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BroadcastReceive学习例程
BroadcastReceive是Android四大核心组件之一,本质上是一种全局的监听器,用于监听系统全局的广播消息。
它用于接收程序所发出的Broadcast Intent,程序启动它只需两步:
(1)创建需要启动的ReceivecastReceiver的Intent
(2)调用Context的sendBroadcast()或sendOrderedBroastcast()方法来启动指定的BroadcastReceiver
当应用程序发出一个Broadcast Intent之后,所有匹配该Intent的BroadcastReceive都可能被启动
例程:
TestActivity.java 主页面Activity
import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; public class TestActivity extends Activity { private Button sendButton; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); sendButton = (Button)findViewById(R.id.sendButton); sendButton.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent(); intent.setAction(Intent.ACTION_EDIT); TestActivity.this.sendBroadcast(intent); } }); } }TestReceiver.java 重写BroadcastReceiver的onReceive方法
import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; public class TestReceiver extends BroadcastReceiver { public TestReceiver(){ System.out.println("TestReceive"); } @Override public void onReceive(Context context, Intent intent) { System.out.println("onReceive"); } }
AndriodManifest.xml 配置指定BroadcastReceiver能匹配的Intent
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="mars.testbc" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="18" /> <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name="mars.testbc.TestActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <receiver android:name = ".TestReceiver"> <intent-filter > <action android:name="android.intent.action.EDIT"/> </intent-filter> </receiver> </application> </manifest>
结果:点击主页面的Button(两次)
onReceive()方法执行完后,BroadcastReceive的实例就会被销毁。
BroadcastReceive学习例程
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