ImageView不会在使用layer-list作为背景的LinearLayout中显示

I have the following layer-list

我有以下图层列表

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


    <item>
        <shape xmlns:android="https://schemas.android.com/apk/res/android">
            <solid android:color="#FF000000"/>
            <stroke android:width="0dp" android:color="#FF000000" />
            <corners android:topLeftRadius="10dp" android:topRightRadius="10dp"/>
            <padding android:left="0dp" android:top="0dp" android:right="0dp" android:bottom="0dp" />
        </shape>
    </item>

</layer-list>
<?