android - ScaleGestureDetector.onTouchEvent 总是返回 'true'

Question

我认为“ScaleGestureDetector”实例的“onTouchEvent()”方法应该返回“true”只有当它真正处理触摸事件时，即。 e.如果它检测到多点触控缩放手势(用两根手指)。否则我认为它应该返回“false”以便让其他处理程序处理事件，例如。 G。长按触发上下文菜单。

我观察到一些不同的事情:在我的情况下，scaleGestureDetector.onTouchEvent() 总是返回“true”。 MyView 类的以下代码 fragment :

public boolean onTouchEvent(MotionEvent event) {
  boolean retval = scaleGestureDetector.onTouchEvent(event);
   Log.v("MyView.onTouchEvent()", "Action: " + event.getAction() +
         "; PointerCount: " + event.getPointerCount() +
         "; scaleGestureDetector.onTouchEvent() RetVal: " + retval);
   return(retval);
}

在我用一根手指触摸 View 大约 1 秒后产生以下日志输出，然后用两根手指执行缩放手势:

01-01 19:09:54.484: VERBOSE/MyView.onTouchEvent()(5930): Action: 0; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:09:54.510: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:09:54.541: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:09:54.580: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:09:54.820: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:09:54.910: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:09:55.050: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:09:55.350: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:09:55.400: VERBOSE/MyView.onTouchEvent()(5930): Action: 1; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:09:57.160: INFO/BatteryStatsImpl(96): notePhoneSignalStrengthLocked: 4->3
01-01 19:10:00.060: ERROR/ClockWidget(215): weatherClock onReceive~ mUseAnimation:false
01-01 19:10:00.060: ERROR/ClockWidget(215): handleUiMessage~ in pause. msg:36867
01-01 19:10:00.070: ERROR/ClockWidget(215): weatherClock onReceive~ mUseAnimation:false
01-01 19:10:00.090: INFO/PI.Alarms(699): Update Alarms start
01-01 19:10:00.090: INFO/PI.Alarms(699): Task Notifications: Already displaying the same alarms, no update
01-01 19:10:00.100: INFO/PI.Alarms(699): Event Notifications: Already displaying the same alarms, no update
01-01 19:10:00.830: VERBOSE/MyView.onTouchEvent()(5930): Action: 0; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:00.840: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:00.870: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:00.900: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:00.922: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:00.931: VERBOSE/MyView.onTouchEvent()(5930): Action: 261; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:00.950: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.002: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.030: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.060: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.090: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.120: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.140: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.172: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.200: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.230: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.252: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.280: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.310: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.342: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.370: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.390: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.424: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.450: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.480: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.510: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.530: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.580: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.690: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.780: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.815: VERBOSE/MyView.onTouchEvent()(5930): Action: 2; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.830: VERBOSE/MyView.onTouchEvent()(5930): Action: 262; PointerCount: 2; scaleGestureDetector.onTouchEvent() RetVal: true
01-01 19:10:01.840: VERBOSE/MyView.onTouchEvent()(5930): Action: 1; PointerCount: 1; scaleGestureDetector.onTouchEvent() RetVal: true

正如我所说:返回值总是“真”!这是 ScaleGestureDetector.onTouchEvent() 的错误吗？我该怎么做才能让其他处理程序处理所有非比例手势事件(例如用一根手指长按)？请帮忙!

Nemax

Answer 1

不知道这是一个错误还是故意的，但这绝对是源所做的(ScaleGestureDetector.java:156):

public boolean onTouchEvent(MotionEvent event) {
   final int action = event.getAction();
   boolean handled = true;

   /* ... bunch of code that never updates 'handled' */

   return handled;
}

我解决这个问题的方法是先检查我可能想要处理的所有其他类型的触摸事件，然后调用手势检测器，例如

    if (mLongPressGestureDetector != null && mLongPressGestureDetector.onTouchEvent(event))
        return true;
    else if (mIsInMoveMode && mScaleGestureDetector != null) {
        // Check for a move
        if (action == MotionEvent.ACTION_MOVE && !mScaleGestureDetector.isInProgress()) {
            handleMove(event);
            return true;
        }

        // Now a scale
        mScaleGestureDetector.onTouchEvent(event);
        return true;
    }