How to use signalr in Android

Question

I am trying to integrate signalR in android app but no luck. I've been looking at various links but none of them provide proper information about implementation.

I've the following questions.

• SignalR integration has to be done inside Service/Intent Service?
• If we want to receive response via same calling method then how to get?

I've added three libraries i.e signalr android,signalr client and gson but unable to understand how code works, no proper documentation is available to understand the code.

Some of the questions asked but not much information

SignalR in Android Studio Unable to implement p2p chat using SignalR in Android

If anyone experienced in signal for native apps, it would be very helpful for me.

Update

    public class SignalRService extends Service {       private static final String TAG = "Service";     private HubConnection mHubConnection;     private HubProxy mHubProxy;     private Handler mHandler; // to display Toast message     private final IBinder mBinder = new LocalBinder();       private SharedPreferences sp;      @Override     public void onCreate() {         super.onCreate();          Utility.showLog(TAG, "Service Created");          sp = getSharedPreferences(Utility.SHARED_PREFS, MODE_PRIVATE);         mHandler = new Handler(Looper.myLooper());     }      @Override     public int onStartCommand(Intent intent, int flags, int startId) {          int result = super.onStartCommand(intent, flags, startId);         startSignalR();         return result;     }      @Override     public IBinder onBind(Intent intent) {          startSignalR();         return mBinder;     }      /**      * Class used for the client Binder.  Because we know this service always      * runs in the same process as its clients, we don't need to deal with IPC.      */     public class LocalBinder extends Binder {         public SignalRService getService() {             // Return this instance of SignalRService so clients can call public methods             return SignalRService.this;         }     }      /**      * method for clients (activities)      */     public void sendMessage() {          String SERVER_METHOD_SEND = "iAmAvailable";         final String string = new String();          mHubProxy.invoke(new String(), SERVER_METHOD_SEND, sp.getString("user_id", null), sp.getString("pass", null), "TransMedic").done(new Action() {             @Override             public void run(Object o) throws Exception {                  Utility.showLog(TAG, o.toString());              }           }).onError(new ErrorCallback() {             @Override             public void onError(Throwable throwable) {              }         });     }      private void startSignalR() {          Platform.loadPlatformComponent(new AndroidPlatformComponent());          String serverUrl = "http://transit.alwaysaware.org/signalr";          mHubConnection = new HubConnection(serverUrl);          String SERVER_HUB_CHAT = "ChatHub";          mHubProxy = mHubConnection.createHubProxy(SERVER_HUB_CHAT);          ClientTransport clientTransport = new ServerSentEventsTransport(mHubConnection.getLogger());          SignalRFuture<Void> signalRFuture = mHubConnection.start(clientTransport);           try {              signalRFuture.get();          } catch (InterruptedException | ExecutionException e) {              e.printStackTrace();             return;          }          sendMessage();     }      @Override     public void onDestroy() {          mHubConnection.stop();         super.onDestroy();      } } 

Answer 1

UPDATE 2018:

If you are using SignalR.net Core use this library otherwise you will get error on connection.

SERVER SIDE:

The following is my sample server-side code, you can pay attention to public void Send(string message) and public void SendChatMessage(string to, string message).

• Server-side app: public void SendChatMessage(string to, string message)

  • Android client app: mHubProxy.invoke("SendChatMessage", receiverName, message);

• Server-side app: public void Send(string message)

  • Android client app: mHubProxy.invoke("Send", message);

namespace SignalRDemo {     public class ChatHub : Hub     {         private static ConcurrentDictionary<string, string> FromUsers = new ConcurrentDictionary<string, string>();         // <connectionId, userName>         private static ConcurrentDictionary<string, string> ToUsers = new ConcurrentDictionary<string, string>();           // <userName, connectionId>         private string userName = "";      public override Task OnConnected()     {         DoConnect();         Clients.AllExcept(Context.ConnectionId).broadcastMessage(new ChatMessage() { UserName = userName, Message = "I'm Online" });         return base.OnConnected();     }      public override Task OnDisconnected(bool stopCalled)     {         if (stopCalled) // Client explicitly closed the connection         {             string id = Context.ConnectionId;             FromUsers.TryRemove(id, out userName);             ToUsers.TryRemove(userName, out id);             Clients.AllExcept(Context.ConnectionId).broadcastMessage(new ChatMessage() { UserName = userName, Message = "I'm Offline" });         }         else // Client timed out         {             // Do nothing here...             // FromUsers.TryGetValue(Context.ConnectionId, out userName);                         // Clients.AllExcept(Context.ConnectionId).broadcastMessage(new ChatMessage() { UserName = userName, Message = "I'm Offline By TimeOut"});                         }          return base.OnDisconnected(stopCalled);     }      public override Task OnReconnected()     {         DoConnect();         Clients.AllExcept(Context.ConnectionId).broadcastMessage(new ChatMessage() { UserName = userName, Message = "I'm Online Again" });         return base.OnReconnected();     }      private void DoConnect()     {         userName = Context.Request.Headers["User-Name"];         if (userName == null || userName.Length == 0)         {             userName = Context.QueryString["User-Name"]; // for javascript clients         }         FromUsers.TryAdd(Context.ConnectionId, userName);         String oldId; // for case: disconnected from Client         ToUsers.TryRemove(userName, out oldId);         ToUsers.TryAdd(userName, Context.ConnectionId);     }      public void Send(string message)     {         // Call the broadcastMessage method to update clients.                     string fromUser;         FromUsers.TryGetValue(Context.ConnectionId, out fromUser);         Clients.AllExcept(Context.ConnectionId).broadcastMessage(new ChatMessage() { UserName = fromUser, Message = message });     }      public void SendChatMessage(string to, string message)     {         FromUsers.TryGetValue(Context.ConnectionId, out userName);         string receiver_ConnectionId;         ToUsers.TryGetValue(to, out receiver_ConnectionId);          if (receiver_ConnectionId != null && receiver_ConnectionId.Length > 0)         {             Clients.Client(receiver_ConnectionId).broadcastMessage(new ChatMessage() { UserName = userName, Message = message });         }     }         }  public class ChatMessage {     public string UserName { get; set; }     public string Message { get; set; } } } 

CLIENT SIDE:

If you have not read my answer at the following question:

SignalR integration in android studio

Then, here is my working basic code:

public class SignalRService extends Service {     private HubConnection mHubConnection;     private HubProxy mHubProxy;     private Handler mHandler; // to display Toast message     private final IBinder mBinder = new LocalBinder(); // Binder given to clients  public SignalRService() { }  @Override public void onCreate() {     super.onCreate();     mHandler = new Handler(Looper.getMainLooper()); }  @Override public int onStartCommand(Intent intent, int flags, int startId) {     int result = super.onStartCommand(intent, flags, startId);     startSignalR();     return result; }  @Override public void onDestroy() {     mHubConnection.stop();     super.onDestroy(); }  @Override public IBinder onBind(Intent intent) {     // Return the communication channel to the service.     startSignalR();     return mBinder; }  /**  * Class used for the client Binder.  Because we know this service always  * runs in the same process as its clients, we don't need to deal with IPC.  */ public class LocalBinder extends Binder {     public SignalRService getService() {         // Return this instance of SignalRService so clients can call public methods         return SignalRService.this;     } }  /**  * method for clients (activities)  */ public void sendMessage(String message) {     String SERVER_METHOD_SEND = "Send";     mHubProxy.invoke(SERVER_METHOD_SEND, message); }      private void startSignalR() {     Platform.loadPlatformComponent(new AndroidPlatformComponent());      Credentials credentials = new Credentials() {         @Override         public void prepareRequest(Request request) {             request.addHeader("User-Name", "BNK");         }     };      String serverUrl = "http://192.168.1.100";     mHubConnection = new HubConnection(serverUrl);     mHubConnection.setCredentials(credentials);     String SERVER_HUB_CHAT = "ChatHub";     mHubProxy = mHubConnection.createHubProxy(SERVER_HUB_CHAT);     ClientTransport clientTransport = new ServerSentEventsTransport(mHubConnection.getLogger());     SignalRFuture<Void> signalRFuture = mHubConnection.start(clientTransport);      try {         signalRFuture.get();     } catch (InterruptedException | ExecutionException e) {         e.printStackTrace();         return;     }      String HELLO_MSG = "Hello from Android!";     sendMessage(HELLO_MSG);      String CLIENT_METHOD_BROADAST_MESSAGE = "broadcastMessage";     mHubProxy.on(CLIENT_METHOD_BROADAST_MESSAGE,             new SubscriptionHandler1<CustomMessage>() {                 @Override                 public void run(final CustomMessage msg) {                     final String finalMsg = msg.UserName + " says " + msg.Message;                     // display Toast message                     mHandler.post(new Runnable() {                         @Override                         public void run() {                             Toast.makeText(getApplicationContext(), finalMsg, Toast.LENGTH_SHORT).show();                         }                     });                 }             }             , CustomMessage.class); } } 

Activity:

public class MainActivity extends AppCompatActivity {  private final Context mContext = this; private SignalRService mService; private boolean mBound = false;  @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main);      Intent intent = new Intent();     intent.setClass(mContext, SignalRService.class);     bindService(intent, mConnection, Context.BIND_AUTO_CREATE); }  @Override protected void onStop() {     // Unbind from the service     if (mBound) {         unbindService(mConnection);         mBound = false;     }     super.onStop(); }      public void sendMessage(View view) {     if (mBound) {         // Call a method from the SignalRService.         // However, if this call were something that might hang, then this request should         // occur in a separate thread to avoid slowing down the activity performance.         EditText editText = (EditText) findViewById(R.id.edit_message);                     if (editText != null && editText.getText().length() > 0) {                             String message = editText.getText().toString();             mService.sendMessage(message);         }     } }  /**  * Defines callbacks for service binding, passed to bindService()  */ private final ServiceConnection mConnection = new ServiceConnection() {      @Override     public void onServiceConnected(ComponentName className,                                    IBinder service) {         // We've bound to SignalRService, cast the IBinder and get SignalRService instance         SignalRService.LocalBinder binder = (SignalRService.LocalBinder) service;         mService = binder.getService();         mBound = true;     }      @Override     public void onServiceDisconnected(ComponentName arg0) {         mBound = false;     } }; } 

CustomMessage Class:

public class CustomMessage {     public String UserName;     public String Message; } 

You can also see my sample client project at this GitHub link

---

UPDATE FOR RESPONSE FROM INVOKE:

I have just added new sample methods:

Server side:

public string iAmAvailable(string username, string password, string message) {                  return "BNK Response for testing Android INVOKE"; } 

Client side:

mHubProxy.invoke(String.class, "iAmAvailable", "username", "password", "TransMedic").done(new Action<String>() {             @Override             public void run(String s) throws Exception {                 Log.w("SimpleSignalR", s);             }         }).onError(new ErrorCallback() {             @Override             public void onError(Throwable throwable) {                 Log.e("SimpleSignalR", throwable.toString());             }         }); 

And here is the screenshot: