Don't assume that target is the parent item

To summarize: A pointer handler always gets its pointer events from its
parent item. It applies its effect (drag, pinch, ...) on the item
referenced to by the target property. By default, target refers to the
parent, but that is not always the case. In addition to this we also
have to handle the case when the target is null

Change-Id: If62108abf0aeb713906bf88472ad9a32a74efff6
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

1 files changed, 25 insertions, 17 deletions

diff --git a/src/quick/handlers/qquickpointerhandler.cpp b/src/quick/handlers/qquickpointerhandler.cpp
index 6225d2a24a..d51835a24b 100644
--- a/src/quick/handlers/qquickpointerhandler.cpp
+++ b/src/quick/handlers/qquickpointerhandler.cpp
@@ -60,9 +60,19 @@ QQuickPointerHandler::QQuickPointerHandler(QObject *parent)
   , m_target(nullptr)
   , m_enabled(true)
   , m_active(false)
+  , m_targetExplicitlySet(false)
 {
 }
 
+QQuickPointerHandler::~QQuickPointerHandler()
+{
+    QQuickItem *parItem = parentItem();
+    if (parItem) {
+        QQuickItemPrivate *p = QQuickItemPrivate::get(parItem);
+        p->extra.value().pointerHandlers.removeOne(this);
+    }
+}
+
 void QQuickPointerHandler::setGrab(QQuickEventPoint *point, bool grab)
 {
     if (grab) {
@@ -81,14 +91,16 @@ void QQuickPointerHandler::setGrab(QQuickEventPoint *point, bool grab)
 
 QPointF QQuickPointerHandler::eventPos(const QQuickEventPoint *point) const
 {
-    return (m_target ? m_target->mapFromScene(point->scenePos()) : point->scenePos());
+    return (target() ? target()->mapFromScene(point->scenePos()) : point->scenePos());
 }
 
-bool QQuickPointerHandler::targetContains(const QQuickEventPoint *point) const
+bool QQuickPointerHandler::parentContains(const QQuickEventPoint *point) const
 {
-    if (!m_target || !point)
-        return false;
-    return m_target->contains(m_target->mapFromScene(point->scenePos()));
+    if (point) {
+        if (QQuickItem *par = parentItem())
+            return par->contains(par->mapFromScene(point->scenePos()));
+    }
+    return false;
 }
 
 /*!
@@ -111,25 +123,21 @@ void QQuickPointerHandler::setEnabled(bool enabled)
 
 void QQuickPointerHandler::setTarget(QQuickItem *target)
 {
+    m_targetExplicitlySet = true;
     if (m_target == target)
         return;
 
-    if (m_target) {
-        QQuickItemPrivate *p = QQuickItemPrivate::get(m_target);
-        p->extra.value().pointerHandlers.removeOne(this);
-    }
-
     m_target = target;
-    if (m_target) {
-        QQuickItemPrivate *p = QQuickItemPrivate::get(m_target);
-        p->extra.value().pointerHandlers.append(this);
-        // Accept all buttons, and leave filtering to pointerEvent() and/or user JS,
-        // because there can be multiple handlers...
-        m_target->setAcceptedMouseButtons(Qt::AllButtons);
-    }
     emit targetChanged();
 }
 
+QQuickItem *QQuickPointerHandler::target() const
+{
+    if (!m_targetExplicitlySet)
+        return parentItem();
+    return m_target;
+}
+
 void QQuickPointerHandler::handlePointerEvent(QQuickPointerEvent *event)
 {
     const bool wants = wantsPointerEvent(event);