android 48 广播

系统开始重启会发送开机重启广播，电量低的时候会发送电量低的广播，广播注册有2种:系统说明文件xml注册和Java代码注册，前者是静态注册(全局注册)后者是动态注册（依赖于当时组建，组件销毁就收不到广播了）。

package com.sxt.day07_04;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;

public class MainActivity extends Activity {
MyReceiver2 mReceiver;

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

private void setListener() {
sendBroadcast1ClickListener();
sendBroadcast2ClickListener();
}

private void sendBroadcast2ClickListener() {
findViewById(R.id.btnSendBroadcast_2).setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
Intent intent=new Intent("com.sxt.day07_04.MyReceiver2");//
intent.putExtra("key", "hello android!");
sendBroadcast(intent);
}
});
}

private void sendBroadcast1ClickListener() {
findViewById(R.id.btnSendBroadcast_1).setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
Intent intent=new Intent("com.sxt.day07_04.MyReceiver1");
intent.putExtra("key", "hello java!");
sendBroadcast(intent);
}
});
}

//java类注册的广播接收者
private void registerReceiver() {
mReceiver=new MyReceiver2();
IntentFilter filter=new IntentFilter();//意图过滤器
filter.addAction("com.sxt.day07_04.MyReceiver2");//广播的字符串
registerReceiver(mReceiver, filter);
}

class MyReceiver2 extends BroadcastReceiver{
@Override
//收到广播执行的方法
public void onReceive(Context context, Intent intent) {
Log.i("main","MyReceiver2.onReceive():"+intent.getStringExtra("key"));
}
}

@Override
protected void onDestroy() {
super.onDestroy();
//Activity退出的时候取消广播的注册，释放资源.
unregisterReceiver(mReceiver);
}
}

package com.sxt.day07_04;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

public class MyReceiver1 extends BroadcastReceiver {

@Override
//收到广播后执行的方法
public void onReceive(Context context, Intent intent) {
Log.i("main","MyReceiver1.onReceive():"+intent.getStringExtra("key"));
}

}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.sxt.day07_04"
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="com.sxt.day07_04.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>
注册全局广播接收者
<receiver android:name="com.sxt.day07_04.MyReceiver1">   广播接收者类
<intent-filter>
<action android:name="com.sxt.day07_04.MyReceiver1"/>   广播的字符串是这个就可以接收广播
</intent-filter>
</receiver>
</application>

</manifest>