android shape实现阴影或模糊边效果

1.实现阴影或模糊边效果方式：

2.通过shape来实现，具体是通过layer-list 多层叠放的方式实现的

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <layer-list xmlns:android="http://schemas.android.com/apk/res/android">
 3     <!-- 边 -->
 4     <item>
 5         <shape android:shape="rectangle">
 6             <padding
 7                 android:bottom="2dp"
 8                 android:left="2dp"
 9                 android:right="2dp"
10                 android:top="2dp" />
11             <solid android:color="#00CCCCCC" />
12             <corners android:radius="8dp" />
13         </shape>
14     </item>
15     <item>
16         <shape android:shape="rectangle">
17             <padding
18                 android:bottom="2dp"
19                 android:left="2dp"
20                 android:right="2dp"
21                 android:top="2dp" />
22             <solid android:color="#10CCCCCC" />
23             <corners android:radius="8dp" />
24         </shape>
25     </item>
26     <item>
27         <shape android:shape="rectangle">
28             <padding
29                 android:bottom="2dp"
30                 android:left="2dp"
31                 android:right="2dp"
32                 android:top="2dp" />
33             <solid android:color="#20CCCCCC" />
34             <corners android:radius="8dp" />
35         </shape>
36     </item>
37     <item>
38         <shape android:shape="rectangle">
39             <padding
40                 android:bottom="2dp"
41                 android:left="2dp"
42                 android:right="2dp"
43                 android:top="2dp" />
44             <solid android:color="#30CCCCCC" />
45             <corners android:radius="8dp" />
46         </shape>
47     </item>
48     <item>
49         <shape android:shape="rectangle">
50             <padding
51                 android:bottom="2dp"
52                 android:left="2dp"
53                 android:right="2dp"
54                 android:top="2dp" />
55             <solid android:color="#50CCCCCC" />
56             <corners android:radius="8dp" />
57         </shape>
58     </item>
59 
60     <!-- 中心背景 -->
61     <item>
62         <shape android:shape="rectangle"
63             android:useLevel="false">
64             <!-- 实心 -->
65             <solid android:color="#ffffff" />
66             <corners android:radius="10dp" />
67             <padding android:left="10dp"
68                 android:right="10dp"
69                 android:top="10dp"
70                 android:bottom="10dp"/>
71         </shape>
72     </item>
73 </layer-list>

使用：

android:background="@drawable/layer_white_bg"

顶部缩放了：android:top=2*5=10dp