AbhishekB AbhishekB - 3 months ago 53
Android Question

Ontouch event of OnTouchListener gets called twice in android

I am creating an appliction in which a line gets generated between two points given at runtime.

The problem that I see is that

onTouch()
is called twice for every click on my simulator. I know that two actions (
ACTION_DOWN
&
ACTION_UP
) are checked. But I want my app to call
onTouch()
just once. Please give me some ideas. This is the code that I used:

SurfaceView surfaceview = new SurfaceView(getContext());
SurfaceHolder h = surfaceview.getHolder();
int action = event.getActionMasked();
synchronized(h) {
if (action == MotionEvent.ACTION_DOWN && action!=MotionEvent.ACTION_CANCEL)// && flag==true)
{
Log.d("TouchView","ACTION_DOWN ");
Point pointer = new Point();
pointer.x = (int) event.getX();
pointer.y = (int) event.getY();
touchPoint.add(pointer);
view.invalidate();
Log.d("MotionEvent.ACTION_DOWN", "point: " + pointer);
action = MotionEvent.ACTION_CANCEL;
flag = false;
}
else if(action == MotionEvent.ACTION_UP && action!=MotionEvent.ACTION_CANCEL)// && flag==true)
{
Log.d("TouchView","ACTION_UP");
Point pointer = new Point();
pointer.x = (int) event.getX();
pointer.y = (int) event.getY();
touchPoint.add(pointer);
view.invalidate();
Log.d("MotionEvent.ACTION_UP", "point: " + pointer);
action = MotionEvent.ACTION_CANCEL;
flag = false;
}
else return false;
}

Answer

touchListener will be called for every MotionEvent.ACTION_DOWN, MotionEvent.ACTION_UP, and MotionEvent.ACTION_MOVE . so if you want to execute code only once , ie MotionEvent.ACTION_DOWN then inside

onTouch()
 if (event.getAction() == MotionEvent.ACTION_DOWN)
{
//your code 
}