底部弹出PopupWindow，背景变为半透明效果，采用两种方式实现
先来看看运行效果图
[方式一]实现从底部弹出PopupWindow
原理：定义一个高度为wrap_content的PopupWindow布局文件，根据屏幕底部的位置显示在Bottom
1.首先定义一个高度为wrap_content的PopupWindow布局文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://www.easck.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:padding="8dp"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:orientation="vertical"
android:background="@drawable/shape_info_bg">
<TextView android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="8dp"
android:gravity="center"
android:textColor="@color/theme_blue"
android:text="拍照"/>
<View android:layout_width="match_parent"
android:layout_height="0.2dp"
android:background="@color/theme_blue"/>
<TextView android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="8dp"
android:gravity="center"
android:textColor="@color/theme_blue"
android:text="相冊"/>
</LinearLayout>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:padding="1dp">
<Button
android:id="@+id/btn_cancle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:padding="8dp"
android:textColor="@color/theme_blue"
android:background="@drawable/shape_info_bg"
android:text="取消" />
</RelativeLayout>
</LinearLayout>
2.在PopupWindow所在的Activity根布局中声明id（在弹出PopupWindow作为位置参考的相对View）
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://www.easck.com/apk/res/android"
android:id="@+id/root_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@color/white">
<Button android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="底部弹出PopupWindow"
android:onClick="openPop"/>
<Button android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="半透明底部PopupWindow"
android:onClick="openPop2"/>
</LinearLayout>
