How to get initial X, Y values (of first touch ACTION_DOWN) in OnTouchListener

Question

I need initial x and y values (the point that moving begun with first touch ACTION_DOWN) in order to calculate deltaX and deltaY as follows;

private float mInitialTouchX = Float.NaN;          // # First touch temp var defined globally
...
someView.setOnTouchListener(new OnTouchListener() {         
    @Override public boolean onTouch(View v, MotionEvent event) 
    {
        switch (event.getAction()) 
        {
            case MotionEvent.ACTION_MOVE:
                MoveViewHorizontally(v, event.getX(), mInitialTouchX);                      
                break;
            case MotionEvent.ACTION_DOWN:
                mInitialTouchX = event.getX();    // # Set initial touch point
                break;
            case MotionEvent.ACTION_UP:                     
                mInitialTouchX = Float.NaN;       // # Reset initial touch point
                break;
            default: break;
        }
        return false;
    }           
});

private void MoveViewHorizontally(View v, float x, float initialTouchX)
{
    int deltaX = (int)(x - initialTouchX);      

    ViewGroup.MarginLayoutParams layoutParams = (ViewGroup.MarginLayoutParams) v.getLayoutParams();     

    layoutParams.leftMargin += deltaX;
    v.setLayoutParams(layoutParams);
}

Is there a way that i can get initial touch values from event or somehow - somewhere else, avoiding usage of global variable mInitialTouchX ?

Answer 1

Nope, there is no better way. You're doing it the right way. In fact, if you take a look at the code for GestureDetector, you will see that they are doing it more or less the same way.