QQuickMultiPointHandler::moveTarget(): work with interceptors

As with WheelHandler, DragHandler also needs to allow the target movements
to be constrained with interceptors like BoundaryRule.

Also do a null pointer check in moveTarget(): we haven't needed it before, but
we are becoming more open to subclassing, so need to prevent user foot-shooting.

Change-Id: I6b39b6dd2ca8245c56ecb3812e6de9624b36fa50
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

1 files changed, 27 insertions, 2 deletions

diff --git a/src/quick/handlers/qquickmultipointhandler.cpp b/src/quick/handlers/qquickmultipointhandler.cpp
index ceadbf3ada..5c10ecce75 100644
--- a/src/quick/handlers/qquickmultipointhandler.cpp
+++ b/src/quick/handlers/qquickmultipointhandler.cpp
@@ -384,8 +384,13 @@ bool QQuickMultiPointHandler::grabPoints(QVector<QQuickEventPoint *> points)
 void QQuickMultiPointHandler::moveTarget(QPointF pos)
 {
     Q_D(QQuickMultiPointHandler);
-    target()->setPosition(pos);
-    d->centroid.m_position = target()->mapFromScene(d->centroid.m_scenePosition);
+    if (QQuickItem *t = target()) {
+        d->xMetaProperty().write(t, pos.x());
+        d->yMetaProperty().write(t, pos.y());
+        d->centroid.m_position = t->mapFromScene(d->centroid.m_scenePosition);
+    } else {
+        qWarning() << "moveTarget: target is null";
+    }
 }
 
 QQuickMultiPointHandlerPrivate::QQuickMultiPointHandlerPrivate(int minPointCount, int maxPointCount)
@@ -395,4 +400,24 @@ QQuickMultiPointHandlerPrivate::QQuickMultiPointHandlerPrivate(int minPointCount
 {
 }
 
+QMetaProperty &QQuickMultiPointHandlerPrivate::xMetaProperty() const
+{
+    Q_Q(const QQuickMultiPointHandler);
+    if (!xProperty.isValid() && q->target()) {
+        const QMetaObject *targetMeta = q->target()->metaObject();
+        xProperty = targetMeta->property(targetMeta->indexOfProperty("x"));
+    }
+    return xProperty;
+}
+
+QMetaProperty &QQuickMultiPointHandlerPrivate::yMetaProperty() const
+{
+    Q_Q(const QQuickMultiPointHandler);
+    if (!yProperty.isValid() && q->target()) {
+        const QMetaObject *targetMeta = q->target()->metaObject();
+        yProperty = targetMeta->property(targetMeta->indexOfProperty("y"));
+    }
+    return yProperty;
+}
+
 QT_END_NAMESPACE