在安卓12中无法使用onCapabilitiesChanged获取WIFI SSID

Question 1

Description

在Android-12中，我无法使用 onCapabilitiesChanged 中的 ConnectivityManager.NetworkCallback 类获得WIFI SSID。在Android-12中，getConnectionInfo被废弃了。因此，正如android文档所建议的，我试图使用 onCapabilitiesChanged 来获取 WifiInfo 对象。

Like this,

@Override
public void onCapabilitiesChanged(@NonNull Network network, @NonNull NetworkCapabilities networkCapabilities) {
        super.onCapabilitiesChanged(network, networkCapabilities);
        WifiInfo wifiInfo = (WifiInfo) networkCapabilities.getTransportInfo();
But, when I print the WifiInfo object. it will print SSID: <unknown ssid>和getHiddenSSID返回真。
意想不到的行为是。
Android-12设备与一个WIFI连接（如ABC）。
When I try to get WIFI SSID using getConnectionInfo. it return
SSID: ABC and getHiddenSSID : false
But, for the same network when I try to get WIFI SSID using
onCapabilitiesChanged, it returns SSID: <unknown ssid> and
getHiddenSSID : true
注：提供地点许可。

Question 2


          
           花了几天时间，终于找到了我在
           
            onCapabilitiesChanged
           
           中得不到SSID的原因。
          
          
           在创建对象时，我们需要在
           
            FLAG_INCLUDE_LOCATION_INFO
           
           构造函数中传递
           
            ConnectivityManager.NetworkCallback
           
           。
          
          
           在默认构造函数中，位置敏感信息被隐藏了，因此我们无法在
           
            onCapabilitiesChanged
           
           中获得SSID。一旦我们创建了带有标志的
           
            NetworkCallback
           
           对象，我们就会得到SSID。

Question 3


          
           Get SSID and BSSID API31 Xamarin C# Example
          
          
           需要的权限。change_network_state, access_fine_location
          
          
           If API<31
           
            运输信息
           
           will return Null
          
          using Android.Content;
using Android.Net;
using Android.Net.Wifi;
protected override void OnStart()
        base.OnStart();
        NetworkRequest request = new NetworkRequest.Builder().AddTransportType(transportType: TransportType.Wifi).Build();
        ConnectivityManager connectivityManager = Android.App.Application.Context.GetSystemService(Context.ConnectivityService) as ConnectivityManager;
        NetworkCallbackFlags flagIncludeLocationInfo = NetworkCallbackFlags.IncludeLocationInfo;
        NetworkCallback networkCallback = new NetworkCallback((int)flagIncludeLocationInfo);
        connectivityManager.RequestNetwork(request, networkCallback);
    private class NetworkCallback : ConnectivityManager.NetworkCallback
        public NetworkCallback(int flags) : base(flags)
        public override void OnCapabilitiesChanged(Network network, NetworkCapabilities networkCapabilities)
            base.OnCapabilitiesChanged(network, networkCapabilities);
            WifiInfo wifiInfo = (WifiInfo)networkCapabilities.TransportInfo;
            if (wifiInfo != null)
                string ssid = wifiInfo.SSID.Trim(new char[] {'"', '\"' });
                string bssid = wifiInfo.BSSID;
Click Android API reference.ConnectivityManager.NetworkCallback(int)!

Question 4


          
           
            Replace from
            
             new NetworkCallback()
            
            to
            
             new NetworkCallback(ConnectivityManager.NetworkCallback.FLAG_INCLUDE_LOCATION_INFO)
            
            .
           
           
            
             示例代码。
            
           
           final NetworkRequest request =
      new NetworkRequest.Builder()
      .addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
      .build();
 final ConnectivityManager connectivityManager =
      context.getSystemService(ConnectivityManager.class);
 final NetworkCallback networkCallback = new NetworkCallback(ConnectivityManager.NetworkCallback.FLAG_INCLUDE_LOCATION_INFO) {
      @Override
      void onAvailable(Network network) {}
      @Override
      void onCapabilitiesChanged(Network network, NetworkCapabilities networkCapabilities) {
          WifiInfo wifiInfo = (WifiInfo) networkCapabilities.getTransportInfo();
      // etc.
 connectivityManager.requestNetwork(request, networkCallback); // For request