Question

Well, I am writing an android application and I want to use Socket.IO-Client for Java written by Gottox. The documentation in github specifically say the library is compatible with android.

Now my question is somewhat basic. How to use that library in an android app?

So far I have tried two method.

1. I built a jar file of that library using the commands (as explained
   in the library’s doc)

   cd $PATH_TO_SOCKETIO_JAVA
   ant jar
   ls jar/socketio.jar
   

   I got a nice jar library in the folder. I added that jar to my
   project using

   RIGHT_CLICK->Properties->Java Build Path->Add External Jars
   

   Then I connected using

   SocketIO socket = new SocketIO("http://"+ip+":"+port+"/");
   

   I was able to compile and build my app without any errors. But when I run I got an exception on the line I have posted above.

   java.lang.NoClassDefFoundError: io.socket.SocketIO
       at com.research.socketioresearch.LoginActivity.connectToSocketIO(LoginActivity.java:122)
       at com.research.socketioresearch.LoginActivity$1.handleMessage(LoginActivity.java:113)
   

2. As a second try, I created a java project using the socket.io
   library source code in my eclipse. Then I exported that project as a
   jar file using

   RIGHT_CLICK->export->java->Jar File
   

   Then I added that jar file to my original android project using the
   same way I tried in method 1 (Add external jars). This time also I was able to
   compile and build, but getting the same exception at same line of
   code.

Now anyone has success in using the same library in android? How it is done?

Answer 1

Well I got it working myself..

1. Use the first method I mentioned in the question, you will get a jar
   file in the path

   PATH_TO_SOCKETIO_JAVA/jar/socket.jar
   

2. Now in your android project, create a folder called “libs” (if it is
   not already there)
3. Copy that jar file to the ‘libs’ folder.
4. Go to eclipse and refresh the android project.

I am still not sure why adding jar file using “Add external Jars ” button in project properties is not working. Both add library to the project right?