用RecyclerView 实现跑马灯

此方法不好，太复杂了，还是用 viewflipper之类的吧

用RecyclerView 实现跑马灯

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用 RecyclerView 实现跑马灯有几点需要注意
Recyclerview 的 smoothScrollToPosition 方法默认效果是直接滑到指定位置，看不到滑动效果，需要重写 LayoutManager 中的 smoothScrollToPosition 方法才能看到缓慢滑动的效果。

 public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, int position) {
        LinearSmoothScroller linearSmoothScroller = new LinearSmoothScroller(recyclerView.getContext()) {
            @Override
            public PointF computeScrollVectorForPosition(int targetPosition) {
                return SmoothScrolLinearLayoutManager.this
                        .computeScrollVectorForPosition(targetPosition);
            }

            //This returns the milliseconds it takes to
            //scroll one pixel.
            @Override
            protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) {
                return MILLISECONDS_PER_INCH / displayMetrics.density;
            }

        };
        linearSmoothScroller.setTargetPosition(position);
        startSmoothScroll(linearSmoothScroller);
    }

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要禁掉跑马灯的随手指滑动的效果，也要让 Recyclerview 接收点击事件。可以用以下代码实现。

   @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        if (ev.getAction() == MotionEvent.ACTION_UP) {
            ev.setAction(MotionEvent.ACTION_DOWN);
            mRv.dispatchTouchEvent(ev);
            ev.setAction(MotionEvent.ACTION_UP);
            mRv.dispatchTouchEvent(ev);
        }
        super.dispatchTouchEvent(ev);
        return true;

    }


    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        if (ev.getAction() == MotionEvent.ACTION_DOWN) {
            return true;
        }
        return super.onInterceptTouchEvent(ev);
    }

最终效果如下

screen.gif

完整的代码在此
https://github.com/frankfancode/MarqueeView