1. Import the required classes and interfaces.

   import net.rim.blackberry.api.bbm.platform.*;
   import net.rim.blackberry.api.bbm.platform.service.*;
   import net.rim.device.api.ui.component.*;

2. Define a session listener. The code sample in step 5 assumes that you named the listener class, MySessionListener.
3. Create a class that extends MainScreen. In the constructor for this screen class, pass in the application's associated BBMPlatformContext object.

   public class MyBBMInviteScreen extends MainScreen
   {
       public MyBBMInviteScreen(BBMPlatformContext platformContext) 
       {
   
       }
   }

4. In the constructor, retrieve a reference to the messaging service associated with this application's platform context.

   public class MyBBMInviteScreen extends MainScreen
   {
       public MyBBMInviteScreen(BBMPlatformContext platformContext) 
       {
           MessagingService messagingService = platformContext.getMessagingService();
       }
   }

5. Invoke MessagingService.createSession() to create a new BBMPlatformSession instance. Pass in an instance of the listener, that you defined in step 2, as a parameter.

   public class MyBBMInviteScreen extends MainScreen
   {
       public MyBBMInviteScreen(BBMPlatformContext platformContext) 
       {
           MessagingService messagingService = platformContext.getMessagingService();
           BBMPlatformSession mySession = messagingService.createSession(new MySessionListener());
       }
   }

6. Invoke BBMPlatformSession.sendInvitation() to invite a contact to your session. The sendInvitation()method can take three parameters. The first parameter specifies a message to be delivered when the contact receives the invitation. The second parameter is an argument that will be passed to the application's main method as args[1]. The third parameteris the invitation's expiry time. The following code sample passes in the value 0 for expiry time (that is, the invitation never expires). A Contact picker UI component will automatically open for the user to choose a contact to invite.

   public class MyBBMInviteScreen extends MainScreen
   {
       public MyBBMInviteScreen(BBMPlatformContext platformContext) 
       {
           MessagingService messagingService = platformContext.getMessagingService();
           BBMPlatforSession mySession = messagingService.createSession(new MySessionListener());
   
           if (mySession != null) 
           {
               mySession.sendInvitation(“Let's play a game”, "Poker App", 0);
           }
           
       }
   }

Code sample: Sending a session join invitation to a contact

import net.rim.blackberry.api.bbm.platform.*;
import net.rim.blackberry.api.bbm.platform.service.*;
import net.rim.device.api.ui.component.*;

public class MyBBMSessionScreen extends MainScreen
{
    public MyBBMSessionScreen(BBMPlatformContext platformContext)
    {
        MessagingService messagingService = platformContext.getMessagingService();
        BBMPlatforSession mySession = messagingService.createSession(new MySessionListener());

        if (mySession != null) 
        {
            mySession.sendInvitation(“Let's play a game”, "Poker App", 0);
        }
    }
}