Android实现无限循环滚动

public class LoopView extends ViewGroup {
  private static final String TAG = "LoopView";
  private float dis;
  private ObjectAnimator animator;
  private int currentIndex = 0;
  private Handler handler = new Handler(Looper.getMainLooper());
 
  public LoopView(Context context) {
    super(context);
    init();
  }
 
  public LoopView(Context context, AttributeSet attrs) {
    super(context, attrs);
    init();
  }
 
  public LoopView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    init();
  }
 
  void init() {
    View view1 = new View(getContext());
    view1.setTag("gray");
    view1.setBackgroundColor(Color.GRAY);
    LayoutParams layoutParams = new LayoutParams(LayoutParams.MATCH_PARENT, 200);
    addView(view1, layoutParams);
 
    View view2 = new View(getContext());
    view2.setTag("red");
    view2.setBackgroundColor(Color.RED);
    LayoutParams layoutParams1 = new LayoutParams(LayoutParams.MATCH_PARENT, 200);
    addView(view2, layoutParams1);
 
    View view3 = new View(getContext());
    view3.setTag("green");
    view3.setBackgroundColor(Color.GREEN);
    LayoutParams layoutParams2 = new LayoutParams(LayoutParams.MATCH_PARENT, 200);
    addView(view3, layoutParams2);
 
    animator = ObjectAnimator.ofFloat(this, "dis", 0, 1);
    animator.setDuration(2000);
    animator.addListener(new AnimatorListenerAdapter() {
      @Override
      public void onAnimationEnd(Animator animation) {
        currentIndex++;
        View first = getChildAt(0);
        removeView(first);
        addView(first);
        handler.postDelayed(new Runnable() {
          @Override
          public void run() {
            animator.clone().start();
          }
        }, 3000);
      }
    });
 
  }
 
  public void start() {
    animator.start();
  }
 
  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    measureChildren(widthMeasureSpec, heightMeasureSpec);
    super.onMeasure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(200, MeasureSpec.EXACTLY));
  }
 
  @Override
  protected void onLayout(boolean changed, int l, int t, int r, int b) {
    int childCount = getChildCount();
    int top = currentIndex * getMeasuredHeight();
    for (int i = 0; i < childCount; i++) {
      View childAt = getChildAt(i);
      childAt.layout(l, top, r, top + childAt.getMeasuredHeight());
      top += childAt.getMeasuredHeight();
    }
  }
 
  public float getDis() {
    return dis;
  }
 
  public void setDis(float dis) {
    this.dis = dis;
    float disY = dis * getHeight();
    scrollTo(0, (int) (currentIndex * getHeight() + disY));
  }
}