Android学习之Broadcast的简单使用

package com.example.luobo.broadcasttest;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.net.ConnectivityManager;import android.net.NetworkInfo;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.widget.Toast;public class MainActivity extends AppCompatActivity { private IntentFilter intentFilter; private NetworkChangeReceiver networkChangeReceiver; @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  intentFilter = new IntentFilter();//创建一个过滤器实例  intentFilter.addAction("android.net.conn.CONNECTIVITY_CHANGE");//添加接收CONNECTIVITY_CHANGE消息  networkChangeReceiver = new NetworkChangeReceiver();  registerReceiver(networkChangeReceiver,intentFilter); } @Override protected void onDestroy() {  super.onDestroy();  unregisterReceiver(networkChangeReceiver); } class NetworkChangeReceiver extends BroadcastReceiver{  @Override  public void onReceive(Context context, Intent intent) {   ConnectivityManager connectivityManager = (ConnectivityManager)     getSystemService(Context.CONNECTIVITY_SERVICE);//通过此方法获取ConnectivityManager实例   NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();//调用实例connectivityManager的getActiveNetworkInfo()方法获取NetworkInfo实例   if (networkInfo != null && networkInfo.isAvailable()){    Toast.makeText(context,"Network is available",Toast.LENGTH_SHORT).show();   }else {    Toast.makeText(context,"Network is unavailable",Toast.LENGTH_SHORT).show();   }  } }}

package com.example.luobo.broadcasttest;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.widget.Toast;public class BootCompleteReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) {  Toast.makeText(context,"Boot Complete",Toast.LENGTH_SHORT).show(); }}

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.luobo.broadcasttest"> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />//注册接收网络消息广播 <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>//注册接收开机启动广播 <application  android:allowBackup="true"  android:icon="@mipmap/ic_launcher"  android:label="@string/app_name"  android:roundIcon="@mipmap/ic_launcher_round"  android:supportsRtl="true"  android:theme="@style/AppTheme">  <activity android:name=".MainActivity">   <intent-filter>    <action android:name="android.intent.action.MAIN" />    <category android:name="android.intent.category.LAUNCHER" />   </intent-filter>  </activity>  <receiver   android:name=".BootCompleteReceiver"   android:enabled="true"   android:exported="true">   <intent-filter>    <action android:name="android.intent.action.BOOT_COMPLETED"/>//开机时系统会发一条此广播   </intent-filter>  </receiver> </application></manifest>