Improve emission of FocusScope focusChanged signals.

Emit activeFocusChanged up the focus tree when an item receives a focus
event, rather than when the focusItem changes which happens before
internal state is sufficiently updated for hasFocus and hasActiveFocus
to return the correct values from within a changed signal handler.

There are some limitions to this. First the signals are not emitted
reliably when the scene is not active which makes sense for activeFocus
but not for focus.  The second is in some instances the focus and
activeFocus can update unnecessarily while the focus chain sorts itself
out.

QDeclarativeItem tests by Andreas Aardal Hanssen <andreas@hanssen.name>

Task-number: QTBUG-28288
Task-number: QTBUG-25644
(cherry picked from qtquick1/c520a69f06317fb90d37324bf284ef9614cb5dbf)

Change-Id: Iac12bf8c95cbf3525b454f4afca06a54a5c14b4e
Reviewed-by: Andreas Aardal Hanssen <andreas@hanssen.name>
Reviewed-by: Andrew den Exter <andrew.den.exter@qinetic.com.au>

2 files changed, 29 insertions, 18 deletions

diff --git a/src/declarative/graphicsitems/qdeclarativeitem.cpp b/src/declarative/graphicsitems/qdeclarativeitem.cpp
index d3636ed9c5..e0e368f471 100644
--- a/src/declarative/graphicsitems/qdeclarativeitem.cpp
+++ b/src/declarative/graphicsitems/qdeclarativeitem.cpp
@@ -2740,9 +2740,27 @@ QDeclarativeItem *QDeclarativeItem::childAt(qreal x, qreal y) const
 void QDeclarativeItemPrivate::focusChanged(bool flag)
 {
     Q_Q(QDeclarativeItem);
-    if (!(flags & QGraphicsItem::ItemIsFocusScope) && parent)
-        emit q->activeFocusChanged(flag);   //see also QDeclarativeItemPrivate::subFocusItemChange()
-    emit q->focusChanged(flag);
+
+    if (hadActiveFocus != flag) {
+        hadActiveFocus = flag;
+        emit q->activeFocusChanged(flag);
+    }
+
+    QDeclarativeItem *focusItem = q;
+    for (QDeclarativeItem *p = q->parentItem(); p; p = p->parentItem()) {
+        if (p->flags() & QGraphicsItem::ItemIsFocusScope) {
+            if (!flag && QGraphicsItemPrivate::get(p)->focusScopeItem != focusItem)
+                break;
+            if (p->d_func()->hadActiveFocus != flag) {
+                p->d_func()->hadActiveFocus = flag;
+                emit p->activeFocusChanged(flag);
+            }
+            focusItem = p;
+        }
+    }
+
+    // For all but the top most focus scope/item this will be called for us by QGraphicsItem.
+    focusItem->d_func()->focusScopeItemChange(flag);
 }
 
 QDeclarativeListProperty<QObject> QDeclarativeItemPrivate::resources()
diff --git a/src/declarative/graphicsitems/qdeclarativeitem_p.h b/src/declarative/graphicsitems/qdeclarativeitem_p.h
index 8ef918874b..2026230783 100644
--- a/src/declarative/graphicsitems/qdeclarativeitem_p.h
+++ b/src/declarative/graphicsitems/qdeclarativeitem_p.h
@@ -128,8 +128,8 @@ public:
       componentComplete(true), keepMouse(false),
       smooth(false), transformOriginDirty(true), doneEventPreHandler(false),
       inheritedLayoutMirror(false), effectiveLayoutMirror(false), isMirrorImplicit(true),
-      inheritMirrorFromParent(false), inheritMirrorFromItem(false), keyHandler(0),
-      mWidth(0), mHeight(0), mImplicitWidth(0), mImplicitHeight(0), attachedLayoutDirection(0), hadSubFocusItem(false)
+      inheritMirrorFromParent(false), inheritMirrorFromItem(false), hadFocus(false), hadActiveFocus(false), keyHandler(0),
+      mWidth(0), mHeight(0), mImplicitWidth(0), mImplicitHeight(0), attachedLayoutDirection(0)
     {
         QGraphicsItemPrivate::acceptedMouseButtons = 0;
         isDeclarativeItem = 1;
@@ -289,6 +289,8 @@ public:
     bool isMirrorImplicit:1;
     bool inheritMirrorFromParent:1;
     bool inheritMirrorFromItem:1;
+    bool hadFocus:1;
+    bool hadActiveFocus:1;
 
     QDeclarativeItemKeyFilter *keyHandler;
 
@@ -299,7 +301,6 @@ public:
 
     QDeclarativeLayoutMirroringAttached* attachedLayoutDirection;
 
-    bool hadSubFocusItem;
 
     QPointF computeTransformOrigin() const;
 
@@ -312,22 +313,14 @@ public:
     }
 
     // Reimplemented from QGraphicsItemPrivate
-    virtual void subFocusItemChange()
-    {
-        bool hasSubFocusItem = subFocusItem != 0;
-        if (((flags & QGraphicsItem::ItemIsFocusScope) || !parent) && hasSubFocusItem != hadSubFocusItem)
-            emit q_func()->activeFocusChanged(hasSubFocusItem);
-        //see also QDeclarativeItemPrivate::focusChanged
-        hadSubFocusItem = hasSubFocusItem;
-    }
-
-    // Reimplemented from QGraphicsItemPrivate
     virtual void focusScopeItemChange(bool isSubFocusItem)
     {
-        emit q_func()->focusChanged(isSubFocusItem);
+        if (hadFocus != isSubFocusItem) {
+            hadFocus = isSubFocusItem;
+            emit q_func()->focusChanged(isSubFocusItem);
+        }
     }
 
-
     // Reimplemented from QGraphicsItemPrivate
     virtual void siblingOrderChange()
     {