RecyclerView内部的可滚动MapView:dispatchTouchEvent与onTouchEvent [英] Scrollable MapView inside of a RecyclerView: dispatchTouchEvent vs onTouchEvent

问题描述

我正在尝试在RecyclerView中使用滚动的MapView，因此我在TouchEvent之前和之后设置了requestDisallowInterceptTouchEvent().

I'm trying to have a scrolling MapView inside of a RecyclerView, therefore I'm setting requestDisallowInterceptTouchEvent() before and after the TouchEvent.

奇怪的是:如果我在dispatchTouchEvent()方法中进行了设置，它确实可以工作，但是如果我在onTouchEvent()方法中进行了同样的操作，则它就无法工作.

The odd thing is: this does work if I set it in the dispatchTouchEvent() method, but it doesn't work if I do the same in the onTouchEvent() method.

有人可以解释为什么我不能在onTouchEvent()中进行设置吗?

Can somebody explain why I cannot set this in onTouchEvent()?

工作:

public class WorkingScrollableListItemMapView extends MapView {

    // constructors

    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        switch (ev.getAction()) {
            case MotionEvent.ACTION_DOWN:
                // Stop parents from handling the touch
                this.getParent().requestDisallowInterceptTouchEvent(true);
            break;
            case MotionEvent.ACTION_UP:
                // Allow parents from handling the touch
                this.getParent().requestDisallowInterceptTouchEvent(false);
                break;
        }
        return super.dispatchTouchEvent(ev);
    }
}

不起作用:

public class NotWorkingScrollableListItemMapView extends MapView {

    // constructors

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        switch (ev.getAction()) {
            case MotionEvent.ACTION_UP:
                // Allow parents from handling the touch
                this.getParent().requestDisallowInterceptTouchEvent(false);
                break;
            case MotionEvent.ACTION_DOWN:
                // Stop parents from handling the touch
                this.getParent().requestDisallowInterceptTouchEvent(true);
                break;
        }
        return super.onTouchEvent(ev);
    }
}

推荐答案

用于处理事件的调用顺序如下: onInterceptTouchEvent，onDispatchTouchEvent，dispatchTouchEvent，onTouchEvent. 对我而言，这表明onTouchEvent是处理事件的最后一步.要在何处&谁在最后一步处理事件.如果您查看处理事件的早期方法，源代码怎么说?

Call sequence for handling an event are somewhat in this order: onInterceptTouchEvent, onDispatchTouchEvent, dispatchTouchEvent, onTouchEvent. That, to me, indicates that the onTouchEvent is the very last step in processing an event. It would be too late to manipulate where & whom handles the event at the very last step. What does the source code say if you look at the earlier methods for handling the event?

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