仿ios listview反弹效果

    前几天项目中要用到ios自带的反弹效果，就去看了下源码，其实我们android，反弹效果是有的，方法和实现都写好了。。。。。

    整个实现重点在overScrollBy这个方法上，当你滚动listview时会触发此事件，它会根据表头或表尾的坐标，及你所给的maxOverScrollY最大滚动纵坐标值来计算listview的表头或表尾的坐标。   

    默认的ListView的overScrollBy方法中maxOverScrollY=0；所以你只能看到在表头或表尾有一条带颜色的线闪灯，据说，这是为了避免IOS的专利....

    下面来看实现方式：

    MainActivity.java：

public class MainActivity extends Activity<span></span> {

 

     private BaseListView listview;

 

     @Override

     protected void onCreate(Bundle savedInstanceState)

     {

         super .onCreate(savedInstanceState);

         requestWindowFeature(Window.FEATURE_NO_TITLE);

         setContentView(R.layout.activity_main);

         listview = (BaseListView) findViewById(R.id.mylistview);

         ArrayAdapter<String> adapter = new ArrayAdapter<String>( this , android.R.layout.simple_expandable_list_item_1, new String[] { "A" , "A" , "A" , "A" , "A" , "A" , "A" , "A" , "A" });

         listview.setAdapter(adapter);

     }

 

}

?

     这个是重点 
     BaseListView.java 

?

public class BaseListView extends ListView

{

     private static final int MAX_Y_OVERSCROLL_DISTANCE = 200 ;

 

     private Context mContext;

     private int mMaxYOverscrollDistance;

 

     public BaseListView(Context context)

     {

         super (context);

         mContext = context;

         initBounceListView();

     }

 

     public BaseListView(Context context, AttributeSet attrs)

     {

         super (context, attrs);

         mContext = context;

         initBounceListView();

     }

 

     public BaseListView(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)

     {

         return super .overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX, scrollRangeY, maxOverScrollX, mMaxYOverscrollDistance, isTouchEvent);

     }

     

}