Android 监听wifi, 3g的开、关

private BroadcastReceiver mConnReceiver = new BroadcastReceiver() {  
        @Override  
        public void onReceive(Context context, Intent intent) {  
  
            boolean isWifiConnected = false;  
            boolean isMobileConnected = false;  
  
            ConnectivityManager connMgr = (ConnectivityManager)   
                    context.getSystemService(Context.CONNECTIVITY_SERVICE);  
  
            NetworkInfo networkInfo = connMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI);  
  
            if(networkInfo != null)  
            isWifiConnected = networkInfo.isConnected();  
  
            networkInfo = connMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);  
  
            if(networkInfo != null)  
            isMobileConnected = networkInfo.isConnected();        
  
            Log.d("network status", "wifi == " + isWifiConnected + " and mobile == " + isMobileConnected);  
  
        }  
    };  

registerReceiver(mConnReceiver,   
           new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION));  

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