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说说GestureDetector.OnGestureListener onScroll函数
public abstract boolean onScroll (MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)
Since: API Level 1
Notified when a scroll occurs with the initial on down MotionEvent and the current move MotionEvent. The distance in x and y is also supplied for convenience.
Parameters
| e1 | The first down motion event that started the scrolling. |
|---|---|
| e2 | The move motion event that triggered the current onScroll. |
| distanceX | The distance along the X axis that has been scrolled since the last call to onScroll. This is NOT the distance between e1 and e2. |
| distanceY | The distance along the Y axis that has been scrolled since the last call to onScroll. This is NOT the distance between e1 and e2. |
Returns
- true if the event is consumed, else false
e1 初次触控地图的event1 down事件
e2 每次触发onScroll函数得到的的event2 最后一次move事件
distance是上一次的event2 减去 当前event2得到的结果 //注意到顺序
lastEvent2 - event2 = distance
验证：
[java] view plain copy
- if (lastE2 != null){
- Log.i(TAG, "distanceX:" + distanceX + " = " + (lastE2.getX()-e2.getX()));
- Log.i(TAG, "distanceY:" + distanceY + " = " + (lastE2.getY()-e2.getY()));
- }
- lastE2 = MotionEvent.obtain(e2);
说说GestureDetector.OnGestureListener onScroll函数
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