ConnectionManager在使用`TRANSPORT_CELLULAR`时不进行网络回调

Question

更新：工作：TRANSPORT_CELLULAR连接只有在TRANSPORT_WIFI断开时才可用。启用WiFi时，除非在手机的开发人员设置中启用了同时的蜂窝数据，否则不会收到回调。

每当手机的蜂窝数据连接发生变化时，我都会尝试接收回叫。我需要知道它什么时候关机，什么时候开。

我以前用TelephonyManager和PhoneStateListener.LISTEN_SERVICE_STATE来做这件事，但是现在我想在registerNetworkCallback中使用ConnectionManager。

以下代码示例已在Android模拟器(API 28)、华为P20 Lite (API 26)、HTC M8 (API 23)和摩托罗拉G6 (API 26)上试用。当我打开/关闭移动数据或激活飞机模式时，它们都不会调用任何回调。

People say this should work。

    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NetworkCapabilities.TRANSPORT_WIFI，它在所有的设备上都能正常工作。所以为什么不NetworkCapabilities.TRANSPORT_CELLULAR

Answer 1

我还没有尝试使用NetworkCapabilities来解决这个问题，但我使用了另一种方法来确定我的设备是通过蜂窝连接还是通过wifi连接。

我刚注册了一个接收器

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

我增加了许可

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

然后我做了以下工作

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");
        }
    }
}

对于奥利奥设备，您可能需要在活动或服务中注册接收器，而不是清单。

作为一个例子

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);
    }
}