Merge lp:~ahayzen/music-app/columnflow-fixes-and-preloading-support into lp:music-app/remix

[Andrew Hayzen]

* Fixes and add preloading compatibility to ColumnFlow.qml

* Fixes and add preloading compatibility to ColumnFlow.qml

Preloading is disable for now until we load the pages in async and the thumbnailer is fast enough :)

[Ubuntu Phone Apps Jenkins Bot (ubuntu-phone-apps-jenkins-bot)]

PASSED: Continuous integration, rev:863
http://91.189.93.70:8080/job/music-app-ci/1299/
Executed test runs:
    SUCCESS: http://91.189.93.70:8080/job/generic-mediumtests-utopic/2697
        deb: http://91.189.93.70:8080/job/generic-mediumtests-utopic/2697/artifact/work/output/*zip*/output.zip
    SUCCESS: http://91.189.93.70:8080/job/music-app-utopic-amd64-ci/393
    SUCCESS: http://91.189.93.70:8080/job/music-app-vivid-amd64-ci/151

Click here to trigger a rebuild:
http://91.189.93.70:8080/job/music-app-ci/1299/rebuild

review: Approve (continuous-integration)

[Victor Thompson (vthompson)]

lgtm!

review: Approve

=== modified file 'common/ColumnFlow.qml'
--- common/ColumnFlow.qml	2015-01-11 17:40:13 +0000
+++ common/ColumnFlow.qml	2015-05-02 17:50:36 +0000
@@ -40,6 +40,8 @@
     property bool removing: false
     property bool restoring: false  // is the view restoring?
     property var restoreItems: ({})  // when rebuilding items are stored here temporarily
+    // Disable preloading for now until async loading of pages is implemented
+    property bool preloading: true  // when visible has only been false allow loading (as no child objects [eg pages] can have been created on the fly)
 
     onColumnWidthChanged: {
         if (restoring) {
@@ -62,6 +64,10 @@
     }
 
     onVisibleChanged: {
+        if (visible) {
+            preloading = false;
+        }
+
         if (visible && delayRebuildIndex !== -1) {  // restore from count change
             if (delayRebuildIndex === 0) {
                 reset()
@@ -86,7 +92,7 @@
     Connections {
         target: model === undefined ? fakeModel : model
         onModelReset: {
-            if (!visible) {
+            if (!visible && lastIndex > 0 && !preloading) {
                 delayRebuildIndex = 0
             } else {
                 reset()
@@ -94,7 +100,7 @@
             }
         }
         onRowsInserted: {
-            if (!visible) {
+            if (!visible && lastIndex > 0 && !preloading) {
                 setDelayRebuildIndex(first)
             } else {
                 if (first <= lastIndex) {
@@ -161,7 +167,8 @@
             // and
             // allow if the y position is within the viewport
             // or if loadBefore is true then allow if the y position is before the viewport
-            if (((count > 0 && lastIndex < count && insertMax === undefined) || (insertMax !== undefined && lastIndex <= insertMax)) && (inViewport(y, 0) || (loadBefore === true && beforeViewport(y)))) {
+            if (((count > 0 && lastIndex < count && insertMax === undefined) || (insertMax !== undefined && lastIndex <= insertMax))
+                    && (inViewport(y, 0) || (loadBefore === true && beforeViewport(y)))) {
                 incubateObject(lastIndex++, columnsByHeight[i], getMaxInColumn(columnsByHeight[i]), append);
                 workDone = true
             } else {
@@ -489,4 +496,15 @@
             delayRebuildIndex = index
         }
     }
+
+    Component.onCompleted: {
+        // Ensure that initial column vars are set
+        for (var j=0; j < columns; j++) {
+            columnHeights.push({})
+        }
+
+        cacheColumnHeights()
+
+        append(true)
+    }
 }