Size loaded item before bindings are evaluated

If the Loader size is set explicitly we can set the item size
before the bindings are run, and avoiding an additional
anchor layout.

Also ensure item implict size changes are propagated/notified in the
Loader.

Change-Id: Ie22b018b22be8457ccf30b907a26e44260b9cef7
Reviewed-by: Michael Brasser <michael.brasser@nokia.com>

1 files changed, 52 insertions, 19 deletions

diff --git a/src/quick/items/qquickloader.cpp b/src/quick/items/qquickloader.cpp
index f41ba44943..730dfd45d4 100644
--- a/src/quick/items/qquickloader.cpp
+++ b/src/quick/items/qquickloader.cpp
@@ -52,9 +52,11 @@
 
 QT_BEGIN_NAMESPACE
 
+static const QQuickItemPrivate::ChangeTypes watchedChanges
+    = QQuickItemPrivate::Geometry | QQuickItemPrivate::ImplicitWidth | QQuickItemPrivate::ImplicitHeight;
+
 QQuickLoaderPrivate::QQuickLoaderPrivate()
     : item(0), component(0), itemContext(0), incubator(0), updatingSize(false),
-      itemWidthValid(false), itemHeightValid(false),
       active(true), loadingFromSource(false), asynchronous(false)
 {
 }
@@ -69,16 +71,23 @@ QQuickLoaderPrivate::~QQuickLoaderPrivate()
 
 void QQuickLoaderPrivate::itemGeometryChanged(QQuickItem *resizeItem, const QRectF &newGeometry, const QRectF &oldGeometry)
 {
-    if (resizeItem == item) {
-        if (!updatingSize && newGeometry.width() != oldGeometry.width())
-            itemWidthValid = true;
-        if (!updatingSize && newGeometry.height() != oldGeometry.height())
-            itemHeightValid = true;
+    if (resizeItem == item)
         _q_updateSize(false);
-    }
     QQuickItemChangeListener::itemGeometryChanged(resizeItem, newGeometry, oldGeometry);
 }
 
+void QQuickLoaderPrivate::itemImplicitWidthChanged(QQuickItem *)
+{
+    Q_Q(QQuickLoader);
+    q->setImplicitWidth(getImplicitWidth());
+}
+
+void QQuickLoaderPrivate::itemImplicitHeightChanged(QQuickItem *)
+{
+    Q_Q(QQuickLoader);
+    q->setImplicitHeight(getImplicitHeight());
+}
+
 void QQuickLoaderPrivate::clear()
 {
     Q_Q(QQuickLoader);
@@ -103,7 +112,7 @@ void QQuickLoaderPrivate::clear()
 
     if (item) {
         QQuickItemPrivate *p = QQuickItemPrivate::get(item);
-        p->removeItemChangeListener(this, QQuickItemPrivate::Geometry);
+        p->removeItemChangeListener(this, watchedChanges);
 
         // We can't delete immediately because our item may have triggered
         // the Loader to load a different item.
@@ -117,14 +126,32 @@ void QQuickLoaderPrivate::clear()
 void QQuickLoaderPrivate::initResize()
 {
     QQuickItemPrivate *p = QQuickItemPrivate::get(item);
-    p->addItemChangeListener(this, QQuickItemPrivate::Geometry);
-    // We may override the item's size, so we need to remember
-    // whether the item provided its own valid size.
-    itemWidthValid = p->widthValid;
-    itemHeightValid = p->heightValid;
+    p->addItemChangeListener(this, watchedChanges);
     _q_updateSize();
 }
 
+qreal QQuickLoaderPrivate::getImplicitWidth() const
+{
+    Q_Q(const QQuickLoader);
+    // If the Loader has a valid width then Loader has set an explicit width on the
+    // item, and we want the item's implicitWidth.  If the Loader's width has
+    // not been set then its implicitWidth is the width of the item.
+    if (item)
+        return q->widthValid() ? item->implicitWidth() : item->width();
+    return QQuickImplicitSizeItemPrivate::getImplicitWidth();
+}
+
+qreal QQuickLoaderPrivate::getImplicitHeight() const
+{
+    Q_Q(const QQuickLoader);
+    // If the Loader has a valid height then Loader has set an explicit height on the
+    // item, and we want the item's implicitHeight.  If the Loader's height has
+    // not been set then its implicitHeight is the height of the item.
+    if (item)
+        return q->heightValid() ? item->implicitHeight() : item->height();
+    return QQuickImplicitSizeItemPrivate::getImplicitHeight();
+}
+
 /*!
     \qmlclass Loader QQuickLoader
     \inqmlmodule QtQuick 2
@@ -245,7 +272,7 @@ QQuickLoader::~QQuickLoader()
     Q_D(QQuickLoader);
     if (d->item) {
         QQuickItemPrivate *p = QQuickItemPrivate::get(d->item);
-        p->removeItemChangeListener(d, QQuickItemPrivate::Geometry);
+        p->removeItemChangeListener(d, watchedChanges);
     }
 }
 
@@ -284,7 +311,7 @@ void QQuickLoader::setActive(bool newVal)
         } else {
             if (d->item) {
                 QQuickItemPrivate *p = QQuickItemPrivate::get(d->item);
-                p->removeItemChangeListener(d, QQuickItemPrivate::Geometry);
+                p->removeItemChangeListener(d, watchedChanges);
 
                 // We can't delete immediately because our item may have triggered
                 // the Loader to load a different item.
@@ -553,6 +580,14 @@ void QQuickLoaderPrivate::setInitialState(QObject *obj)
 
     QQuickItem *item = qobject_cast<QQuickItem*>(obj);
     if (item) {
+        // If the item doesn't have an explicit size, but the Loader
+        // does, then set the item's size now before bindings are
+        // evaluated, otherwise we will end up resizing the item
+        // later and triggering any affected bindings/anchors.
+        if (widthValid && !QQuickItemPrivate::get(item)->widthValid)
+            item->setWidth(q->width());
+        if (heightValid && !QQuickItemPrivate::get(item)->heightValid)
+            item->setHeight(q->height());
         QQml_setParent_noEvent(itemContext, obj);
         QQml_setParent_noEvent(item, q);
         item->setParentItem(q);
@@ -812,15 +847,13 @@ void QQuickLoaderPrivate::_q_updateSize(bool loaderGeometryChanged)
 
     updatingSize = true;
 
-    qreal iWidth = !itemWidthValid ? item->implicitWidth() : item->width();
-    qreal iHeight = !itemHeightValid ? item->implicitHeight() : item->height();
-    q->setImplicitSize(iWidth, iHeight);
-
     if (loaderGeometryChanged && q->widthValid())
         item->setWidth(q->width());
     if (loaderGeometryChanged && q->heightValid())
         item->setHeight(q->height());
 
+    q->setImplicitSize(getImplicitWidth(), getImplicitHeight());
+
     updatingSize = false;
 }