神奇的问题！android .9图片拉伸不是不会变形吗？但是这里变形了

Question

这是我的.9图片：

在popupwindow里头就变形了。。。
这是popupwindow的布局文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="60dp"
        android:layout_height="wrap_content"
        android:background="@drawable/menu_bg"
        android:orientation="vertical">

        <ListView
            android:id="@+id/lv_ppw_settings_lists"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:cacheColorHint="@android:color/transparent"
            android:pider="@android:color/white"
            android:piderHeight="0dp"
            android:fadingEdge="none"
            android:listSelector="@android:color/transparent">

        </ListView>

    </LinearLayout>

</LinearLayout>

Answer 1

Deformation? Isn’t this just stretching?

Answer 2

On the right, the triangle needs to be marked.

Answer 3

You need to highlight the sharp corners so that only the lower part is stretched
For details, please refer to: http://www.imooc.com/video/9363

Answer 4

You need to highlight the sharp corners so that only the lower part is stretched