Tic-Tac-Toe Over Sockets port for Series 40 touch and type and full touch devices. This Nokia example demonstrates the use of datagrams for peer discovery and the use of TCP sockets for peer-to-peer communication.
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.
Application Descriptor


Tic-Tac-Toe over Sockets for Series 40

Tic-Tac-Toe Over Sockets port for Series 40 touch and type and full touch devices. This Nokia example demonstrates the use of datagrams for peer discovery and the use of TCP sockets for peer-to-peer communication.

This example application demonstrates:

  • The use of datagrams to implement automatic peer discovery
  • How to use TCP sockets for peer-to-peer communication
  • How to scale graphics for varying size of game board

This example application is hosted in GitHub:

1. Usage

To play with two devices, make sure that the devices are connected to the same wireless network and that the reception is good. Then launch the application and tap Start Two Player Game. The devices should discover each other. Once the connection is established, the game board is shown and the game begins.

Note that the discovery is not guaranteed to work in all networks. The automatic peer discovery works only with the condition that the wireless access point hands out IP addresses where the last digit varies. E.g. the discovery will work with devices that have IPs and, but not if the IPs are and

2. Project structure and implementation

2.1 Folders

Folder Description
root The root folder contains the project files, the Application Descriptor file, the license information and this README file
binaries Contains the installable binaries.
res Contains the application resources (e.g. graphics assets).
src Contains the application source code.

2.2 Important files and classes

Note that some files/classes are omitted from the following tree.

  • src/ com.nokia.example.tictactoe
Class Description
Main The MIDlet main class.
Splash The splash screen implementation.
  • com.nokia.example.tictactoe.connectivity
Class Description
Connection An abstract class defining a base for any connection.
ConnectionManager Provides the main API for managing the whole package. However, the individual connection classes can be used separately.
DiscoveryClient UDP client based peer discovery connection.
DiscoveryServer UDP server based peer discovery.
TcpClient TCP client socket connection.
TcpServer TCP server socket connection.
UdpClient UDP (datagram) client socket connection.
UdpServer UDP (datagram) server socket connection.
  • com.nokia.example.tictactoe.console
Class Description
Console Displays the log messages on the screen.
Log Container for log messages.
TextWrapper A utility class for wrapping text when drawn with Graphics.drawString().
  • com.nokia.example.tictactoe.engine
Class Description
AbstractGameManager An abstract base class for game managers.
BasicGameManager A game manager for single player game.
GameModel The game model which knows where everything is.
IGameModelListener An interface for game model listeners.
ITicTacToeAI An interface for any AI (articial intelligence) opponent implementation.
MinimaxAI A simple minimax algorithm based AI implementation.
NetworkGameManager A game manager for two player game.
  • com.nokia.example.tictactoe.ui
Class Description
AboutView The about/info view.
Button A custom button.
GameGrid The visualisation of the game board.
GameView The game view.
InfoLabel A custom text label with a background.
ITouchListener An interface for touch event listeners.
MainView The main (menu) view.
ProgressBar A custom progress bar.
SettingsView The settings view.
TextLabel A custom text label.
TimedProgressBar A progress bar with a timer.

2.3 Used J2ME and Nokia UI API classes

Note: Some, less meaningful packages and classes omitted.

  • java.io

    • InputStream
    • OutputStream
  • javax.microedition.io

    • Connector
    • Datagram
    • DatagramConnection
    • ServerSocketConnection
    • SocketConnection
  • javax.microedition.lcdui

    • Canvas
    • Display
    • Displayable
    • Font
    • Graphics
    • Image

3. Compatibility

Compatible with Series 40 touch and type and full touch phones. Developed with Nokia SDK 2.0 for Java.

3.1 Known issues

  • The game does not function well, if the reception of the wireless network is poor, and connectivity implementation is not generally very tolerant for network errors.
  • The automatic peer discovery feature is not guaranteed to work in all wireless networks; the implementation depends on the wireless access point to hand out IPs where only the last value in the IP varies.

4. Building, installing, and running the application

4.1 Preparations

Check that you have Nokia SDK 2.0 for Java (or equivalent SDK) and the latest Nokia Suite installed.

4.2 Packaging the application using Nokia SDK 2.0 for Java

You cannot install the application on the device with the IDE, but you can package the application: after you have imported the project, locate the Application Descriptor in the Package Explorer window and open it. Open the Overview tab (by default it is the first tab on the left) and click Create package. Select the destination directory and click Finish.

4.3 Installing application binary with Nokia Suite

Connect the phone to the computer with USB cable or Bluetooth. Locate the application binary (.jar file). Open the file using Nokia Suite. You can also drag the file from the file explorer on top of the connected phone image in the Nokia Suite window.

After the application is installed, locate the application icon from the application menu and launch the application by selecting the icon.

5. License

See the license text file delivered with this project. The license file is also available online at https://github.com/nokia-developer/tic-tac-toe-jme/blob/master/LICENCE.TXT

6. Version history

1.0 Initial release