ScrollView拖动回弹效果(包括横向和竖向)
来源:互联网 发布:谷歌域名 编辑:程序博客网 时间:2024/05/16 14:24
原理
在android2.3版本中,View类中新增了一个方法:overScrollBy。通过覆盖该方法,就可以达到阻尼回弹的效果。
示例1、竖向滚动
- public class ReboundScrollView extends ScrollView{
- private static final int MAX_SCROLL = 200;
- private static final float SCROLL_RATIO = 0.5f;
-
- public ReboundScrollView(Context context)
- {
- super(context);
- }
-
- public ReboundScrollView(Context context, AttributeSet attrs)
- {
- super(context, attrs);
- }
-
- public ReboundScrollView(Context context, AttributeSet attrs, int defStyle)
- {
- super(context, attrs, defStyle);
- }
-
- @Override
- protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY, int scrollRangeX, int scrollRangeY, int maxOverScrollX, int maxOverScrollY, boolean isTouchEvent)
- {
- int newDeltaY = deltaY;
- int delta = (int) (deltaY * SCROLL_RATIO);
- if((scrollY+deltaY)==0 || (scrollY-scrollRangeY+deltaY)==0){
- newDeltaY = deltaY;
- }else{
- newDeltaY = delta;
- }
- return super.overScrollBy(deltaX, newDeltaY, scrollX, scrollY, scrollRangeX, scrollRangeY, maxOverScrollX, MAX_SCROLL, isTouchEvent);
- }
-
-
-
- }
示例2、横向滚动
- public class ReboundHScrollView extends HorizontalScrollView{
- private static final int MAX_SCROLL = 200;
- private static final float SCROLL_RATIO = 0.5f;
-
- public ReboundHScrollView(Context context)
- {
- super(context);
- }
-
- public ReboundHScrollView(Context context, AttributeSet attrs)
- {
- super(context, attrs);
- }
-
- public ReboundHScrollView(Context context, AttributeSet attrs, int defStyle)
- {
- super(context, attrs, defStyle);
- }
-
- @Override
- protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY, int scrollRangeX, int scrollRangeY, int maxOverScrollX, int maxOverScrollY, boolean isTouchEvent)
- {
- int newDeltaX = deltaX;
- int delta = (int) (deltaX * SCROLL_RATIO);
- if((scrollX+deltaX)==0 || (scrollX-scrollRangeX+deltaX)==0){
- newDeltaX = deltaX;
- }else{
- newDeltaX = delta;
- }
- return super.overScrollBy(newDeltaX, deltaY, scrollX, scrollY, scrollRangeX, scrollRangeY, MAX_SCROLL, maxOverScrollY, isTouchEvent);
- }
- }
0 0