使用`TRANSPORT_CELLULAR`时,ConnectionManager不提供网络回调

Question

我试图在手机的蜂窝数据连接发生变化时接收回叫.我基本上需要知道它何时关闭以及何时打开.

我用的做到这一点TelephonyManager和PhoneStateListener.LISTEN_SERVICE_STATE,但现在我想用ConnectionManager用registerNetworkCallback.

以下代码示例已在Android Emulator(API 28),A HUAWEI P20 Lite(API 26),HTC One M8(API 23)和Motorola G6(API 26)上进行了尝试.当我打开/关闭移动数据或激活飞行模式时,他们都没有调用任何回调.

人们说这应该有效.

    NetworkRequest.Builder builder = new NetworkRequest.Builder();

    builder.addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET);
    builder.addTransportType(NetworkCapabilities.TRANSPORT_CELLULAR);

    connManager.registerNetworkCallback(builder.build(), new ConnectivityManager.NetworkCallback() {
        @Override
        public void onAvailable(Network network) {
            Log.d("Conman Test", "onAvailable");
        }

        @Override
        public void onLost(Network network) {
            Log.d("Conman Test", "onLost");
        }

        @Override
        public void onUnavailable() {
            Log.d("Conman Test", "onUnavailable");
        }

        @Override
        public void onCapabilitiesChanged(Network network, NetworkCapabilities networkCapabilities) {
            Log.d("Conman Test", "onCapabilitiesChanged");
        }

        @Override
        public void onLinkPropertiesChanged(Network network, LinkProperties linkProperties) {
            Log.d("Conman Test", "onLinkPropertiesChanged");
        }
    });

我试过了NetworkCapabilities.TRANSPORT_WIFI,它在所有设备上运行良好.那为什么不NetworkCapabilities.TRANSPORT_CELLULAR呢？

Answer 1

我没有尝试使用 解决此问题NetworkCapabilities，但我使用了另一种方法来确定我的设备是通过蜂窝网络还是 wifi 连接。

我刚刚注册了一个接收者

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

我添加了权限

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

然后我做了以下事情

public class NetworkChangeReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        ConnectivityManager cm =
                (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);

        NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
        boolean isConnected = activeNetwork != null &&
                activeNetwork.isConnectedOrConnecting();

        if(activeNetwork ==null){
            Log.d("Connectivity","Not connected");
            return;
        }

        boolean isWiFi = activeNetwork.getType() == ConnectivityManager.TYPE_WIFI;

        if(isConnected  && isWiFi){
            Log.d("Connectivity","WIFI");
        }else{
            Log.d("Connectivity","CELLULAR");
        }
    }
}

对于 Oreo 设备，您可能需要在活动或服务中注册接收器，而不是在清单中注册

举个例子

public class MainActivity extends Activity {

    IntentFilter filter1;

    @Override
    public void onCreate() {
        filter1 = new IntentFilter("android.net.conn.CONNECTIVITY_CHANGE");
        registerReceiver(myReceiver, filter1);
    }

    //The BroadcastReceiver that listens for network change
    private final BroadcastReceiver myReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            if(intent.getAction().equalsIgnoreCase("android.net.conn.CONNECTIVITY_CHANGE")) {
                Log.d(TAG,"connectivity change");

             ConnectivityManager cm =
            (ConnectivityManager)this.getSystemService(Context.CONNECTIVITY_SERVICE);

        NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
        boolean isConnected = activeNetwork != null &&
                activeNetwork.isConnectedOrConnecting();

        if(activeNetwork ==null){
            Log.d("Connectivity","Not connected");
            return;
        }

        boolean isWiFi = activeNetwork.getType() == ConnectivityManager.TYPE_WIFI;

        if(isConnected  && isWiFi){
            Log.d("Connectivity","WIFI");
        }else{
            Log.d("Connectivity","CELLULAR");
        }
            }
        }
    };

    @Override
    public void onDestroy() {
        unregisterReceiver(myReceiver);
    }
}