Mobile Gameand Application withJ2ME

อ.เจนโชค เตชะโกเมนท์� (เจ)jenchoke@hotmail.comสาขาวิ�ชาส��อนฤม�ตคณะสารสนเท์ศศาสตร�มหาวิ�ท์ยาลั�ยมหาสารคามhttp://www.it.msu.ac.th/nmd

Canvas Canvas ม� method ส�าหร�บ handle game

action, key event น��นค�อเราสามารถเข�ยนโปรแกรมให%ร�บร& %การกดป()มบนม�อถ�อได% โดยใช% Canvas

นอกจากน�+น Canvas ย�งสามารถ regist CommandListener ได%เหม�อนก�บ Displayable อ��นๆ

แต. ท์��ส�าค�ญค�อ Canvas เป0น abstract class ด�งน�+น เราต%องสร%าง class อ��นๆให% extends Canvas เช.น

class MyCanvas extends Canvasแลั%วิจากน�+นจ1งสร%าง object MyCanvas เพื่��อน�าไปวิางบน Screen

Canvas

public class HelloCanvasMIDlet extends MIDlet {Display display;HelloCanvas canvas;public HelloCanvasMIDlet() {

canvas = new HelloCanvas();}protected void destroyApp(boolean arg0) {}

protected void pauseApp() {}

protected void startApp() throws MIDletStateChangeException {display = Display.getDisplay(this);display.setCurrent(canvas);canvas.repaint();

}}

class HelloCanvas extends Canvas{protected void paint(Graphics g) {

g.setColor(255, 0, 0); g.fillRect(0, 0, getWidth(), getHeight()); g.setColor(255, 255, 255);

g.drawString("HelloCanvasWorld", 5, 5,Graphics.TOP | Graphics.LEFT);}

}

class HelloCanvas extends Canvas{

protected void paint(Graphics g) {

g.setColor(255, 0, 0);

g.fillRect(0, 0, getWidth(), getHeight());

g.setColor(255, 255, 255);

g.drawString("HelloCanvasWorld", 5, 5,

Graphics.TOP | Graphics.LEFT);

}

}

import java.io.IOException;import javax.microedition.midlet.*;import javax.microedition.lcdui.*;public class GameActionExample extends MIDlet{ private Display display; private MyCanvas canvas; public GameActionExample() { display = Display.getDisplay(this); canvas = new MyCanvas (this); } protected void startApp() { display.setCurrent(canvas); } protected void pauseApp() { } protected void destroyApp( boolean unconditional ) { } public void exitMIDlet() { destroyApp(true); notifyDestroyed(); }}

GameActionExample.java

class MyCanvas extends Canvas implements CommandListener{ private Command exit; private String message; private GameActionExample gameActionExample; private int x, y; public MyCanvas (GameActionExample gameActionExample) { x = 5; y = 5; message = "Use Game Keys"; this.gameActionExample = gameActionExample; exit = new Command("Exit", Command.EXIT, 1); addCommand(exit); setCommandListener(this); } protected void paint(Graphics graphics) {

Image img = null;graphics.setColor(255,255,255);

graphics.fillRect(0, 0, getWidth(), getHeight()); graphics.setColor(255, 0, 0); try {

img = Image.createImage("/images/0.png");} catch (IOException e) {

e.printStackTrace();}

graphics.drawImage(img, x, y, Graphics.TOP | Graphics.LEFT); graphics.drawString(message, x + 10, y +50, Graphics.TOP | Graphics.LEFT); }

GameActionExample.java

public void commandAction(Command command, Displayable displayable)

{ if (command == exit) { gameActionExample.exitMIDlet(); } }

protected void keyPressed(int key) { switch ( getGameAction(key) ){ case Canvas.UP: message = "up"; y--; break; case Canvas.DOWN: message = "down"; y++; break; case Canvas.LEFT: message = "left"; x--; break; case Canvas.RIGHT: message = "right"; x++; break; case Canvas.FIRE: message = "FIRE"; break; } repaint(); }}

// A canvas that illustrates rectanglesclass RectanglesCanvas extends Canvas { public void paint(Graphics g) { int width = getWidth(); int height = getHeight();

// Create a white background g.setColor(0xffffff); g.fillRect(0, 0, width, height); // Draw a solid rectangle g.setColor(0); g.drawRect(width/4, 0, width/2, height/4); // Draw a dotted rectangle inside // the solid rectangle. g.setStrokeStyle(Graphics.DOTTED); g.drawRect(width/4 + 4, 4, width/2 - 8, height/4 - 8); // Draw a rounded rectangle g.setStrokeStyle(Graphics.SOLID); g.drawRoundRect(width/4, height/2, width/2, height/4, 16, 8); }}

// A canvas that illustrates filled rectanglesclass RectangleFillsCanvas extends Canvas { public void paint(Graphics g) { int width = getWidth(); int height = getHeight();

// Create a black background g.setColor(0); g.fillRect(0, 0, width, height);

// Draw a filled rectangle with // a dotted rectangle around it g.setStrokeStyle(Graphics.DOTTED); g.setColor(0x00ff00); g.fillRect(width/4, height/4, width/2, height/2); g.setColor(0xffff00); g.drawRect(width/4, height/4, width/2, height/2); }}

// A canvas that illustrates arcsclass ArcsCanvas extends Canvas { public void paint(Graphics g) { int width = getWidth(); int height = getHeight();

// Create a black background g.setColor(0); g.fillRect(0, 0, width, height);

g.setColor(0xffffff); g.drawArc(0, 0, width/2, height/2, 0, 90); g.setStrokeStyle(Graphics.DOTTED); g.setColor(0xffff00); g.drawRect(0, 0, width/2, height/2);

g.setStrokeStyle(Graphics.SOLID); g.setColor(0xffffff); g.drawArc(width/2, 0, width/2, height/2, 0, -90); g.setStrokeStyle(Graphics.DOTTED); g.setColor(0xffff00); g.drawRect(width/2, 0, width/2, height/2); }}

End of AM

การสร�างภาพบน Canvas ให้�เคลื่��อนไห้วด้�วย Thread

ในการเข�ยน application ต.างๆ โดยเฉพื่าะเกมส� Thread (เธรด) จ�ดเป0น Class ท์��ส�าค�ญมากใน

การควิบค(มการเคร��อนไหวิ อย.างอ�สระของ Image/Picture ใน game ให%ตรงก�บท์��เราต%อง

นอกจากน�+ย�งสามารถควิบค(ม input / output แลัะอ��นๆ อ�กด%วิย เก�อบท์�+งหมดของจาวิาเกมส�จะใช%

Class Thread น�+เป0นหลั�กในการ Control ฉะน�+นเราจ�าเป0นต%องท์�าควิามเข%าใจในเร��องของ Thread

อย.างลั1กซึ้1+งเพื่��อจะสามารภน�าไปใช%งานได%อย.างช�านาญ Method ห้ลื่�กๆของ Thread ประกอบด้�วย

Start() เป0นการส��งให% thread เร��มท์�างาน Sleep() เป0นการส��งให%พื่�กงานเป0นจ�งหวิะ Run() เป0นการควิบค(มการท์�างานของ thread

thread [N ] ; เร��องหร�อเหต(การณ�ท์��เก�ดข1+นต.อเน��องก�น

Thread

สร�างภาพ Animation บน Canvasimport javax.microedition.lcdui.*;

import javax.microedition.midlet.MIDlet;

public class SimpleGameMIDlet extends MIDlet implements CommandListener {

private Display mDisplay; private SimpleGameCanvas mCanvas; private Command mExitCommand;

public void startApp() { if (mCanvas == null) { mCanvas = new SimpleGameCanvas(); mCanvas.start(); mExitCommand = new Command("Exit", Command.EXIT, 0); mCanvas.addCommand(mExitCommand); mCanvas.setCommandListener(this); } mDisplay = Display.getDisplay(this); mDisplay.setCurrent(mCanvas); }

SimpleGameMIDlet.java

public void pauseApp() {} public void destroyApp(boolean unconditional) { mCanvas.stop(); } public void commandAction(Command c, Displayable s) { if (c.getCommandType() == Command.EXIT) { destroyApp(true); notifyDestroyed(); } }

public void pauseApp() {} public void destroyApp(boolean unconditional) { mCanvas.stop(); } public void commandAction(Command c, Displayable s) { if (c.getCommandType() == Command.EXIT) { destroyApp(true); notifyDestroyed(); } }

SimpleGameMIDlet.java

SimpleGameCanvas.java

import java.util.Timer;import javax.microedition.lcdui.*;import javax.microedition.lcdui.game.*;

public class SimpleGameCanvas extends GameCanvas implements Runnable { private volatile boolean mTrucking; private long mFrameDelay; private int mX, mY; int color_r = 255,color_g = 255,color_b = 255; private int mState; Timer timer = new Timer(); Timer tm; Image img;

import java.util.Timer;import javax.microedition.lcdui.*;import javax.microedition.lcdui.game.*;

public class SimpleGameCanvas extends GameCanvas implements Runnable { private volatile boolean mTrucking; private long mFrameDelay; private int mX, mY; int color_r = 255,color_g = 255,color_b = 255; private int mState; Timer timer = new Timer(); Timer tm; Image img;

public SimpleGameCanvas() { super(true); mX = getWidth() / 2; mY = getHeight() / 2; mState = 0; mFrameDelay = 20; }public void start() { mTrucking = true; Thread t = new Thread(this); t.start(); PrimeThread p = new PrimeThread(143); p.start(); }public void stop() { mTrucking = false; }public void run() { Graphics g = getGraphics(); while (mTrucking == true) { tick(); input(); render(g); try { Thread.sleep(mFrameDelay); } catch (InterruptedException ie) { stop(); } } }

public SimpleGameCanvas() { super(true); mX = getWidth() / 2; mY = getHeight() / 2; mState = 0; mFrameDelay = 20; }public void start() { mTrucking = true; Thread t = new Thread(this); t.start(); PrimeThread p = new PrimeThread(143); p.start(); }public void stop() { mTrucking = false; }public void run() { Graphics g = getGraphics(); while (mTrucking == true) { tick(); input(); render(g); try { Thread.sleep(mFrameDelay); } catch (InterruptedException ie) { stop(); } } }

SimpleGameCanvas.java

private void tick() { mState = (mState + 1) % 20; } private void input() { int keyStates = getKeyStates(); if ((keyStates & LEFT_PRESSED) != 0) mX = Math.max (0, mX - 1); if ((keyStates & RIGHT_PRESSED) != 0) mX = Math.min (getWidth(), mX + 1); if ((keyStates & UP_PRESSED) != 0) mY = Math.max (0, mY - 1); if ((keyStates & DOWN_PRESSED) != 0) mY = Math.min (getHeight(), mY + 1); } private void render(Graphics g) {

/* background color */g.setColor(255,255,255);

g.fillRect(0, 0, getWidth(), getHeight()); g.setColor(0,0,255); /* X point */ g.drawLine(mX, mY, mX - 10 + mState, mY - 10); g.drawLine(mX, mY, mX + 10, mY - 10 + mState); g.drawLine(mX, mY, mX + 10 - mState, mY + 10); g.drawLine(mX, mY, mX - 10, mY + 10 - mState);

flushGraphics(); }

private void tick() { mState = (mState + 1) % 20; } private void input() { int keyStates = getKeyStates(); if ((keyStates & LEFT_PRESSED) != 0) mX = Math.max (0, mX - 1); if ((keyStates & RIGHT_PRESSED) != 0) mX = Math.min (getWidth(), mX + 1); if ((keyStates & UP_PRESSED) != 0) mY = Math.max (0, mY - 1); if ((keyStates & DOWN_PRESSED) != 0) mY = Math.min (getHeight(), mY + 1); } private void render(Graphics g) {

/* background color */g.setColor(255,255,255);

g.fillRect(0, 0, getWidth(), getHeight()); g.setColor(0,0,255); /* X point */ g.drawLine(mX, mY, mX - 10 + mState, mY - 10); g.drawLine(mX, mY, mX + 10, mY - 10 + mState); g.drawLine(mX, mY, mX + 10 - mState, mY + 10); g.drawLine(mX, mY, mX - 10, mY + 10 - mState);

flushGraphics(); }

SimpleGameCanvas.java

class PrimeThread extends Thread { long minPrime; PrimeThread(long minPrime) { this.minPrime = minPrime; } public void run() { while (true) { try { System.out.println(System.currentTimeMillis()); sleep(1000); } catch (InterruptedException e) { } } } }

class PrimeThread extends Thread { long minPrime; PrimeThread(long minPrime) { this.minPrime = minPrime; } public void run() { while (true) { try { System.out.println(System.currentTimeMillis()); sleep(1000); } catch (InterruptedException e) { } } } }

SimpleGameCanvas.java

การทำ�างานของ TimerTaskข%อด�ของการใช% TimerTask ค�อใช%งานง.ายเพื่ราะม�

เมธอดให%ใช%งาน เพื่�ยงส��งให%เร��มต%นท์�างานด%วิยเมธอด run() แลัะหย(ดการท์�างานด%วิยเมธอด cancel()

การท์�างานของ TimerTask ต%องอาศ�ยการควิบค(มผ่.านเมธอด schedule() ของ class Timer อ�กท์�หน1�ง

timer = new Timer(); // ก�าหนด Instance ของ TimerTimerTask task = new TimerTask(Value); // สร%าง class ในส.วินการท์�างานในร&ปแบบของของ

// TimerTask

timer. Schedule(task,0,500); // timer จะควิบค(มการท์�างานของ TimerTask ท์�างานท์(กๆ

0.5 วิ�นาท์�

การทำ�างานของ TimerTaskTime.schedule()Time.schedule() TimerTask.run

(display)

TimerTask.run(display)

Paintrandom line

Paintrandom line

Main Time Task Display

ควิบค(ม ท์�าหน%าท์��ตามค�าส��ง

มี ว!ธี การเข ยน code j2me แบบง$ายด้�งน %คร�บ โด้ยเร!�มีเข ยนจาก

Java Classextends Canvas

Java Classextends Canvas

Java Classextends TimerTask

Java Classextends TimerTask

J2ME MidletClass

J2ME MidletClass

TimerTask

TimerTask

Class TimerDemoextends MIDlet

Class FieldMoverextends TimerTask

Class StarFieldextends Canvas

import javax.microedition.midlet.*;import javax.microedition.lcdui.*;import java.util.*;

import javax.microedition.midlet.*;import javax.microedition.lcdui.*;import java.util.*;

public class TimerDemo extends MIDlet { Display display; StarField field = new StarField(); FieldMover mover = new FieldMover(); Timer timer = new Timer(); public TimerDemo() { display = Display.getDisplay( this ); } protected void destroyApp( boolean unconditional ) { } protected void startApp() { display.setCurrent( field ); timer.schedule( mover, 0, 50 ); } protected void pauseApp() { } public void exit(){ timer.cancel(); // stop scrolling destroyApp( true ); notifyDestroyed(); }

TimerDemo.java

class FieldMover extends TimerTask { public void run() { field.scroll(); }}

class StarField extends Canvas { int height; int width; int[] stars; Random generator = new Random(); boolean painting = false; private Random genColor = new Random(); public StarField(){ height = getHeight(); width = getWidth(); stars = new int[ height ]; for( int i = 0; i < height; ++i ){ stars[i] = -1; } }

TimerDemo.java

public void scroll() { if( painting ) return; for( int i = height-1; i > 0; --i ){ stars[i] = stars[i-1]; } stars[0] = ( generator.nextInt() % ( 3 * width ) ) / 2; if( stars[0] >= width ){ stars[0] = -1; } repaint(); } protected void paint( Graphics g ){ painting = true; int r_color = genColor.nextInt(255); int g_color = genColor.nextInt(255); int b_color = genColor.nextInt(255); g.setColor( 0, 0, 0 ); g.fillRect( 0, 0, width, height ); g.setColor( r_color, g_color, b_color ); for( int y = 0; y < height; ++y ){ int x = stars[y]; if( x == -1 ) continue; g.drawLine( x, y, x, y ); } painting = false; }

TimerDemo.java

protected void keyPressed( int keyCode ){ exit(); } }}

protected void keyPressed( int keyCode ){ exit(); } }}

TimerDemo.java