說說GestureDetector.OnGestureListener onScroll函數

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 <code>e1</code> and <code>e2</code>.

distanceY

The distance along the Y axis that has been scrolled since the last call to onScroll. This is NOT the distance between <code>e1</code> and <code>e2</code>.

true if the event is consumed, else false

e1 初次觸控地圖的event1  down事件

e2 每次觸發onScroll函數得到的的event2   最後一次move事件

distance是上一次的event2 減去 目前event2得到的結果 //注意到順序 

lastEvent2 - event2 = distance

驗證：

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);  

    本文轉自 一點點征服   部落格園部落格，原文連結：http://www.cnblogs.com/ldq2016/p/7000315.html，如需轉載請自行聯系原作者