Android : How to implement longpress manually in touch event?

Question

Short version: I want a way to start a time-based counter on an onTouchEvent, and test to see if a certain amount of time has passed before responding, as a manual LongTouch det

Answer 1

I'm not sure from you question, but it seems that you're trying to implement a catch long click event in your onTouchListener except you need to perform some kind of logic before the ACTION_UP event happens? If so, that's the same exact problem I was having. I also tried using System.nanoTime() but I found a less tricky method. You CAN use a timer, you just have to schedule it on the first ACTION_DOWN event and cancel it when anything adverse happens (like an ACTION_UP which means it's wasn't a long press but just a click, or an ACTION_MOVE with a displacement over a certain threshold). Something like the following:

layout.seyOnTouchListener(new OnTouchListener(){
    private Timer longpressTimer; //won't depend on a motion event to fire
    private final int longpressTimeDownBegin = 500; //0.5 s
    private Point previousPoint;

    switch(event.getAction()){

    case MotionEvent.ACTION_DOWN:{
        longPressTimer = new Timer();
        longpressTimer.schedule(new TimerTask(){
            //whatever happens on a longpress
        }, longpressTimeDownBegin);
        return true; //the parent was also handling long clicks
    }
    case MotionEvent.ACTION_MOVE:{
        Point currentPoint = new Point((int)event.getX(), (int)event.getY());

        if(previousPoint == null){
            previousPoint = currentPoint;
        }
        int dx = Math.abs(currentPoint.x - previousPoint.x);
        int dy = Math.abs(currentPoint.y - previousPoint.y);
        int s = (int) Math.sqrt(dx*dx + dy*dy);
        boolean isActuallyMoving = s >= minDisToMove; //we're moving

        if(isActuallyMoving){ //only restart timer over if we're actually moving (threshold needed because everyone's finger shakes a little)
            cancelLongPress();
            return false; //didn't trigger long press (will be treated as scroll)
        }
        else{ //finger shaking a little, so continue to wait for possible long press
            return true; //still waiting for potential long press
        }
    }
    default:{
        cancelLongPress();
        return false;
    }
    }
}