<meta-data>的使用

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.need88.apptests">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <meta-data android:name="str1" android:value="activity meta"/>

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <service android:name=".service.MyService">
            <meta-data android:name="str3" android:value="service meta"/>
        </service>

        <receiver android:name=".broadcastReceiver.MyReceiver">
            <intent-filter>
                <action android:name="android.intent.action.PHONE_STATE"/>
            </intent-filter>
            <meta-data android:name="str4" android:value="receiver meta"/>
        </receiver>


        <meta-data android:name="str2" android:value="application meta"/>


    </application>

</manifest>

核心代码

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        try {
            //获取Activity中的元数据
            ActivityInfo activityInfo = getPackageManager().getActivityInfo(getComponentName(), PackageManager.GET_META_DATA);
            String msg_activity = activityInfo.metaData.getString("str1");
            Log.d("wl",getComponentName()+"的元数据是: "+ msg_activity);

            //获取Application 中的元数据
            ApplicationInfo applicationInfo = getPackageManager().getApplicationInfo(getPackageName(), PackageManager.GET_META_DATA);
            String msg_applic = applicationInfo.metaData.getString("str2");
            Log.d("wl",getPackageName()+"的元数据是: "+ msg_applic);

            //获取service中的元数据
            ComponentName componentName = new ComponentName(this, MyService.class);
            ServiceInfo serviceInfo = getPackageManager().getServiceInfo(componentName, PackageManager.GET_META_DATA);
            String msg_service = serviceInfo.metaData.getString("str3");
            Log.d("wl",componentName+"的元数据是: "+ msg_service);

            //在 Receiver中的应用
            ComponentName receiver = new ComponentName(this, MyReceiver.class);
            //没有 ReceiverInfo 类
            ActivityInfo info = getPackageManager().getReceiverInfo(receiver, PackageManager.GET_META_DATA);
            String msg_receiver = info.metaData.getString("str4");
            Log.d("wl",receiver+"的元数据是: "+ msg_receiver);


        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }

    }
}