Android_08_使用服务注册广播

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MainActivity.java

package com.itheima.register;import android.os.Bundle;import android.app.Activity;import android.content.Intent;import android.view.Menu;import android.view.View;public class MainActivity extends Activity {    private Intent intent;@Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        intent = new Intent(this, RegisterService.class);    }    public void start(View v){    startService(intent);    }    public void stop(View v){    stopService(intent);    }    }

RegisterService.java

package com.itheima.register;import android.app.Service;import android.content.Intent;import android.content.IntentFilter;import android.os.IBinder;public class RegisterService extends Service {private ScreenReceiver receiver;@Overridepublic IBinder onBind(Intent intent) {// TODO Auto-generated method stubreturn null;}@Overridepublic void onCreate() {super.onCreate();//1.创建广播接收者对象receiver = new ScreenReceiver();//2.创建intent-filter对象IntentFilter filter = new IntentFilter();filter.addAction(Intent.ACTION_SCREEN_OFF);filter.addAction(Intent.ACTION_SCREEN_ON);//3.注册广播接收者registerReceiver(receiver, filter);}@Overridepublic void onDestroy() {super.onDestroy();//解除注册unregisterReceiver(receiver);}}

ScreenReceiver.java

package com.itheima.register;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;public class ScreenReceiver extends BroadcastReceiver {@Overridepublic void onReceive(Context context, Intent intent) {// TODO Auto-generated method stubString action = intent.getAction();if(Intent.ACTION_SCREEN_OFF.equals(action)){System.out.println("屏幕关闭");}else if(Intent.ACTION_SCREEN_ON.equals(action)){System.out.println("屏幕打开");}}}

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context=".MainActivity" >    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="启动服务"         android:onClick="start"        />    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="停止服务"         android:onClick="stop"        /></LinearLayout>

清单文件：

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.itheima.register"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk        android:minSdkVersion="8"        android:targetSdkVersion="17" />    <application        android:allowBackup="true"        android:icon="@drawable/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <activity            android:name="com.itheima.register.MainActivity"            android:label="@string/app_name" >            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>        <service android:name="com.itheima.register.RegisterService"></service>    </application></manifest>

注：

服务必须在清单文件中注册，但广播既可以在清单文件中注册，也可以在代码中注册；

广播在代码中注册的好处就是，当我需要侦听广播的时候，我就注册，当我不需要侦听

广播的时候，我就解除注册，这样我就不会再接收到相应的广播了！而在清单文件中

注册的广播，当你开启之后，它会一直侦听；

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