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;// 阻尼系数
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; //回弹最后一次滚动，复位
}else{
newDeltaY = delta; //增加阻尼效果
}
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;// 阻尼系数
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; //回弹最后一次滚动，复位
}else{
newDeltaX = delta; //增加阻尼效果
}
return super.overScrollBy(newDeltaX, deltaY, scrollX, scrollY, scrollRangeX, scrollRangeY, MAX_SCROLL, maxOverScrollY, isTouchEvent);
}
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。
