Android 学习之获取application和activity下meta-data中的值

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meta-data在AndroidManifest中是以键值对的形式存在的，可以将meta-data放在application根节点下，也可以放在某个activity节点下。因为存放的位置不同，因此获取value时也要使用对应的方法，下面是我写的一个小测试。

代码如下：

先是在AndroidManifest中的application和mainActivity下添加两个meta-data属性。

    <application        android:allowBackup="true"        android:icon="@drawable/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <meta-data            android:name="com.lzy.test"            android:value="测试" />        <activity            android:name=".MainActivity"            android:label="@string/app_name" >            <meta-data                android:name="com.example.metatest.MainActivity.com.lzy.activity.test"                android:value="Activity测试" />            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>    </application>

接下来在mainActivity中来获取这两个属性的值。

package com.example.metatest;import android.app.Activity;import android.content.ComponentName;import android.content.pm.ActivityInfo;import android.content.pm.ApplicationInfo;import android.content.pm.PackageManager;import android.content.pm.PackageManager.NameNotFoundException;import android.os.Bundle;import android.util.Log;import android.widget.Toast;/** * meta 测试 *  * @author Administrator *  */public class MainActivity extends Activity {public static final String TEST = "com.lzy.test";public static final String ACTIVITYTEST = MainActivity.class.getName()+".com.lzy.activity.test";@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);String test = getMetaDataStringApplication(TEST, null);String activityTest = getMetaDataStringFromActivity(ACTIVITYTEST, null);Toast.makeText(this, test+"--"+activityTest, Toast.LENGTH_LONG).show();}/** * 根据key从Application中返回的Bundle中获取value *  * @param key * @param defValue * @return */private String getMetaDataStringApplication(String key, String defValue) {Bundle bundle = getAppMetaDataBundle(getPackageManager(), getPackageName());if (bundle != null && bundle.containsKey(key)) {return bundle.getString(key);}return defValue;}/** * 获取Application中的meta-data. *  * @param packageManager * @param packageName * @return */private Bundle getAppMetaDataBundle(PackageManager packageManager,String packageName) {Bundle bundle = null;try {ApplicationInfo ai = packageManager.getApplicationInfo(packageName,PackageManager.GET_META_DATA);bundle = ai.metaData;} catch (NameNotFoundException e) {Log.e("getMetaDataBundle", e.getMessage(), e);}return bundle;}/** * 根据key从Activity中返回的Bundle中获取value *  * @param key * @param defValue * @return */private String getMetaDataStringFromActivity(String key, String defValue) {Bundle bundle = getActivityMetaDataBundle(getPackageManager(), getComponentName());if (bundle != null && bundle.containsKey(key)) {return bundle.getString(key);}return defValue;}/** * 获取Activity中的meta-data. *  * @param packageManager * @param component * @return */private Bundle getActivityMetaDataBundle(PackageManager packageManager, ComponentName component) {Bundle bundle = null;try {ActivityInfo ai = packageManager.getActivityInfo(component,PackageManager.GET_META_DATA);bundle = ai.metaData;} catch (NameNotFoundException e) {Log.e("getMetaDataBundle", e.getMessage(), e);}return bundle;}}

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