Android利用系统广播---监听网络变化

package mark.zhang;

import android.app.Service;
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.os.IBinder;
import android.util.Log;

public class ListenNetStateService extends Service {
private ConnectivityManager connectivityManager;
private NetworkInfo info;

private BroadcastReceiver mReceiver = new BroadcastReceiver() {

@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (action.equals(ConnectivityManager.CONNECTIVITY_ACTION)) {
Log.d("mark", "网络状态已经改变");
connectivityManager = (ConnectivityManager)

getSystemService(Context.CONNECTIVITY_SERVICE);
info = connectivityManager.getActiveNetworkInfo();
if(info != null && info.isAvailable()) {
String name = info.getTypeName();
Log.d("mark", "当前网络名称：" + name);
} else {
Log.d("mark", "没有可用网络");
}
}
}
};

@Override
public IBinder onBind(Intent intent) {
return null;
}

@Override
public void onCreate() {
super.onCreate();
IntentFilter mFilter = new IntentFilter();
mFilter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
registerReceiver(mReceiver, mFilter);
}

@Override
public void onDestroy() {
super.onDestroy();
unregisterReceiver(mReceiver);
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
return super.onStartCommand(intent, flags, startId);
}
}

在 manifest 文件中需要加上一条权限：

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

回头再看看关于 CONNECTIVITY_ACTION 的介绍，从 api 中，我们还可以得到一个信息：

通过 intent 可以获取一些 EXTRA，如 EXTRA_NO_CONNECTIVITY。

boolean b = intent.getBooleanExtra(ConnectivityManager.EXTRA_NO_CONNECTIVITY, true);

更多信息可以参考 ConnectivityManager.

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在Android操作系统中，如何能够正确的判断我们所连接的网络是否断开恩？今天我们就针对这一应用技巧进行一个详细的分析。

public class ConnectionChangeReceiver extends BroadcastReceiver {
@Override
public void onReceive( Context context, Intent intent ) {
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetInfo = connectivityManager.getActiveNetworkInfo();
NetworkInfo mobNetInfo = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
if ( activeNetInfo != null ) {
Toast.makeText( context, "Active Network Type : " +
activeNetInfo.getTypeName(), Toast.LENGTH_SHORT ).show();
}
if( mobNetInfo != null ) {
Toast.makeText( context, "Mobile Network Type : " +
mobNetInfo.getTypeName(), Toast.LENGTH_SHORT ).show();
}
}
}

< !-- Needed to check when the network connection changes -->

< uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
< receiver android:name="com.blackboard.androidtest.receiver.ConnectionChangeReceiver"
android:label="NetworkConnection">
< intent-filter>
< action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>
< /intent-filter>
< /receiver>