SignalR integration in android studio

Question

I use signalR lib in my project. but I was not able to compile libs of https://github.com/SignalR/java-client on my own - I found them in internet. But it seems like there are not full (WebsocketTransport is missing)

When I compile https://github.com/SignalR/java-client, i get two libs, and paste them to my app.gradle -

compile files ('libs/signalr-client-sdk.jar')
compile files ('libs/signalr-client-sdk-android.jar')

Progects build suckesfully, butwhen I press run - it fails. Here is stack trace -

  UNEXPECTED TOP-LEVEL EXCEPTION:
com.android.dx.cf.iface.ParseException: bad class file magic (cafebabe) or version (0034.0000)
at com.android.dx.cf.direct.DirectClassFile.parse0(DirectClassFile.java:472)
at com.android.dx.cf.direct.DirectClassFile.parse(DirectClassFile.java:406)
at com.android.dx.cf.direct.DirectClassFile.parseToInterfacesIfNecessary(DirectClassFile.java:388)
at com.android.dx.cf.direct.DirectClassFile.getMagic(DirectClassFile.java:251)
at com.android.dx.command.dexer.Main.processClass(Main.java:704)
at com.android.dx.command.dexer.Main.processFileBytes(Main.java:673)
at com.android.dx.command.dexer.Main.access$300(Main.java:83)
at com.android.dx.command.dexer.Main$1.processFileBytes(Main.java:602)
at com.android.dx.cf.direct.ClassPathOpener.processArchive(ClassPathOpener.java:284)
at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:166)
at com.android.dx.cf.direct.ClassPathOpener.process(ClassPathOpener.java:144)
at com.android.dx.command.dexer.Main.processOne(Main.java:632)
at com.android.dx.command.dexer.Main.processAllFiles(Main.java:510)
at com.android.dx.command.dexer.Main.runMonoDex(Main.java:280)
at com.android.dx.command.dexer.Main.run(Main.java:246)
at com.android.dx.command.dexer.Main.main(Main.java:215)
at com.android.dx.command.Main.main(Main.java:106)
...while parsing microsoft/aspnet/signalr/client/Action.class

1 error; aborting Error:Execution failed for task ':app:preDexDebug'.

com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command 'C:\Program Files\Java\jdk1.8.0_45\bin\java.exe'' finished with non-zero exit value 1

I do not know what to do. I even tried to compile forks of this project, but have got the same result, same error. Need any help, Thanks!

UPDATE

in my Application class i have

Platform.loadPlatformComponent(new AndroidPlatformComponent());

in my app.gradle:

compile files ('libs/gson-2.2.2.jar')
compile files ('libs/signalr-client-sdk.jar')
compile files ('libs/signalr-client-sdk-android.jar')

in my code I use

connection.start(new ServerSentEventsTransport(connection.getLogger())).get();

I also create lots of hubs on this connection, nad call methods. All works, but connection always dissapears, if i do not do anything with device more then for 30 seconds. And I do not have any callbacks that the connection was lost\disconected or anything like that - I log all this stuff. But I think it can happen because i have pretty old libs, i googled - as I mention in this question i did not menaged to build signalR project to receive more recent libs

Answer 1

Here is my working basic code, hope this helps!

package com.example.simplesignalrclient;

import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.Handler;
import android.os.IBinder;
import android.os.Looper;
import android.util.Log;
import android.widget.Toast;

import java.util.concurrent.ExecutionException;

import microsoft.aspnet.signalr.client.Credentials;
import microsoft.aspnet.signalr.client.Platform;
import microsoft.aspnet.signalr.client.SignalRFuture;
import microsoft.aspnet.signalr.client.http.Request;
import microsoft.aspnet.signalr.client.http.android.AndroidPlatformComponent;
import microsoft.aspnet.signalr.client.hubs.HubConnection;
import microsoft.aspnet.signalr.client.hubs.HubProxy;
import microsoft.aspnet.signalr.client.hubs.SubscriptionHandler1;
import microsoft.aspnet.signalr.client.transport.ClientTransport;
import microsoft.aspnet.signalr.client.transport.ServerSentEventsTransport;

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;
}