我要翻转图像按钮的背景XML。我见过的例子，如何做到这一点，但它是通过编程的方式：http://xjaphx.word$p$pss.com/2011/06/26/image-processing-image-flipping-mirroring. 无论如何，我有一个XML文件（button_left_state.xml）如下图所示：

I want to flip image for button's background in xml. I've seen example how to do it, but it was programmatically way: http://xjaphx.wordpress.com/2011/06/26/image-processing-image-flipping-mirroring. Anyway, I have a xml file (button_left_state.xml) like below :

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">  
<item android:state_pressed="true" >
    <rotate android:fromDegrees="180.0" android:toDegrees="180.0" 
    android:pivotX="50%" android:pivotY="50%" android:drawable="@drawable/buttonrightpressed" />    
</item>    

<item>
  <rotate android:fromDegrees="180.0" android:toDegrees="0.0" 
    android:pivotX="50%" android:pivotY="50%" android:drawable="@drawable/buttonright"/>
</item>   
</selector>

但是，这code只需旋转图像180度。 是否可以翻转图像在XML？

But this code just rotate image to 180 degrees. Is it possible to flip image in xml?

推荐答案

我解决我的问题，通过使用图层列表：

I resolve my problem by using layer-list:

<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item > 
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">    
<item>    
    <shape android:shape="rectangle">        
          <gradient android:startColor="#9f9" android:centerColor="#000" 
                    android:endColor="#0f0" android:angle="-90" />
          <stroke android:width="1.0px" android:color="#444" />   
           <corners android:bottomRightRadius="7dip"
            android:bottomLeftRadius="0.1dp"
            android:topLeftRadius="0.1dp"
            android:topRightRadius="7dip"/>               
     </shape>
</item>
<item>
  <rotate android:fromDegrees="180.0" android:toDegrees="180.0" 
    android:pivotX="50%" android:pivotY="50%" android:drawable="@drawable/arrow_right" />
</item>