Android:无法识别OnTouch，MotionEvent.ACTION_MOVE? [英] Android: OnTouch, MotionEvent.ACTION_MOVE is not recognized?

问题描述

这是我的代码，我想检测手指何时落在屏幕上，因此当我触摸屏幕时会检测到ACTION_DOWN，但是当我用手指滑下屏幕时，无法识别ACTION_MOVE，也没有ACTION_UP 你知道为什么吗?

Here is my code, I want to detect when my finger goes down the screen so when I touch the screen I detect the ACTION_DOWN but when I go down the screen with my finger, ACTION_MOVE is not recognized, neither ACTION_UP Do you know why?

        float x=0;
protected void onCreate(Bundle savedInstanceState) {
        do things

        ImageView image2 = (ImageView) findViewById(R.id.imageView3);
        image2.setOnTouchListener(new OnTouchListener(){

        @Override
        public boolean onTouch(View arg0, MotionEvent arg1) {
            if (arg1.getAction()==MotionEvent.ACTION_DOWN) {

                x=arg1.getX();
            }
            else {
                if (arg1.getAction()==MotionEvent.ACTION_MOVE){
                    if (arg1.getX()>x) {
                    do things
                    }
                }
                else {
                    if (arg1.getAction()==MotionEvent.ACTION_UP){
                        do things
                    }
                }
            }
}

推荐答案

如果您的onTouch()方法返回false作为对初始ACTION_DOWN MotionEvent的响应，它将不会收到任何属于该事件的后续事件这个特定的手势.而是将那些触摸事件呈现给层次结构中的父级.

If your onTouch() method returns false in response to the initial ACTION_DOWN MotionEvent, it will not receive any of the subsequent events that belong to this particular gesture. Instead those touch events will be presented to the parent in the hierarchy.

换句话说，如果在手势开始时(ACTION_DOWN)从onTouch()返回false，则表示该方法不再希望看到任何手势，并且手势的事件应转到父View.

To phrase that another way, if you return false from onTouch() during the start of a gesture (the ACTION_DOWN), it signals that the method no longer wants to see any more of the gesture, and that the gesture's events should go to the parent View.

markproxy在下面的注释中指出，如果MotionEvent不是ACTION_DOWN，例如ACTION_MOVE，则返回false不会阻止 当前手势中的MotionEvent呈现给View.

As markproxy points out in the comments below, returning false when the MotionEvent is anything other than an ACTION_DOWN, such as an ACTION_MOVE for example, will not prevent subsequent MotionEvents in the current gesture being presented to the View.

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