Android仿天猫横向滑动指示器功能的实现

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <corners android:radius="5dp" />
    <solid android:color="@color/gray_9" />
</shape>

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <corners android:radius="5dp"/>
    <solid android:color="@color/red"/>
</shape>

 <androidx.recyclerview.widget.RecyclerView
         android:id="@+id/recycler_view"
         android:layout_width="0dp"
         android:layout_height="@dimen/dp_120"
         android:layout_marginBottom="@dimen/dp_10"/>

  <RelativeLayout
        android:id="@+id/rl_indicator"
        android:layout_width="60dp"
        android:layout_height="4dp"
        android:layout_marginTop="10dp"
        android:layout_gravity="center_horizontal"
        android:background="@drawable/indicator_bg_normal">
        <View
            android:id="@+id/main_line"
            android:layout_width="30dp"
            android:layout_height="4dp"
            android:layout_centerVertical="true"
            android:background="@drawable/indicator_bg_select"/>
  </RelativeLayout>

 rvMenu.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);

            }

            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                int range=0;
                int temp = rvMenu.computeHorizontalScrollRange();
                if (temp > range) {
                    range = temp;
                }
                //滑块的偏移量
                int offset = rvMenu.computeHorizontalScrollOffset();
                //可视区域长度
                int extent = rvMenu.computeHorizontalScrollExtent();
                //滑出部分在剩余范围的比例
                float proportion = (float) (offset * 1.0 / (range - extent));
                //计算滚动条宽度
                float transMaxRange = rlIndicator.getWidth() - mainLine.getWidth();
                //设置滚动条移动
                mainLine.setTranslationX(transMaxRange * proportion);
            }
        });