Nokia s 40 (Out of memory exception)

[hasharts]

HI,

In my game i have different classes which extends GameCanves for different screens( Help, About Us, Game ect). I move from screen to screen by making an object of that class and by setting it to the current display. This works well in sony ericsson phones and some Nokia phones like N 73, N 70 ect. But in Nokia 6300 , 6280 (s 40 series) it gives out of memory exception when I make an additional object.

ex- for main menu and game i call these methods in the main Midlet
MainMenu mm;
Game game;

showMainMenu() {
if(mm == null) {
mm = new MainMenu();
}
setCurrentDisplay(mm);
}

showGame() {
if(game == null) {
game = new MainMenu();
}
setCurrentDisplay(game);
}

when i call showGame() after calling showMainMenu() it gives out of memory exception.

Thanks,
Hashani

[DevelopmentTeam]

1) Don't use many gamecanvas extended classes in your program. Instead what we usually do is, we have an abstract class named screens. Each screen is designed to display each window (or menu). The game canvas calls the functions that is set to display and switching the screens must be much simpler.

Screen abstract class

Code: Select all

import javax.microedition.lcdui.Graphics;

public abstract class Screen {

    private byte keyState;

    public abstract void drawScreen(Graphics g);

    public abstract void GameCycle(long ticks);

    public abstract void GamePausedTime(long secs);

//    public abstract boolean canPause();

    public byte GetKeyState() {
        return KeyConstant.getGameCodeKey(keyState);
    }

    public void SetKeyState(byte key) {
        keyState = key;
    }
}


GameCanvas class

Code: Select all

package BeesFlowers;
import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Graphics;
public class GameCanvas extends Canvas implements Runnable {
    private Screen currentScreen;
    private static final long MS_PER_FRAME = 60; //  Hz
    private static final long MS_PER_FRAME1 = 90;
    private boolean paused = false;
    private boolean endGame = false;
    public static boolean running = true;
    private byte keyStates;
    private byte oldkey;
    private BeesFlowers midlet;
    private long pausedTime = 0;
    private long kp;
    public Thread thread;
    public GameCanvas(BeesFlowers midlet) {       
        this.midlet = midlet;
        setFullScreenMode(true);
        thread = new Thread(this);
        thread.start();       
    }
    public void SetScreen(Screen screen) {
        currentScreen = null;
        System.gc();
        currentScreen = screen;       
            }
    protected void paint(Graphics g) {
        g.setClip(0, 0, getWidth(), getHeight());
        g.setColor(255, 255, 255);
        g.fillRect(0, 0, getWidth(), getHeight());
        g.setClip(0, 0, Store.DisplayWidth, Store.DisplayHeight);
        if (currentScreen != null && !paused) {
            currentScreen.drawScreen(g);
        } else {
            g.setColor(0, 0, 0);
            g.fillRect(0, 0, Store.DisplayWidth, Store.DisplayHeight);
            g.setColor(255, 255, 255);
            g.drawString("Game Paused", 55, 100, 0);
        } 
        g.setColor(255, 255, 255);     
    }
    public void Quit() {
        midlet.Quit();
        this.endGame = true;
    }
    public void run() {
        long midTime;
        long delta = 0;
        try {
            midTime = System.currentTimeMillis();
            while (running) {
                //System.out.println("Used Memory : " + (Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory())/1024);
                if (endGame) {
                    return;
                }
                if (!paused) {
                    synchronized (this) {
                        if (currentScreen != null) {
                            currentScreen.SetKeyState(this.keyStates);
                            currentScreen.GameCycle(midTime);
                        }
                        delta = System.currentTimeMillis() - midTime;
                        midTime = System.currentTimeMillis();
                    }
                    if (Store.splashScreen != null) {
                        if (delta < MS_PER_FRAME1) {
                            synchronized (this) {
                                wait(MS_PER_FRAME1 - delta);
                            }
                        } else {
                            Thread.yield();
                        }
                    } else {
                        if (delta < MS_PER_FRAME) {
                            synchronized (this) {
                                wait(MS_PER_FRAME - delta);
                            }
                        } else {
                            Thread.yield();
                        }
                    }
                }
                repaint();
                serviceRepaints();
            }
        } catch (Exception e) {
        }
    }
    public void togglePause() {
//        if (!paused) {
//            pausedTime = System.currentTimeMillis();
//        } else {
//            currentScreen.GamePausedTime(System.currentTimeMillis() - pausedTime);
//        }
//        paused = !paused;
    }
   
    protected void keyPressed(int keyCode) {
        this.keyStates = (byte) keyCode;
        if (KeyConstant.getGameCodeKey(this.keyStates) == KeyConstant.KEY_POUND) {
            togglePause();
        }
    }
    protected void keyReleased(int keyCode) {
        Store.ReleasedKey = keyCode;
        this.keyStates = 0;
    }
    protected void keyRepeated(int keyCode) {
        Store.PressedKey = keyCode;
    }
}


2) Outofmemory is an error that pops when you run out of memory and it depends on the capacity of the handset. So you have to optimize each classes like free the memory in the old gamecanvas before constructing another.

[hasharts]

Hi CodeTiger,

Sorry for the late reply . Thank you very much for the details and the code. That was really useful for me.

Regards,
Hashani

[DevelopmentTeam]

Welcome...

[escapee626]

Wow, I actually found this pretty useful as well. Thanks to the both of you!