maincanvas.java

J2ME编程的50个例子,适合掌上系统的编程

package demo;
import CSMidlet;

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 int			m_nLife;						//生命值
	private MyRecord		m_Record;						//记录对象
	private MyBack			m_Back;							//背景对象
	private GunAndAim		m_GunAim;						//准心对象
	private EnemySprite	m_aEnemy[];						//敌人对象
	private Random			m_Random;
	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();
	}
	//重新开局
	private void Reset(){	
		//创建随机数对象
		if( m_Random == null )
			m_Random = new Random();
		//设置生命值
		m_nLife	= 10;
		//创建记录对象
		if( m_Record == null )
			m_Record = new MyRecord("CSScore");
		m_Record.setCurRecord(0);
		//创建背景
		if( m_Back == null )
			m_Back = new MyBack();
		//创建枪和准心图像
		if( m_GunAim == null )
			m_GunAim = new GunAndAim(getWidth(), getHeight());
		//创建敌人
		if( m_aEnemy == null ){
			try{
				Image img = Image.createImage("/demo/enemy.png");
				m_aEnemy = new EnemySprite[6];
				for( int n = 0; n < m_aEnemy.length; n ++ ){
					m_aEnemy[n] = new EnemySprite(img, 47, 45);
					m_aEnemy[n].setState(EnemySprite.ENEMY_HIDE);
				}
				int x = getWidth() / 2;
				int y = getHeight() / 2;
				//设置六个敌人的位置
				m_aEnemy[0].setPosition(x - 90, y - 80);
				m_aEnemy[1].setPosition(x - 19, y - 80);
				m_aEnemy[2].setPosition(x + 40, y - 80);
				m_aEnemy[3].setPosition(x - 90, y - 20);
				m_aEnemy[4].setPosition(x - 18,  y);
				m_aEnemy[5].setPosition(x + 40, y - 20);
			}
			catch(Exception exception){}
		}
		
        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
					CSMidlet.midlet.notifyDestroyed();
					break;
				}
			}
			break;			
		case GAME_GAMING:									//游戏中
			m_GunAim.Input(keyStates, getWidth(), getHeight() );
			//如果玩家开火，则将准心与敌人做碰撞检测
			if( m_GunAim.getState() == GunAndAim.GA_FIRE ){
				for( int n = 0; n < m_aEnemy.length; n ++ ){
					if( m_GunAim.m_AimSp.collidesWith( m_aEnemy[n], true ) )
					{//如果打中敌人，则增加分数
						int record = m_Record.getCurRecord();
						m_Record.setCurRecord(record + 1);
						m_aEnemy[n].setState(EnemySprite.ENEMY_DEAD);
						break;
					}
				}
			}
			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
					CSMidlet.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:
			m_GunAim.Logic();
			for( int n = 0; n < m_aEnemy.length; n ++ ){
				m_aEnemy[n].Logic();
				if(m_aEnemy[n].getState() == EnemySprite.ENEMY_FIRE)
				{//如果敌人开火，则减少生命值
					m_nLife --;
					if( m_nLife <= 0 )			//失去生命，游戏结束
						setState(GAME_END);
					break;
				}
			}
			CreateEnemy();
			break;
		}
	}
	public void Paint(){
		Graphics g = getGraphics();
		//用黑色清屏
		g.setColor(0);
		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:
			//显示敌人
			for( int n = 0; n < m_aEnemy.length; n ++ ){
				m_aEnemy[n].paint(g);
			}
			//显示背景
			m_Back.Paint(g, getWidth(), getHeight());
			//显示枪和准心
			m_GunAim.Paint(g);
			//显示生命值
			StringBuffer buff = new StringBuffer();
			buff.append("Life:");
			buff.append(m_nLife);
			g.drawString(buff.toString(), 5, 5, 0 );
			m_UI.Paint(g, getWidth(), getHeight());
			break;
		case GAME_END:
			m_Back.Paint(g, getWidth(), getHeight());
			m_Record.Paint(g, getWidth(), getHeight());
			break;
		}
		flushGraphics();
	}
	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;
			}
		}
	}
	//随机产生新敌人
	private void CreateEnemy(){
		int rs = Math.abs(m_Random.nextInt() % 20);
		if( rs >= 6 )
			return;
		if( m_aEnemy[rs].getState() == EnemySprite.ENEMY_HIDE )
			m_aEnemy[rs].setState(EnemySprite.ENEMY_NORMAL);
	}
}