按下操作起始于View外部时，如何检测该View是否被触摸？

当触摸起始于目标View外部时，目标View的OnTouchListener不会收到任何触摸事件——因为Android的触摸事件传递规则是：只有按下事件落在View的范围内，后续的滑动、抬起事件才会分发给该View。针对你在ScrollView中的场景，有以下几种可行方案：

方案1：给ScrollView添加全局触摸监听，在ACTION_UP时校验坐标 #

你之前认为全局坐标判断不可行，但只要正确获取目标View的屏幕坐标范围，就能准确判断抬起操作是否落在View3上，同时不会影响ScrollView的正常滑动：

scrollView.setOnTouchListener(new View.OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_UP) {
            // 获取View3的屏幕坐标
            int[] viewLocation = new int[2];
            view3.getLocationOnScreen(viewLocation);
            int viewLeft = viewLocation[0];
            int viewTop = viewLocation[1];
            int viewRight = viewLeft + view3.getWidth();
            int viewBottom = viewTop + view3.getHeight();

            // 获取触摸抬起时的屏幕坐标
            float touchX = event.getRawX();
            float touchY = event.getRawY();

            // 判断触摸点是否在View3范围内
            if (touchX >= viewLeft && touchX <= viewRight 
                && touchY >= viewTop && touchY <= viewBottom) {
                // 执行View3上释放的逻辑
                handleView3Release();
            }
        }
        return false; // 返回false，让ScrollView正常处理滑动事件
    }
});

方案2：自定义ScrollView，重写onTouchEvent #

如果想把触摸判断逻辑封装起来，可以自定义ScrollView，在内部处理抬起事件的坐标校验：

public class CustomScrollView extends ScrollView {
    private View mTargetView;
    private OnTargetReleaseListener mListener;

    public CustomScrollView(Context context) {
        super(context);
    }

    public CustomScrollView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    // 设置要检测的目标View和监听回调
    public void setTargetReleaseView(View targetView, OnTargetReleaseListener listener) {
        mTargetView = targetView;
        mListener = listener;
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        if (ev.getAction() == MotionEvent.ACTION_UP && mTargetView != null && mListener != null) {
            int[] location = new int[2];
            mTargetView.getLocationOnScreen(location);
            int left = location[0];
            int top = location[1];
            int right = left + mTargetView.getWidth();
            int bottom = top + mTargetView.getHeight();

            float touchX = ev.getRawX();
            float touchY = ev.getRawY();

            if (touchX >= left && touchX <= right && touchY >= top && touchY <= bottom) {
                mListener.onTargetReleased();
            }
        }
        return super.onTouchEvent(ev);
    }

    // 自定义回调接口
    public interface OnTargetReleaseListener {
        void onTargetReleased();
    }
}

使用时，在布局中替换为CustomScrollView，然后设置目标View和监听：

CustomScrollView customScrollView = findViewById(R.id.custom_scroll_view);
customScrollView.setTargetReleaseView(view3, new CustomScrollView.OnTargetReleaseListener() {
    @Override
    public void onTargetReleased() {
        handleView3Release();
    }
});

方案3：结合GestureDetector处理触摸手势 #

如果需要同时处理其他触摸手势，可以用GestureDetector辅助，在抬起时做坐标判断：

GestureDetector gestureDetector = new GestureDetector(this, new GestureDetector.SimpleOnGestureListener() {
    // 可以在这里处理其他手势，比如滑动、双击等
});

scrollView.setOnTouchListener(new View.OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        gestureDetector.onTouchEvent(event);
        if (event.getAction() == MotionEvent.ACTION_UP) {
            checkTouchInView3(event);
        }
        return false;
    }
});

// 提取坐标判断逻辑为单独方法
private void checkTouchInView3(MotionEvent event) {
    int[] location = new int[2];
    view3.getLocationOnScreen(location);
    int left = location[0];
    int top = location[1];
    int right = left + view3.getWidth();
    int bottom = top + view3.getHeight();

    float x = event.getRawX();
    float y = event.getRawY();

    if (x >= left && x <= right && y >= top && y <= bottom) {
        handleView3Release();
    }
}

关键说明 #

Android触摸事件的传递是按下事件决定后续事件的接收者：只有当ACTION_DOWN落在某个View范围内，该View才会收到后续的ACTION_MOVE和ACTION_UP。所以从View B按下后，所有触摸事件都会传递给View B或其上层容器，View3永远不会收到事件，必须从ScrollView（父容器）层面去拦截判断。

内容的提问来源于stack exchange，提问作者aWiseMan