ListView 实现阻尼回弹效果并去除边缘阴影

我们使用ListView将位置拖到顶部和底部默认是没有回弹效果的，为了增加这个效果，方法如下：

1、开启overScrollMode为always
在布局中
android:overScrollMode="always"
或在代码中
setOverScrollMode(View.OVER_SCROLL_ALWAYS);

2、继承listview 覆盖overScrollBy方法，并且利用反射机制修改阴影效果为透明

public class BounceListView extends ListView {    private static final int MAX_Y_OVERSCROLL_DISTANCE = 100;     private Context mContext;    private int mMaxYOverscrollDistance;     public BounceListView(Context context) {        super(context);        mContext = context;        initBounceListView();    }     public BounceListView(Context context, AttributeSet attrs) {        super(context, attrs);        mContext = context;        initBounceListView();    }     public BounceListView(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);        mContext = context;        initBounceListView();    }     private void initBounceListView() {        // get the density of the screen and do some maths with it on the max        // overscroll distance        // variable so that you get similar behaviors no matter what the screen        // size         final DisplayMetrics metrics = mContext.getResources()                .getDisplayMetrics();        final float density = metrics.density;        mMaxYOverscrollDistance = (int) (density * MAX_Y_OVERSCROLL_DISTANCE);         //      this.setOverScrollMode(View.OVER_SCROLL_ALWAYS);                 try {            Class<?> c = (Class<?>) Class.forName(AbsListView.class.getName());            Field egtField = c.getDeclaredField("mEdgeGlowTop");            Field egbBottom = c.getDeclaredField("mEdgeGlowBottom");            egtField.setAccessible(true);            egbBottom.setAccessible(true);            Object egtObject = egtField.get(this); // this 指的是ListiVew实例            Object egbObject = egbBottom.get(this);             // egtObject.getClass() 实际上是一个 EdgeEffect 其中有两个重要属性 mGlow mEdge            // 并且这两个属性都是Drawable类型            Class<?> cc = (Class<?>) Class.forName(egtObject.getClass()                    .getName());            Field mGlow = cc.getDeclaredField("mGlow");            mGlow.setAccessible(true);            mGlow.set(egtObject, new ColorDrawable(Color.TRANSPARENT));            mGlow.set(egbObject, new ColorDrawable(Color.TRANSPARENT));             Field mEdge = cc.getDeclaredField("mEdge");            mEdge.setAccessible(true);            mEdge.set(egtObject, new ColorDrawable(Color.TRANSPARENT));            mEdge.set(egbObject, new ColorDrawable(Color.TRANSPARENT));        } catch (Exception e) {            e.printStackTrace();        }    }     @SuppressLint("NewApi")    @Override    protected boolean overScrollBy(int deltaX, int deltaY, int scrollX,            int scrollY, int scrollRangeX, int scrollRangeY,            int maxOverScrollX, int maxOverScrollY, boolean isTouchEvent) {        // This is where the magic happens, we have replaced the incoming        // maxOverScrollY with our own custom variable mMaxYOverscrollDistance;        return super.overScrollBy(deltaX, deltaY, scrollX, scrollY,                scrollRangeX, scrollRangeY, maxOverScrollX,                mMaxYOverscrollDistance, isTouchEvent);    }}

转载：

http://www.apkbus.com/android-208825-1-1.html

http://bbs.csdn.net/topics/390350587?page=1#post-393524028

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