How to implement a two-finger double-click in Android?

Question

I know how to detect a double-click and a two-finger touch event, but how can I combine these to react so somebody needs to double click with two fingers?

By default

Answer 1

This is a double-click listener I created to detect a two-finger double click.

Variables used:

private GestureDetector gesture;
private View.OnTouchListener gestureListener;
boolean click1 = false;
boolean click2 = false;
long first = 0;
long second = 0;

In the activity's onCreate() to register the touch events:

gesture = new GestureDetector(getApplicationContext(), new SimpleOnGestureListener(){
    public boolean onDown(MotionEvent event) {
        return true;
    }
});
gestureListener = new View.OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        return gesture.onTouchEvent(event);
    }
};

Outside of onCreate() inside the activity:

@Override
public boolean onTouchEvent(MotionEvent event) {   
    try {
        int action = event.getAction() & MotionEvent.ACTION_MASK;
        //capture the event when the user lifts their fingers, not on the down press
        //to make sure they're not long pressing
        if (action == MotionEvent.ACTION_POINTER_UP) {
            //timer to get difference between clicks
            Calendar now = Calendar.getInstance();

            //detect number of fingers, change to 1 for a single-finger double-click, 3 for a triple-finger double-click, etc.
            if (event.getPointerCount() == 2) {
                if (!click1) {
                    //if this is the first click, then there hasn't been a second
                    //click yet, also record the time
                    click1 = true;
                    click2 = false;
                    first = now.getTimeInMillis(); 
                } else if (click1) {
                    //if this is the second click, record its time 
                    click2 = true;
                    second = now.getTimeInMillis();

                    //if the difference between the 2 clicks is less than 500 ms (1/2 second)
                    //Math.abs() is used because you need to be able to detect any sequence of clicks, rather than just in pairs of two
                    //(e.g. click1 could be registered as a second click if the difference between click1 and click2 > 500 but
                    //click2 and the next click1 is < 500)
                    if (Math.abs(second-first) < 500) {

                        //do something!!!!!!

                    } else if (Math.abs(second-first) >= 500) {
                        //reset to handle more clicks
                        click1 = false;
                        click2 = false;
                    }
                }
            }
        }
    } catch (Exception e){

    }
    return true;
}