metadata元数据

1 <receiver android:name=".ViewWidget" android:label="@string/app_name">
2    ....
3    <meta-data android:name="cn.android" android:value="liming"/>   
4    <meta-data android:name=“age" android:value=“30"/> 
5    <!-- 使用资源文件中存放的字符串数据 -->
6    <meta-data android:name=“other" android:value="@string/other" />
7    <!-- 使用资源的ID作为resid的值 -->
8    <meta-data android:name=“resid" android:resource="@string/resid" />
9 </receiver>

上面<meta-data>节点的可以包含在<activity> <activity-alias> <service> <receiver>四个元素中，用于为组件提供名值对数据，组件中可以定义多个<meta-data>节点，这些<meta-data>节点定义的值都会被存放在Bundle对象并作为组件PackageItemInfo.metaData字段值，要访问这些值可以这样做：

 1  ActivityInfo info = context.getPackageManager().getReceiverInfo(new ComponentName(context, ViewWidget.class), PackageManager.GET_META_DATA);
 2 
 3  String name = info.metaData.getString("cn.android");
 4 
 5  int age = info.metaData.getInt(“age");
 6 
 7  String other= info.metaData.getString("other");
 8 
 9  int id = info.metaData.getInt(“resid");
10 
11 //如果<meta-data>定义在Activity下，用getPackageManager().getActivityInfo()方法

demo:

1.清单文件

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
 3     package="com.android.hzy.metadata"
 4     android:versionCode="1"
 5     android:versionName="1.0" >
 6 
 7     <uses-sdk
 8         android:minSdkVersion="8"
 9         android:targetSdkVersion="8" />
10 
11     <application
12         android:allowBackup="true"
13         android:icon="@drawable/ic_launcher"
14         android:label="@string/app_name"
15         android:theme="@style/AppTheme" >
16         <activity
17             android:name="com.android.hzy.metadata.MainActivity"
18             android:label="@string/app_name" >
19             <intent-filter>
20                 <action android:name="android.intent.action.MAIN" />
21 
22                 <category android:name="android.intent.category.LAUNCHER" />
23             </intent-filter>
24             <meta-data android:name="name" android:value="火影忍者"/>
25             <meta-data android:name="age" android:value="7"/>
26             <meta-data android:name="other" android:value="@string/meta"/>
27             <!-- key值是一样的  value：引用的是id -->
28             <meta-data android:name="res" android:resource="@string/res"/>
29         </activity>
30     </application>
31 
32 </manifest>

2.strings.xml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <resources>
 3 
 4     <string name="app_name">元数据</string>
 5     <string name="hello_world">Hello world!</string>
 6     <string name="menu_settings">Settings</string>
 7     <string name="meta">META</string>
 8     <string name="res">resourse</string>
 9 
10 </resources>

3.MainActivity

 1 package com.android.hzy.metadata;
 2 
 3 import android.app.Activity;
 4 import android.content.ComponentName;
 5 import android.content.pm.ActivityInfo;
 6 import android.content.pm.PackageManager;
 7 import android.content.pm.PackageManager.NameNotFoundException;
 8 import android.os.Bundle;
 9 import android.util.Log;
10 import android.view.View;
11 
12 public class MainActivity extends Activity {
13 
14     @Override
15     protected void onCreate(Bundle savedInstanceState) {
16         super.onCreate(savedInstanceState);
17         setContentView(R.layout.activity_main);
18     }
19 
20     public void get(View v){
21         // activity的管理,动态的数据
22 //        ActivityManager activityManager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
23         
24         try {
25             // 包管理器
26             PackageManager pm = getPackageManager();
27             ComponentName component = new ComponentName(this,MainActivity.class);
28             
29             ActivityInfo activityInfo = pm.getActivityInfo(component, PackageManager.GET_META_DATA);
30             Bundle bundle = activityInfo.metaData;
31             String name = bundle.getString("name");
32             int age = bundle.getInt("age");
33             String other = bundle.getString("other");
34             String res = getString(bundle.getInt("res"));
35             
36             Log.i("i", " name " + name);
37             Log.i("i", " age " + age);
38             Log.i("i", " other " + other);
39             Log.i("i", " res " + res);
40             
41         } catch (Exception e) {
42             // TODO Auto-generated catch block
43             e.printStackTrace();
44         }
45     }
46 }