SwipeDelegate: fix animations when releasing from a drag5.7

9812a9c changed the order in which the pressed and position
state is set. Before, when releasing after swiping, it would be:

set pressed to false => set position

After 9812a9c, it became:

set position => set pressed to false

The original order is necessary to ensure that animations can rely
on being enabled *before* position changes, as their enabled
expression typically looks something like this:

    enabled: !control.down

This patch duplicates the contents of
QQuickAbstractButton::mouseUngrabEvent() for now, with a TODO
comment to ensure that it's moved into a private helper that we can
call later on.

Task-number: QTBUG-57350
Change-Id: I31af7a665fb2d0e37548df31560ed7bbb0c3cadb
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>
Reviewed-by: J-P Nurmi <jpnurmi@qt.io>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/quicktemplates2/qquickswipedelegate.cpp b/src/quicktemplates2/qquickswipedelegate.cpp
index 0eac7fe1..f07b107e 100644
--- a/src/quicktemplates2/qquickswipedelegate.cpp
+++ b/src/quicktemplates2/qquickswipedelegate.cpp
@@ -698,6 +698,21 @@ bool QQuickSwipeDelegatePrivate::handleMouseReleaseEvent(QQuickItem *, QMouseEve
     const bool hadGrabbedMouse = q->keepMouseGrab();
     q->setKeepMouseGrab(false);
 
+    // Animations for the background and contentItem delegates are typically
+    // only enabled when !control.down, so that the animations aren't running
+    // when the user is swiping. To ensure that the animations are enabled
+    // *before* the positions of these delegates change (via the swipe.setPosition() calls below),
+    // we must cancel the press. QQuickAbstractButton::mouseUngrabEvent() does this
+    // for us, but by then it's too late.
+    if (hadGrabbedMouse) {
+        // TODO: this is copied from QQuickAbstractButton::mouseUngrabEvent().
+        // Eventually it should be moved into a private helper so that we don't have to duplicate it.
+        q->setPressed(false);
+        stopPressRepeat();
+        stopPressAndHold();
+        emit q->canceled();
+    }
+
     // The control can be exposed by either swiping past the halfway mark, or swiping fast enough.
     const qreal swipeVelocity = swipePrivate->velocityCalculator.velocity().x();
     if (swipePrivate->position > 0.5 ||