Android: Treat ACTION_CANCEL as TouchCancelEvent

Change 64d62c53c1e92a1cc07449a0ea3c71501592c1e7 started treating an
ACTION_CANCEL as a TouchPointReleased. This leads to unintentional
presses, if e.g. an edge swipe for the android back gesture starts on a
MouseArea.

When Android takes possession of the motion, an ACTION_CANCEL is
delivered, which needs to be handled as such. It should not be treated
as a normal up event that triggers a press. Otherwise, we get the
above-mentioned issue, where an unintentional action is performed.
So let's use QWindowSystemInterface::handleTouchCancelEvent to treat it
as a canceled touch in Qt.

Task-number: QTBUG-72110
Change-Id: I68650a180130501568e5a1e9a7f20ea469461e97
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
(cherry picked from commit d6da61f3b9e7e57e85d1e16f2756a8e39e571f77)

2 files changed, 40 insertions, 9 deletions

diff --git a/src/android/jar/src/org/qtproject/qt5/android/QtNative.java b/src/android/jar/src/org/qtproject/qt5/android/QtNative.java
index 6742a3781b..b077014b81 100644
--- a/src/android/jar/src/org/qtproject/qt5/android/QtNative.java
+++ b/src/android/jar/src/org/qtproject/qt5/android/QtNative.java
@@ -708,9 +708,11 @@ public class QtNative
             }
             return 1;
         }
-        if (action == MotionEvent.ACTION_DOWN || action == MotionEvent.ACTION_POINTER_DOWN && index == event.getActionIndex()) {
+        if (action == MotionEvent.ACTION_DOWN
+            || action == MotionEvent.ACTION_POINTER_DOWN && index == event.getActionIndex()) {
             return 0;
-        } else if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_POINTER_UP && index == event.getActionIndex()) {
+        } else if (action == MotionEvent.ACTION_UP
+            || action == MotionEvent.ACTION_POINTER_UP && index == event.getActionIndex()) {
             return 3;
         }
         return 2;
@@ -762,6 +764,10 @@ public class QtNative
                     touchEnd(id, 2);
                     break;
 
+                case MotionEvent.ACTION_CANCEL:
+                    touchCancel(id);
+                    break;
+
                 default:
                     touchEnd(id, 1);
             }
@@ -1365,6 +1371,7 @@ public class QtNative
     public static native void touchBegin(int winId);
     public static native void touchAdd(int winId, int pointerId, int action, boolean primary, int x, int y, float major, float minor, float rotation, float pressure);
     public static native void touchEnd(int winId, int action);
+    public static native void touchCancel(int winId);
     public static native void longPress(int winId, int x, int y);
     // pointer methods
 
diff --git a/src/plugins/platforms/android/androidjniinput.cpp b/src/plugins/platforms/android/androidjniinput.cpp
index 8ec77e7c97..726caa5015 100644
--- a/src/plugins/platforms/android/androidjniinput.cpp
+++ b/src/plugins/platforms/android/androidjniinput.cpp
@@ -263,18 +263,14 @@ namespace QtAndroidInput
         }
     }
 
-    static void touchEnd(JNIEnv */*env*/, jobject /*thiz*/, jint /*winId*/, jint /*action*/)
+    static QTouchDevice *getTouchDevice()
     {
-        if (m_touchPoints.isEmpty())
-            return;
-
-        QMutexLocker lock(QtAndroid::platformInterfaceMutex());
         QAndroidPlatformIntegration *platformIntegration = QtAndroid::androidPlatformIntegration();
         if (!platformIntegration)
-            return;
+            return nullptr;
 
         QTouchDevice *touchDevice = platformIntegration->touchDevice();
-        if (touchDevice == 0) {
+        if (!touchDevice) {
             touchDevice = new QTouchDevice;
             touchDevice->setType(QTouchDevice::TouchScreen);
             touchDevice->setCapabilities(QTouchDevice::Position
@@ -285,10 +281,37 @@ namespace QtAndroidInput
             platformIntegration->setTouchDevice(touchDevice);
         }
 
+        return touchDevice;
+    }
+
+    static void touchEnd(JNIEnv * /*env*/, jobject /*thiz*/, jint /*winId*/, jint /*action*/)
+    {
+        if (m_touchPoints.isEmpty())
+            return;
+
+        QMutexLocker lock(QtAndroid::platformInterfaceMutex());
+        QTouchDevice *touchDevice = getTouchDevice();
+        if (!touchDevice)
+            return;
+
         QWindow *window = QtAndroid::topLevelWindowAt(m_touchPoints.at(0).area.center().toPoint());
         QWindowSystemInterface::handleTouchEvent(window, touchDevice, m_touchPoints);
     }
 
+    static void touchCancel(JNIEnv * /*env*/, jobject /*thiz*/, jint /*winId*/)
+    {
+        if (m_touchPoints.isEmpty())
+            return;
+
+        QMutexLocker lock(QtAndroid::platformInterfaceMutex());
+        QTouchDevice *touchDevice = getTouchDevice();
+        if (!touchDevice)
+            return;
+
+        QWindow *window = QtAndroid::topLevelWindowAt(m_touchPoints.at(0).area.center().toPoint());
+        QWindowSystemInterface::handleTouchCancelEvent(window, touchDevice);
+    }
+
     static bool isTabletEventSupported(JNIEnv */*env*/, jobject /*thiz*/)
     {
 #if QT_CONFIG(tabletevent)
@@ -840,6 +863,7 @@ namespace QtAndroidInput
         {"touchBegin","(I)V",(void*)touchBegin},
         {"touchAdd","(IIIZIIFFFF)V",(void*)touchAdd},
         {"touchEnd","(II)V",(void*)touchEnd},
+        {"touchCancel", "(I)V", (void *)touchCancel},
         {"mouseDown", "(III)V", (void *)mouseDown},
         {"mouseUp", "(III)V", (void *)mouseUp},
         {"mouseMove", "(III)V", (void *)mouseMove},