J2ME Canvas Example

This example illustrates how to create a game using GameCanvas class. In this example we are extending GameCanvas class to draw the circle and rotate the circle continuously.


 
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J2ME Canvas Example

     

A J2ME Game Canvas Example

This example illustrates how to create a game using GameCanvas class. In this example we are extending GameCanvas class to draw the circle and rotate the circle continuously. The GameCanvas class has following methods:

  • flushGraphics():- This is the void type method, it flushes to display on the off-screen buffer.
  • flushGraphics(int x, int y, int width, int height):- This is the void type method, it flushes to display of specified region on the off-screen buffer. 
  • getGraphics():- This is used to get the graphics objects.
  • getKeyStates():- This is the integer type variable, it is used to find the states of the key. 
  • paint(Graphics g):- This is also the void type method, it is used to paint the canvas. 

Other commands, input event, etc  methods inherited from Canvas class. The Canvas class has following methods:

  • getGameAction(int keyCode) 
  • getHeight()
  • getKeyCode(int gameAction) 
  • getKeyName(int keyCode)
  • getWidth()
  • hasPointerEvents()
  • hasPointerMotionEvents() 
  • hasRepeatEvents()
  • hideNotify() 
  • isDoubleBuffered()
  • keyPressed(int keyCode) 
  • keyReleased(int keyCode) 
  • keyRepeated(int keyCode) 
  • paint(Graphics g)
  • pointerDragged(int x, int y) 
  • pointerPressed(int x, int y) 
  • pointerReleased(int x, int y) 
  • repaint() 
  • repaint(int x, int y, int width, int height) 
  • serviceRepaints() 
  • showNotify()

 

Source Code of CanvasGame.java

import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.*;
import javax.microedition.midlet.*;

public class CanvasGame extends MIDlet{

  private Command back;
  private Display display;
  final SweepGame game = new SweepGame();

  public void startApp() {
  back = new Command("Back", Command.BACK, 0);
  game.start();
  game.addCommand(back);
  game.setCommandListener(new CommandListener(){
  public void commandAction(Command c, Displayable s) {
  game.stop();
  notifyDestroyed();
  }
  });
  display = Display.getDisplay(this);
  display.setCurrent(game);
  }

  public void pauseApp() {}

  public void destroyApp(boolean unconditional) {}
}

class SweepGame extends GameCanvas implements Runnable {
  private boolean move;
  private int radius;
  private int diameter;
  private int interval;

  public SweepGame() {
  super(true);
  radius = 0;
  diameter = 10;
  interval = 0;
  }
  public void start() {
  move = true;
  Thread t = new Thread(this);
  t.start();
  }
  public void stop() {
  move = false;
  }
  public void render(Graphics g) {
  int width = getWidth();
  int height = getHeight();
  g.setColor(183,251,121);
  g.fillRect(0, 0, width - 1, height - 1);
  int x = diameter;
  int y = diameter;
  int w = width - diameter * 2;
  int h = height - diameter * 2;
  for (int i = 0; i < 17; i=i+2) {
  g.setColor(((17 - i) * 15 - 7),20,((17 - i) * 15 - 7));
  g.fillArc(x, y, w, h, radius + i * 10, 10);
  g.fillArc(x, y, w, h, (radius + 180) % 360 + i * 10, 10);
  }
  }
  public void run() {
  Graphics g = getGraphics();
  while (move) {
  radius = (radius + 1) % 360;
  render(g);
  flushGraphics();
  try {
  Thread.sleep(interval);
  }
  catch (InterruptedException ie) {}
  }
  }
}

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J2ME Canvas Example

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Comments:2
Mochamad
September 14, 2011
nothing

it's cool
Imen
September 28, 2012
wLXVsuWstcN

Thanks for the quick reply. I can get it to output a pdf in this way, yes. I just wanetd to output more than one! If I save a png during the loop then I can reloop and save different versions, but I can't seem to do this with pdfs if that makes sense? Thanks again.

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