Android OnTouch swipe up/down direction change -

i'm trying detect when swipe direction changed while user still swipes on screen.

i have (very basic) detecting swipe direction:

@override public boolean ontouch(view view, motionevent motionevent) {     int action = motionevent.getactionmasked();      switch (action) {         case motionevent.action_down: {             log.d(tag, "ontouch: down _y = " + motionevent.getrawy());             mlasttouchy = mprevtouchy = motionevent.getrawy();              break;         }         case motionevent.action_move: {             log.d(tag, "ontouch: move _y = " + motionevent.getrawy());              final float dy = motionevent.getrawy();             if (dy >= mlasttouchy) {                 /* move down */              } else {                 /* move */              }              break;         }         case motionevent.action_cancel:         case motionevent.action_outside:         case motionevent.action_up: {             log.d(tag, "ontouch: _y = " + motionevent.getrawy());              // snap page              break;         }     }      return true; } 

what need detect when user changed direction of swipe. example, code above fails detect edge cases:

1. start y = 100,
2. move down until 150,
3. move until 50,
4. move down again until 90

this detected swipe because initial y higher last y

should want detect direction change of swipe there simple way:

    private gesturedetector gesturedetector;      @override     protected void oncreate(bundle savedinstancestate) {         findviewbyid(r.id.myview).setontouchlistener(this);         gesturedetector = new gesturedetector(this, this);     } 

and implement ontouch , gesturelisteners this:

    @override     public boolean ontouch(view v, motionevent event) {         return gesturedetector.ontouchevent(event);     }      @override     public boolean onscroll(motionevent e1, motionevent e2, float distancex, float distancey) {         if (distancey > 0){             // going         } else {             // going down         }         return true;     }      @override     public boolean ondown(motionevent e) {         return true;     }     //the rest of methods must implement...