1.创建一个Module命名为NumberAddSubView
2.创建自定义控件的布局文件number_add_sub_view.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/number_add_sub_view_selector"
    android:gravity="center_vertical"
    android:orientation="horizontal">

    <Button
        android:id="@+id/btn_sub"
        android:layout_width="40dp"
        android:layout_height="wrap_content"
        android:background="@drawable/btn_number_selector"
        android:gravity="center"
        android:text="-"
        android:textColor="@android:color/black"
        android:textSize="25sp" />

    <TextView
        android:layout_width="40dp"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="1"
        android:textColor="@android:color/black"
        android:textSize="20sp" />

    <Button
        android:id="@+id/btn_add"
        android:layout_width="40dp"
        android:layout_height="wrap_content"
        android:background="@drawable/btn_number_selector"
        android:gravity="center"
        android:text="+"
        android:textColor="@android:color/black"
        android:textSize="25sp" />
</LinearLayout>

3.布局中用到控件的选择器，整体布局的边框线number_add_sub_view_selector.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
    <!--设置圆角-->
    <corners android:radius="2dp"></corners>
    <!--设置固定背景颜色-->
    <solid android:color="#ffffff"></solid>
    <!--设置边框颜色-->
    <stroke android:color="#dddddd" android:width="1dp"></stroke>
</shape>

按钮控件的按下背景颜色选择器btn_number_selector.xml

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

    <!--没按下状态-->
    <item android:state_enabled="false">
        <shape android:shape="rectangle">
            <corners