private int mActivePointerId;
public boolean onTouchEvent(MotionEvent event) {
....
// Get the pointer ID
mActivePointerId = event.getPointerId(0);
// ... Many touch events later...
// Use the pointer ID to find the index of the active pointer
// and fetch its position
int pointerIndex = event.findPointerIndex(mActivePointerId);
// Get the pointer's current position
float x = event.getX(pointerIndex);
float y = event.getY(pointerIndex);
}