Android界面上拉下拉的回弹效果实例代码

废话不多说，具体代码如下所示：

public class myscrollview extends scrollview {
  private view childview;
  public myscrollview(context context) {
    super(context);
  }
  public myscrollview(context context, attributeset attrs) {
    super(context, attrs);
  }
  public myscrollview(context context, attributeset attrs, int defstyleattr) {
    super(context, attrs, defstyleattr);
  }
//  @override
//  protected void onlayout(boolean changed, int l, int t, int r, int b) {
//    super.onlayout(changed, l, t, r, b);
//  }
  //获取子视图
  @override
  protected void onfinishinflate() {
    super.onfinishinflate();
    if (getchildcount() > 0) {
      childview = getchildat(0);
    }
  }
  private int lasty;//上一次y轴方向操作的坐标位置
  private rect normal = new rect();//用于记录临界状态的左、上、右、下
  private boolean isfinishanimation = true;//是否动画结束
  private int lastx, downx, downy;
  //拦截:实现父视图对子视图的拦截
  //是否拦截成功，取决于方法的返回值。返回值true:拦截成功。反之，拦截失败
  @override
  public boolean onintercepttouchevent(motionevent ev) {
    boolean isintercept = false;
    int eventx = (int) ev.getx();
    int eventy = (int) ev.gety();
    switch (ev.getaction()) {
      case motionevent.action_down:
        lastx = downx = eventx;
        lasty = downy = eventy;
        break;
      case motionevent.action_move:
        //获取水平和垂直方向的移动距离
        int absx = math.abs(eventx - downx);
        int absy = math.abs(eventy - downy);
        if(absy > absx && absy >= uiutils.dp2px(10)){
          isintercept = true;//执行拦截
        }
        lastx = eventx;
        lasty = eventy;
        break;
    }
    return isintercept;
  }
  @override
  public boolean ontouchevent(motionevent ev) {
    if (childview == null || !isfinishanimation) {
      return super.ontouchevent(ev);
    }
    int eventy = (int) ev.gety();//获取当前的y轴坐标
    switch (ev.getaction()) {
      case motionevent.action_down:
        lasty = eventy;
        break;
      case motionevent.action_move:
        int dy = eventy - lasty;//微小的移动量
        if (isneedmove()) {
          if (normal.isempty()) {
            //记录了childview的临界状态的左、上、右、下
            normal.set(childview.getleft(), childview.gettop(), childview.getright(), childview.getbottom());
          }
          //重新布局
          childview.layout(childview.getleft(), childview.gettop() + dy / 2, childview.getright(), childview.getbottom() + dy / 2);
        }
        lasty = eventy;//重新赋值
        break;
      case motionevent.action_up:
        if (isneedanimation()) {
          //使用平移动画
          int translatey = childview.getbottom() - normal.bottom;
          translateanimation translateanimation = new translateanimation(0, 0, 0, -translatey);
          translateanimation.setduration(200);
//        translateanimation.setfillafter(true);//停留在最终位置上
          translateanimation.setanimationlistener(new animation.animationlistener() {
            @override
            public void onanimationstart(animation animation) {
              isfinishanimation = false;
            }
            @override
            public void onanimationend(animation animation) {
              isfinishanimation = true;
              childview.clearanimation();//清除动画
              //重新布局
              childview.layout(normal.left, normal.top, normal.right, normal.bottom);
              //清除normal的数据
              normal.setempty();
            }
            @override
            public void onanimationrepeat(animation animation) {
            }
          });
          //启动动画
          childview.startanimation(translateanimation);
        }
        break;
    }
    return super.ontouchevent(ev);
  }
  //判断是否需要执行平移动画
  private boolean isneedanimation() {
    return !normal.isempty();
  }
  private boolean isneedmove() {
    int childmeasuredheight = childview.getmeasuredheight();//获取子视图的高度
    int scrollviewmeasuredheight = this.getmeasuredheight();//获取布局的高度
    log.e("tag", "childmeasuredheight = " + childmeasuredheight);
    log.e("tag", "scrollviewmeasuredheight = " + scrollviewmeasuredheight);
    int dy = childmeasuredheight - scrollviewmeasuredheight;//dy >= 0
    int scrolly = this.getscrolly();//获取用户在y轴方向上的偏移量 （上 + 下 -）
    if (scrolly <= 0 || scrolly >= dy) {
      return true;//按照我们自定义的myscrollview的方式处理
    }
    //其他处在临界范围内的，返回false。即表示，仍按照scrollview的方式处理
    return false;
  }
}

以上所述是小编给大家介绍的android界面上拉下拉的回弹效果实例代码，希望对大家有所帮助