maincanvas.java

J2ME编程的50个例子,适合掌上系统的编程

package demo;
import TrizoneMidlet;

import java.util.Random;

import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.game.GameCanvas;


public class MainCanvas extends GameCanvas 
				implements Runnable, CommandListener{
	public static final int GAME_UI				= 0;	//进入用户界面
	public static final int GAME_GAMING			= 1;	//进行游戏
	public static final int GAME_BUTTON			= 2;	//游戏时显示界面按钮
	public static final int GAME_END				= 3;	//游戏结束
	public static final int GAME_STATE_NUM 		= 4;	//状态总数
	private int m_nState	= GAME_UI;						//存储当前的游戏状态
	
	private boolean		m_bRunning;			    		//控制线程运行
	private MyUI			m_UI;							//界面对象
	private ManSprite 		m_Man;							//英雄对象
	private EnemySprite	m_Enemy;						//敌人对象
	private MyBack			m_Back;							//场景对象
	private Random			m_Random;						//随机数对象
	private Command MenuCommand;							//高级按钮对象
	public MainCanvas( ){
		super(true);			
		try{
			//创建用户界面，并设置界面中的按钮
			MyButton button = new MyButton(41, 21, 0, 1, -1, -1, -1, 2);
			m_UI = new MyUI(button);
        }
        catch(Exception exception){}
        setState(GAME_UI);
		Start();
	}
	//重新开牌
	private void Reset(){	
		//创建随机数对象
		if( m_Random == null )
			m_Random = new Random();
		//创建背景
		if( m_Back == null )
			m_Back = new MyBack();
		//创建英雄
		if( m_Man == null ){
			try{
				Image img = Image.createImage("/demo/man.png");
				m_Man = new ManSprite(img, 43, 47);
			}
			catch(Exception e){}
		}
		//创建敌人
		if( m_Enemy == null ){
			try{
				Image img = Image.createImage("/demo/enemy.png");
				m_Enemy = new EnemySprite(img, 35, 47 );
			}
			catch(Exception e){}
		}
		m_Man.setPosition( 50, 80 );
		
        if( MenuCommand == null ){
        	//创建菜单
        	MenuCommand = new Command("Menu", Command.OK, 0);
        	addCommand(MenuCommand);
            setCommandListener(this);
        }        
	}
	private void setState( int state ){					//设置游戏状态
		if( state < 0 || state >= GAME_STATE_NUM )
			return;
		m_nState = state;
		switch( m_nState ){
		case GAME_UI:										//进入用户界面
			m_UI.setState(MyUI.UI_TITLE);					//显示标题界面
			//设置本游戏的按钮类型，本游戏有:开始及退出两种按钮
			m_UI.getButton().setShow(true, false, false, false, false, true );
			break;
		case GAME_BUTTON:									//在游戏中途显示按钮
			m_UI.setState(MyUI.UI_BUTTON);
			//游戏中途，显示复位与退出按钮
			m_UI.getButton().setShow(false, true, false, false, false, true );
			break;
		case GAME_GAMING:									//正在游戏
			m_UI.setState(MyUI.UI_HIDE);
			break;
		case GAME_END:										//游戏结束
			m_UI.setState(MyUI.UI_HIDE);
			break;;
		}
	}
	public void Start(){
		m_bRunning = true;
		Thread thread = new Thread(this);	//分配新线程
		thread.start();						//线程启动
	}
	public void run() {
		//得到系统当前时间,并将时间换算成毫秒
		long T1 = System.currentTimeMillis();
		long T2 = T1;
		while(m_bRunning){
			T2 = System.currentTimeMillis();
			if( T2 - T1 > 100 ){			//间隔100毫秒
				T1 = T2;
				Input();
				Logic();
				Paint();
			}
		}
	}
	public void Stop(){
		m_bRunning = false;
	}
	public void Input(){
		int keyStates = getKeyStates();
		switch( m_nState ){
		case GAME_UI:
			{
				switch( m_UI.Input( keyStates ) ){
				case MyButton.BUTTON_START:					//按下开始键
					Reset();
					setState(GAME_GAMING);
					break;
				case MyButton.BUTTON_EXIT:					//按下退出键
					TrizoneMidlet.midlet.notifyDestroyed();
					break;
				}
			}
			break;			
		case GAME_GAMING:									//游戏中
			m_Man.Input(keyStates, getWidth(), getHeight());
			break;
		case GAME_BUTTON:									//游戏中途显示按钮
			{
				switch( m_UI.Input( keyStates ) ){
				case MyButton.BUTTON_RESET:					//按下复位键
					Reset();
					setState(GAME_GAMING);
					break;
				case MyButton.BUTTON_EXIT:					//按下退出键
					TrizoneMidlet.midlet.notifyDestroyed();
					break;
				}
			}
			break;
		case GAME_END:
			if( ( keyStates & GameCanvas.FIRE_PRESSED ) != 0 ){
				Reset();
				setState(GAME_GAMING);
			}
			break;
		}
	}
	public void Logic(){	
		switch( m_nState ){
		case GAME_GAMING:
			//碰撞检测
		    CheckCollision();
			//英雄逻辑
			m_Man.Logic();
			//敌人逻辑
		    m_Enemy.Logic();
		    
		    CreateEnemy();
			break;
		}
	}
	public void Paint(){
		Graphics g = getGraphics();
		//清屏
		g.setColor(0xFF008800);
		g.fillRect( 0, 0, getWidth(), getHeight() );
		
		g.setColor(0xFFFF0000);
		switch( m_nState ){
		case GAME_UI:								//显示界面
			m_UI.Paint(g, getWidth(), getHeight());
			break;			
		case GAME_GAMING:							//显示游戏画面
		case GAME_BUTTON:
		case GAME_END:
			m_Back.Paint(g, getWidth(), getHeight());
			//根据英雄与敌人的位置关系，调整显示顺序
			if( m_Man.getY() + m_Man.getHeight() > m_Enemy.getY() + m_Enemy.getHeight() ){
				m_Enemy.paint(g);
				m_Man.paint(g);
			}
			else{
				m_Man.paint(g);
				m_Enemy.paint(g);
			}
			m_UI.Paint(g, getWidth(), getHeight());
			break;
		}
		flushGraphics();
	}
	//碰撞检测
	private void CheckCollision()
	{
		switch( m_Man.m_nState ){
		case ManSprite.MAN_ATTACK:
			if( m_Man.collidesWith( m_Enemy, true) ){
				m_Enemy.BeHit(m_Man.getRefPixelX(), getWidth());
			}
			break;
		}
	}
	//随机产生敌人
	public void CreateEnemy() {
		if( m_Enemy.isVisible() )
	    	return;
	    int x = m_Random.nextInt() % (getWidth() - 30);
	    x = Math.abs(x) + 30;
	    int y = m_Random.nextInt() % (getHeight()-60);
	    y = Math.abs(y) + 60;	    	
	    m_Enemy.Start(x, y);
	}
	public void commandAction(Command c, Displayable s){
		if( c == MenuCommand ){
			switch( m_nState ){	
			case GAME_END:							//游戏结束，显示按钮
			case GAME_GAMING:						//正在游戏，显示按钮	
				setState(GAME_BUTTON);
				break;
			case GAME_BUTTON:						//正显示按钮，退回游戏
				setState(GAME_GAMING);
				break;
			default:
				break;
			}
		}
	}
}