Android 列表多选对话框

<LinearLayout xmlns:android="https://schemas.android.com/apk/res/android"
    xmlns:tools="https://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.test11.MainActivity" >

   <Button 
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:text="btn1"
       android:onClick="btn1Onclick"/>

</LinearLayout>
<LinearLayout xmlns:android="https://