在自定义视图中放大布局后，输入事件异常

时间：2019-04-08 23:30:13

标签： android android-layout

我正在尝试创建一个CustomView，该CustomView扩展NestedScrollView并实现BottomSheetBehavior。我想允许自定义视图的用户传递XML属性，该XML属性指向要在NestedScrollView（底部）内部膨胀的布局。

在研究View生命周期时，我了解到在屏幕上显示视图后，我需要对传入的布局进行充气，因此，我像这样覆盖了dispatchDraw（我已经尝试了onDraw并获得了同样的成功）：

@Override
protected void dispatchDraw(Canvas canvas) {
    super.dispatchDraw(canvas);
    initPassedLayout();
}

它实际上可以在屏幕上正常显示，但是，一旦我触摸屏幕，我就会收到此异常（没有一个指向我的任何代码）：

2019-04-08 16:15:12.001 15810-15810/com.demo E/InputEventReceiver: Exception dispatching input event.
2019-04-08 16:15:12.002 15810-15810/com.demo E/MessageQueue-JNI: Exception in MessageQueue callback: handleReceiveCallback
2019-04-08 16:15:12.011 15810-15810/com.demo E/MessageQueue-JNI: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.support.v4.widget.ViewDragHelper.shouldInterceptTouchEvent(android.view.MotionEvent)' on a null object reference
        at android.support.design.widget.BottomSheetBehavior.onInterceptTouchEvent(BottomSheetBehavior.java:293)
        at android.support.design.widget.CoordinatorLayout.resetTouchBehaviors(CoordinatorLayout.java:394)
        at android.support.design.widget.CoordinatorLayout.onInterceptTouchEvent(CoordinatorLayout.java:509)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2573)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at com.android.internal.policy.DecorView.superDispatchTouchEvent(DecorView.java:440)
        at com.android.internal.policy.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1830)
        at android.app.Activity.dispatchTouchEvent(Activity.java:3400)
        at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:68)
        at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:68)
        at com.android.internal.policy.DecorView.dispatchTouchEvent(DecorView.java:398)
        at android.view.View.dispatchPointerEvent(View.java:12752)
        at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:5106)
        at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4909)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4479)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4445)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4585)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4453)
        at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4642)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4479)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4445)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4453)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:7092)
        at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:7061)
        at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:7022)
        at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:7195)
        at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:186)
        at android.os.MessageQueue.nativePollOnce(Native Method)
        at android.os.MessageQueue.next(MessageQueue.java:326)
        at android.os.Looper.loop(Looper.java:160)
        at android.app.ActivityThread.mai
2019-04-08 16:15:12.011 15810-15810/com.demo D/AndroidRuntime: Shutting down VM
2019-04-08 16:15:12.021 15810-15810/com.demo E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.demo, PID: 15810
    java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.support.v4.widget.ViewDragHelper.shouldInterceptTouchEvent(android.view.MotionEvent)' on a null object reference
        at android.support.design.widget.BottomSheetBehavior.onInterceptTouchEvent(BottomSheetBehavior.java:293)
        at android.support.design.widget.CoordinatorLayout.resetTouchBehaviors(CoordinatorLayout.java:394)
        at android.support.design.widget.CoordinatorLayout.onInterceptTouchEvent(CoordinatorLayout.java:509)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2573)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3030)
        at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2662)
        at com.android.internal.policy.DecorView.superDispatchTouchEvent(DecorView.java:440)
        at com.android.internal.policy.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1830)
        at android.app.Activity.dispatchTouchEvent(Activity.java:3400)
        at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:68)
        at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:68)
        at com.android.internal.policy.DecorView.dispatchTouchEvent(DecorView.java:398)
        at android.view.View.dispatchPointerEvent(View.java:12752)
        at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:5106)
        at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4909)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4479)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4445)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4585)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4453)
        at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4642)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4479)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4445)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4453)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4426)
        at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:7092)
        at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:7061)
        at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:7022)
        at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:7195)
        at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:186)
        at android.os.MessageQueue.nativePollOnce(Native Method)
2019-04-08 16:15:12.021 15810-15810/com.demo E/AndroidRuntime:     at android.os.MessageQueue.next(MessageQueue.java:326)
        at android.os.Looper.loop(Looper.java:160)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

任何建议将不胜感激。谢谢！

1 个答案:

答案 0 :(得分：0)

initPassedLayout（）被多次调用。记录了几件事之后，我知道了一遍又一遍地调用了dispatchDraw（）。覆盖并使用“ onAttachedToWindow（）”后，我的问题已解决。

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