android - android.support.v4.widget.CircleImageView不起作用

当我尝试使用时:
android.support.v4.widget.CircleImageView

        <android.support.v4.widget.CircleImageView
                android:id="@+id/picture"
                android:layout_width="100dp"
                android:layout_height="100dp"
                android:layout_gravity="center_vertical"
                android:src="@drawable/ic_bg" />

这会使我的应用崩溃

如何支持新的Material Design小部件CircleImageView

有没有使用此新小部件的示例

Logcat

  java.lang.RuntimeException: Unable to start activity ComponentInfo{com.vogella.android.recyclerview/com.vogella.android.recyclerview.MainActivity}: android.view.InflateException: Binary XML file line #9: Error inflating class android.support.v4.widget.CircleImageView
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2255)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2309)
        at android.app.ActivityThread.access$700(ActivityThread.java:157)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1289)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:176)
        at android.app.ActivityThread.main(ActivityThread.java:5317)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:511)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
        at dalvik.system.NativeStart.main(Native Method)
 Caused by: android.view.InflateException: Binary XML file line #9: Error inflating class android.support.v4.widget.CircleImageView
        at

最佳答案

CircleImageView是支持库的私有(private)类，不能使用。但是，无需CircleImageView即可轻松创建此效果。您只需要定义一个<shape />可绘制对象，中间带有一个透明圆圈，如下所示:

<shape
    android:innerRadius="0dp"
    android:shape="ring"
    android:thicknessRatio="1"
    android:useLevel="false" >

    <solid android:color="@android:color/transparent" />

    <stroke
        android:width="100dp"
        android:color="#FFFFFFFF" />
</shape>

之后，只需将要显示在ImageView中的图像与可从上方以<shape />绘制的LayerList相结合即可，如下所示:

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/your_image" />
    <item android:drawable="@drawable/circle" />
</layer-list>

如果要显示的图像是动态的，则可以通过编程方式创建LayerList!