android 弹性效果
重写自己的view，覆盖父类的overScrollBy方法。
代码：

import android.content.Context;import android.util.AttributeSet;import android.util.DisplayMetrics;import android.widget.ScrollView;/** * ClassName:MtScrollView * Function: TODO ADD FUNCTION . * * VERSION       DATE            AUTHOR       CHANGE/COMMENT * ──────────────────────────────────———————————————————————— * （产品版本号）             2012-4-23          duweibin         create */public class MtScrollView extends ScrollView {private static final int MAX_Y_OVERSCROLL_DISTANCE = 200;         private Context mContext;     private int mMaxYOverscrollDistance;           public MtScrollView(Context context){         super(context);         mContext = context;         initBounceListView();     }           public MtScrollView(Context context, AttributeSet attrs){         super(context, attrs);         mContext = context;         initBounceListView();    }           public MtScrollView(Context context, AttributeSet attrs, int defStyle){         super(context, attrs, defStyle);         mContext = context;         initBounceListView();     }           private void initBounceListView(){         final DisplayMetrics metrics = mContext.getResources().getDisplayMetrics();             final float density = metrics.density;                   mMaxYOverscrollDistance = (int) (density * MAX_Y_OVERSCROLL_DISTANCE);     }     @Override    protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY, int scrollRangeX, int scrollRangeY, int maxOverScrollX, int maxOverScrollY, boolean isTouchEvent){          //这块是关键性代码        return super.overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX, scrollRangeY, maxOverScrollX, mMaxYOverscrollDistance, isTouchEvent);       }}