android 自定义滚动条图标

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >

    <!-- 填充 -->
    <solid android:color="#37393d" /> 

    <!-- 圆角 -->
    <corners android:radius="5dp" />

<ListView
     android:id="@+id/id_msg_listview"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:divider="@null"
     android:listSelector="@android:color/transparent"
     android:scrollbarSize="@dimen/scrollbarSize"
     android:scrollbarStyle="outsideOverlay"
     android:scrollbarThumbVertical="@drawable/scrollbar_vertical_thumb"
     android:scrollbars="vertical" />