我有一个按钮,将其背景设置为特定的选择器.
选择器当前更改按钮背景,并将图像更改为背景.
我还希望更改背景色(图像是带有透明空间的图标).
这是选择器：

    <?xml version="1.0" encoding="utf-8"?>
        <selector 
            xmlns:android="http://schemas.android.com/apk/res/android" >
        <!-- default -->
        <item 
            android:state_pressed="false" 
            android:state_focused="false"
            android:drawable="@drawable/menu_button_collapsed" >
        </item>

        <!-- button focused -->
        <item 
            android:state_pressed="false" 
            android:state_focused="true"
            android:drawable="@drawable/menu_button_collapsed_highlight" 
            android:drawable="@drawable/button_background" >
        </item>

       <!-- button pressed -->
        <item 
            android:state_pressed="true" 
            android:state_focused="false"
            android:drawable="@drawable/menu_button_collapsed_highlight"
            android:drawable="@drawable/button_background" >
        </item>
    </selector>

如您所见,我两次设置了drawable属性,这是非法的,但这实际上是我想要的.
注意@ drawable / button_background只是一种颜色

解决方法:

创建一个新的< layer-list>可绘制

custom_button.xml

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

           <!-- Your background color goes first -->
           <item 
             android:id="@android:id/background"
             android:drawable="@drawable/button_background" />

           <!-- Your button icon image -->
           <item 
             android:id="@android:id/button_image"
             android:drawable="@drawable/menu_button_collapsed_highlight" />

        </layer-list>

并在您的选择器可绘制文件中引用它

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

        <!-- default -->
        <item 
            android:state_pressed="false" 
            android:state_focused="false"
            android:drawable="@drawable/menu_button_collapsed" 
         />            

        <!-- button focused -->
        <item 
            android:state_pressed="false" 
            android:state_focused="true"
            android:drawable="@drawable/custom_button" 
            />

        <!-- button pressed -->
        <item 
            android:state_pressed="true" 
            android:state_focused="false"
            android:drawable="@drawable/custom_button" 
         />
    </selector>