Android : How disable scroll movement when i move a bitmap?

I want move a bitmap in the screen, but i can do it only horizontally, because if I do it vertically, the scroll of the view start and the movement of the bitmap disappears. I have

public boolean onTouchEvent(MotionEvent event)

method where in case MOVE I change the X and Y of the bitmap. Then in onDraw() method I paint the bitmap. The scroll are in xml. Inside of it are a layout and inside a View.

I would like when I touch, in case DOWN, if I touch the bitmap, disable the scroll, but I is in other place no.

Can someone help me? Thanks and regards.