如何在应用程序外部的屏幕上使用检测手指轻扫

Question

In my app I want to use GestureEvents to detect swipe done by the user like this:

GestureDetector gd=new GestureDetector(this,this); //code is implemented in MainActivity of my app

@Override
public boolean onTouchEvent(MotionEvent event){
    return gd.onTouchEvent(event);
}

@Override
public boolean onDown(MotionEvent e) {
    return false;
}

@Override
public void onShowPress(MotionEvent e) {

}

@Override
public boolean onSingleTapUp(MotionEvent e) {
    return false;
}

@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
    return false;
}

@Override
public void onLongPress(MotionEvent e) {

}

@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {

    float sensitivity =50;
    if(e1.getX()-e2.getX()>sensitivity){
        Toast.makeText(MainActivity.this,"left swipe",Toast.LENGTH_SHORT).show();
        return true;
    }
    else if(e2.getX()-e1.getX()>sensitivity){
        Toast.makeText(MainActivity.this,"right swipe",Toast.LENGTH_SHORT).show();
        return true;
    }
   else{
        return true;
    }
}

From the above code I can get to know weather user has swiped left or right on screen.But it detects until my activity is in foreground when my app goes background it doesn't detects any motions done on the screen.I want it to work outside of my app too even if the app is destroyed.Is it possible how can I do that please help me.

Answer 1

Use below code for swipe detection, may be it is helpful to you, in my project working perfectly, so you can try this..

public class OnSwipeTouchListener implements OnTouchListener {

private final GestureDetector gestureDetector;
int SWIPE_THRESHOLD = 200;
int SWIPE_VELOCITY_THRESHOLD = 200;

public OnSwipeTouchListener(Context context) {
    gestureDetector = new GestureDetector(context, new CustomGestureListenerClass());
}

@Override
public boolean onTouch(View v, MotionEvent event) {
    return gestureDetector.onTouchEvent(event);
}

private final class CustomGestureListenerClass extends SimpleOnGestureListener {


    @Override
    public boolean onDown(MotionEvent e) {
        return false;
    }

    @Override
    public boolean onSingleTapUp(MotionEvent e) {
        singleClicked(e);
        return super.onSingleTapUp(e);
    }

    @Override
    public boolean onScroll(MotionEvent startMotionEvent, MotionEvent endMotionEvent, float distanceX, float distanceY) {
        return super.onScroll(startMotionEvent, endMotionEvent, distanceX, distanceY);
    }


    @Override
    public boolean onFling(MotionEvent startMotionEvent, MotionEvent endMotionEvent, float velocityX, float velocityY) {

        boolean result = false;
        try {
            float diffY = endMotionEvent.getY() - startMotionEvent.getY();
            float diffX = endMotionEvent.getX() - startMotionEvent.getX();
            if (Math.abs(diffX) > Math.abs(diffY)) {
                if (Math.abs(diffX) > SWIPE_THRESHOLD && Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
                    if (diffX > 0) {
                        onSwipeRight();
                    } else {
                        onSwipeLeft();
                    }
                }
                result = true;
            }
            result = true;
        } catch (Exception exception) {
            exception.printStackTrace();
        }
        return result;
    }
}

public void onSwipeRight() {
    // if you want done some portion before call this method then write here
}

public void onSwipeLeft() {
    // if you want done some portion before call this method then write here
}

public void singleClicked(MotionEvent e) {
}
}

and configure on activity using below code

getWindow().getDecorView().setOnTouchListener(new OnSwipeTouchListener(this) {
});