定制评级栏？(Custom rating bar?)

 我有一个布局。我在其中嵌入了一个自定义评级栏： 
 
<RatingBar
            android:id="@id/rate"
            style="?android:attr/ratingBarStyleSmall"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginRight="5.0dip"
            android:isIndicator="true"
            android:max="5"
            android:numStars="5"
            android:progressDrawable="@drawable/ratebar_theme"
            android:stepSize="0.1" />
 
 它是ratebar_theme ： 
 
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >

    <item
        android:id="@android:id/background"
        android:drawable="@drawable/star_empty_show"/>

    <item
        android:id="@android:id/secondaryProgress"
        android:drawable="@drawable/star_empty_show"/>

    <item
        android:id="@android:id/progress"
        android:drawable="@drawable/star_filled_show"/>

</layer-list>
 
 star_empty_show和star_filled_show都是star_filled_show的drawable文件夹中的.png文件。上面的代码没有错误，但在Graphical layout选项卡中我看到： 
 
Failed to parse file E:\...\res\drawable\ratebar_theme.xml
 
 在Error Log我看到了这个： 
 
  org.xmlpull.v1.XmlPullParserException: Binary XML file line #6: <item> tag requires a 'drawable' attribute or child tag defining a drawable
 
 但我已经为每个drawable添加了drawable属性。是否知道为什么会出现这个错误？ 

I have a layout.I have embedded a custom rating bar in it:
 
<RatingBar
            android:id="@id/rate"
            style="?android:attr/ratingBarStyleSmall"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginRight="5.0dip"
            android:isIndicator="true"
            android:max="5"
            android:numStars="5"
            android:progressDrawable="@drawable/ratebar_theme"
            android:stepSize="0.1" />
 
It is ratebar_theme:
 
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >

    <item
        android:id="@android:id/background"
        android:drawable="@drawable/star_empty_show"/>

    <item
        android:id="@android:id/secondaryProgress"
        android:drawable="@drawable/star_empty_show"/>

    <item
        android:id="@android:id/progress"
        android:drawable="@drawable/star_filled_show"/>

</layer-list>
 
Both star_empty_show and star_filled_show are .png files in drawable folder of project.Both above codes have no error,but in Graphical layout tab I see this:
 
Failed to parse file E:\...\res\drawable\ratebar_theme.xml
 
And in Error Log I see this:
 
  org.xmlpull.v1.XmlPullParserException: Binary XML file line #6: <item> tag requires a 'drawable' attribute or child tag defining a drawable
 
But I have add drawable attribute to each item.Do ypu know why this error occures?

原文：https://stackoverflow.com/questions/14439523