@Override 
public void onReceive(Context context, Intent intent) { 
ConnectivityManager manager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE); 
 NetworkInfo gprs = manager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE); 
NetworkInfo wifi = manager.getNetworkInfo(ConnectivityManager.TYPE_WIFI); 
if (intent.getAction().equals("Android.net.conn.CONNECTIVITY_CHANGE"))  { 
//移动数据连接上时 
if (gprs.isConnected()){ 
} 
//wifi连接上时 
if (wifi.isConnected()) { 
// 切换网络，关闭wifi，开启流量 
if (isShow) {//做一个标记，避免多次弹窗的叠加bug，初始值为true，重要 
switchNetwork(context); 
}  
} 
//断网时 
if (!netManager.getGRPS().isConnected() || !netManager.getGRPS().isConnected()) { 
}   
} 

private void switchNetwork(final Context context) { 
AlertDialog.Builder builder = new AlertDialog.Builder(context, R.style.AlertDialog); 
builder.setTitle("提示"); 
builder.setMessage("请关闭wifi，打开移动网络"); 
builder.setCancelable(false); 
builder.setPositiveButton("确定", new DialogInterface.OnClickListener() { 
@Override 
public void onClick(DialogInterface dialog, int which) { 
// 控制网络的开关 
controlNetWork(context); 
isShow = true; 
} 
}); 
AlertDialog dialog = builder.create(); 
// 需要把对话框的类型设为TYPE_SYSTEM_ALERT，否则对话框无法在广播接收器里弹出 
dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT); 
dialog.show(); 
isShow = false; 
} 

private void controlNetWork(Context context) { 
    WifiManager wifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE); 
      // 允许流量，阻止wifi 
      wifiManager.setWifiEnabled(false);//false表示断开WiFi 
      NetManager netManager = new NetManager(context); 
      if (!netManager.getGRPS().isConnected()) { 
        ConnectivityManager gprsCM = (ConnectivityManager) context 
            .getSystemService(Context.CONNECTIVITY_SERVICE); 
        Class conmanClass; 
        try { 
          conmanClass = Class.forName(gprsCM.getClass().getName()); 
          final Field iConnectivityManagerField = conmanClass.getDeclaredField("mService"); 
iConnectivityManagerField.setAccessible(true); 
          final Object iConnectivityManager = iConnectivityManagerField.get(gprsCM); 
          final Class iConnectivityManagerClass = Class.forName(iConnectivityManager.getClass().getName()); 
          final Method setMobileDataEnabledMethod = iConnectivityManagerClass 
              .getDeclaredMethod("setMobileDataEnabled", Boolean.TYPE); 
setMobileDataEnabledMethod.setAccessible(true);//true表示连接网络 
          setMobileDataEnabledMethod.invoke(iConnectivityManager, true); 
        } catch (Exception e) { 
          e.printStackTrace(); 
        } 
      } 
    } 
  } 

<receiver 
      android:name=".NetChangeReceiver" 
      android:label="NetChangeReceiver" > 
      <intent-filter> 
        <action android:name="android.net.conn.CONNECTIVITY_CHANGE" /> 
      </intent-filter> 
</receiver> 

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