style_context.add_provider (provider, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
+            style_context.add_class ("colored");
         } catch (GLib.Error e) {
-            critical (e.message);
+            warning (e.message);
         }
     }
 
@@ -104,12 +107,13 @@
         attach (title_label, 1, 0, 1, 1);
         attach (summary_label, 1, 1, 1, 1);
 
-        var context = get_style_context ();
+        var style_context = get_style_context ();
         var provider = new Gtk.CssProvider ();
+
         try {
             provider.load_from_data (FEATURED_STYLE_CSS, FEATURED_STYLE_CSS.length);
-            context.add_provider(provider, Gtk.STYLE_PROVIDER_PRIORITY_FALLBACK);
-            context.add_class ("featured");
+            style_context.add_provider (provider, Gtk.STYLE_PROVIDER_PRIORITY_FALLBACK);
+            style_context.add_class ("featured");
         } catch (GLib.Error e) {
             critical (e.message);
         }
@@ -117,8 +121,8 @@
 
     public override void get_preferred_height (out int minimum_height, out int natural_height) {
         base.get_preferred_height (out minimum_height, out natural_height);
-        minimum_height += 2*MARGIN;
-        natural_height += 2*MARGIN;
+        minimum_height += 2 * MARGIN;
+        natural_height += 2 * MARGIN;
         if (natural_height < 100) {
             natural_height = 100;
         }
@@ -126,8 +130,8 @@
 
     public override void get_preferred_width (out int minimum_width, out int natural_width) {
         base.get_preferred_width (out minimum_width, out natural_width);
-        minimum_width += 2*MARGIN;
-        natural_width += 2*MARGIN;
+        minimum_width += 2 * MARGIN;
+        natural_width += 2 * MARGIN;
         if (natural_width < 350) {
             natural_width = 350;
         }
@@ -138,16 +142,17 @@
         return false;
     }
 
-
     public override bool draw (Cairo.Context cr) {
         int width = get_allocated_width ();
         int height = get_allocated_height ();
 
         cr.save ();
         cr.set_source_rgba (background_color.red, background_color.green, background_color.blue, background_color.alpha);
+        
         int x = 0;
         int y = 0;
         double radius = 3;
+
         cr.move_to (x + radius, y);
         cr.arc (x + width - radius, y + radius, radius, Math.PI * 1.5, Math.PI * 2);
         cr.arc (x + width - radius, y + height - radius, radius, 0, Math.PI_2);

=== modified file 'src/Widgets/PackageRow.vala'
--- src/Widgets/PackageRow.vala	2016-09-17 19:28:03 +0000
+++ src/Widgets/PackageRow.vala	2016-10-13 21:30:22 +0000
@@ -20,14 +20,13 @@
 
 namespace AppCenter.Widgets {
     public class PackageRow : Gtk.ListBoxRow, AppListRow {
-        PackageRowGrid grid;
+        private PackageRowGrid grid;
 
         public PackageRow (AppCenterCore.Package package, Gtk.SizeGroup? size_group, bool show_uninstall = true) {
             grid = new PackageRowGrid (package, size_group, show_uninstall);
+            grid.changed.connect (() => changed ());
+
             add (grid);
-            grid.changed.connect (() => {
-                changed ();
-            });
         }
 
         public bool get_update_available () {
@@ -42,7 +41,7 @@
             return grid.is_os_updates;
         }
 
-        public string get_name_label () {
+        public string? get_name_label () {
             return grid.name_label;
         }
 
@@ -55,7 +54,7 @@
         }
 
         public bool has_package () {
-            return true;
+            return grid.package != null;
         }
 
         private class PackageRowGrid : AbstractAppContainer {
@@ -68,24 +67,21 @@
                 column_spacing = 12;
                 row_spacing = 6;
 
-                image = new Gtk.Image ();
                 image.icon_size = Gtk.IconSize.DIALOG;
+
                 /* Needed to enforce size on icons from Filesystem/Remote */
                 image.pixel_size = 48;
 
-                package_name = new Gtk.Label (null);
                 package_name.get_style_context ().add_class ("h3");
                 package_name.hexpand = true;
                 package_name.valign = Gtk.Align.END;
                 ((Gtk.Misc) package_name).xalign = 0;
 
-                package_summary = new Gtk.Label (null);
                 package_summary.get_style_context ().add_class (Gtk.STYLE_CLASS_DIM_LABEL);
                 package_summary.hexpand = true;
                 package_summary.valign = Gtk.Align.START;
                 ((Gtk.Misc) package_summary).xalign = 0;
 
-
                 attach (image, 0, 0, 1, 2);
                 attach (package_name, 1, 0, 1, 1);
                 attach (package_summary, 1, 1, 1, 1);
@@ -93,9 +89,8 @@
             }
 
             public PackageRowGrid (AppCenterCore.Package package, Gtk.SizeGroup? size_group, bool show_uninstall = true) {
-                this.package = package;
+                Object (package: package);
                 this.show_uninstall = show_uninstall;
-                set_up_package ();
 
                 if (size_group != null) {
                     size_group.add_widget (action_button);

=== modified file 'src/Widgets/UpdateHeaderRow.vala'
--- src/Widgets/UpdateHeaderRow.vala	2016-09-17 19:28:03 +0000
+++ src/Widgets/UpdateHeaderRow.vala	2016-10-13 21:30:22 +0000
@@ -20,24 +20,26 @@
 
 namespace AppCenter.Widgets {
     public class UpdateHeaderRow : Gtk.ListBoxRow, AppListRow {
-        AbstractHeaderGrid grid;
-        public bool is_updates_header {get; private set;}
+        public bool is_updates_header { get; private set; }
+        private AbstractHeaderGrid grid;
 
         construct {
-            set_activatable (false);
-            set_selectable (false);
+            activatable = false;
+            selectable = false;
         }
 
         public UpdateHeaderRow.updates () {
+            is_updates_header = true;
+
             grid = new UpdatesGrid ();
             add (grid);
-            is_updates_header = true;
         }
 
         public UpdateHeaderRow.updated () {
+            is_updates_header = false;
+
             grid = new UpdatedGrid ();
             add (grid);
-            is_updates_header = false;
         }
 
         /** AppListRow Interface methods **/
@@ -49,21 +51,17 @@
         }
 
         public bool get_is_os_updates () {
-            critical ("Must not attempt to get is_os_update from header row");
-            assert_not_reached ();
+            warning ("Must not attempt to get is_os_update from header row");
+            return false;
         }
 
-        /* This indicates it is a header row, not a package row */
-        public bool has_package () {return false;}
-
         public AppCenterCore.Package? get_package () {
-            critical ("Must not attempt to get package from header row");
-            assert_not_reached ();
+            return null;
         }
 
-        public string get_name_label () {
-            critical ("Must not attempt to get package name from header row");
-            assert_not_reached ();
+        public string? get_name_label () {
+            warning ("Must not attempt to get package name from header row");
+            return null;
         }
 
         public void add_widget (Gtk.Widget widget) {
@@ -74,26 +72,23 @@
             grid.update (_update_numbers, _update_real_size, _is_updating);
             changed (); /* Triggers resort */
         }
-        /** ---------------- **/
 
         /** Base class for Grids in Header Rows **/
         private abstract class AbstractHeaderGrid : Gtk.Grid {
-            public uint update_numbers {get; protected set; default = 0;}
-            public uint64 update_real_size {get; protected set; default = 0;}
-            public bool is_updating {get; protected set; default = false;}
+            public uint update_numbers { get; set; default = 0; }
+            public uint64 update_real_size { get; set; default = 0; }
+            public bool is_updating { get; set; default = false; }
 
             construct {
                 margin = 12;
                 column_spacing = 12;
             }
 
-            protected void store_data (uint _update_numbers, uint64 _update_real_size, bool _is_updating) {
+            public virtual void update (uint _update_numbers, uint64 _update_real_size, bool _is_updating) {
                 update_numbers = _update_numbers;
                 update_real_size = _update_real_size;
                 is_updating = _is_updating;
             }
-
-            public abstract void update (uint _update_numbers, uint64 _update_real_size, bool _is_updating);
         }
 
         /** Header to show at top of list if there are updates available **/
@@ -115,7 +110,7 @@
             }
 
             public override void update (uint _update_numbers, uint64 _update_real_size, bool _is_updating) {
-                store_data (_update_numbers,  _update_real_size, _is_updating);
+                base.update (_update_numbers, _update_real_size, _is_updating);
 
                 if (!is_updating) {
                     updates_label.label = ngettext ("%u Update Available", "%u Updates Available", update_numbers).printf (update_numbers);
@@ -137,9 +132,9 @@
             private Gtk.Spinner spinner;
 
             construct {
-                label = new Gtk.Label (""); /* Should not be displayed before being updated */
+                label = new Gtk.Label (null); /* Should not be displayed before being updated */
                 label.hexpand = true;
-                ((Gtk.Misc)label).xalign = 0;
+                ((Gtk.Misc) label).xalign = 0;
 
                 spinner = new Gtk.Spinner ();
 
@@ -148,20 +143,18 @@
             }
 
             public override void update (uint _update_numbers, uint64 _update_real_size, bool _is_updating) {
-                store_data (_update_numbers,  _update_real_size, _is_updating);
-
+                base.update (_update_numbers, _update_real_size, _is_updating);
+                
                 if (is_updating) {
                     halign = Gtk.Align.CENTER;
                     spinner.start ();
-                    spinner.no_show_all = false;
-                    spinner.show ();
+                    set_widget_visible (spinner, true);
                     label.label = _("Searching for updates…");
                     label.get_style_context ().remove_class ("h4");
                 } else {
                     halign = Gtk.Align.START;
                     spinner.stop ();
-                    spinner.no_show_all = true;
-                    spinner.hide ();
+                    set_widget_visible (spinner, false);
                     label.label = _("Up to Date");
                     label.get_style_context ().add_class ("h4");
                 }