maincanvas.java

J2ME手机游戏50例

package demo;
import java.util.Random;

import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.game.GameCanvas;

public class MainCanvas extends GameCanvas implements Runnable{
	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_END		= 2;	//游戏结束
	public static final int GAME_STATE_NUM = 3;	//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 MyBack			m_Back;					//游戏背景
	private MyUI			m_UI;					//用户界面	
	private ChickSprite	m_Chick;				//管理小鸡对象
	private GoodsSprite	m_Goods[];				//管理物品对象
	private int			m_nScore = 0;			//当前得分
	private int			m_nTime = 60 * 10;		//游戏总时间
	private Random			m_Random;
	public MainCanvas(){
		super(true);
		m_Random = new Random();
		m_Back = new MyBack();
		m_UI = new MyUI();
		try{
			//读取小鸡精灵图片,并设置小鸡的初始位置
			Image img = Image.createImage("/demo/chick.png");
			m_Chick = new ChickSprite( img, 31, 29 );
			m_Chick.setRefPixelPosition( getWidth() / 2, getHeight() - 18 );
			
			//读取物品图片,屏幕上最多同时掉落6个物品
			img = Image.createImage("/demo/goods.png");
			m_Goods = new GoodsSprite[6];
			for( int n = 0; n < m_Goods.length; n ++ )
				m_Goods[n] = new GoodsSprite( img, 19, 19 );
		}
		catch (Exception ex){} 
		setState(GAME_UI);							//设置游戏状态
		Start();									//启动线程
	}
	private void setState( int state ){			//设置当前的游戏状态
		if( state < 0 || state >= GAME_STATE_NUM )
			return;
		m_nState = state;
	}
	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() {							//新线程自动调用此方法
		//获取系统当前时间，并将时间换算成以毫秒为单位的数
		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(){							//终止游戏
		m_bRunning = false;
	}
	public void Input(){
		//根据不同的游戏状态，处理按键操作
		int keyStates = getKeyStates();
		switch( m_nState ){
		case GAME_UI:								//进入用户界面
			m_UI.Input( keyStates );
			if( m_UI.getState() == MyUI.UI_HIDE )	//当用户界面被隐藏时进入游戏
				setState(GAME_GAMING);
			break;
		case GAME_GAMING:							//进入游戏
			if( m_nTime <= 0 )						//如果游戏超时
				return;	
			m_Chick.Input( keyStates, getWidth(), getHeight() );
			break;
		}
	}
	public void Logic(){
		//根据不同的游戏状态，处理逻辑操作
		switch( m_nState ){
		case GAME_UI:								//进入用户界面
			break;
		case GAME_GAMING:							//进入游戏
			m_Chick.Logic();
			for( int n = 0; n < m_Goods.length; n ++ )
				m_Goods[n].Logic( getHeight() );
			Collides();								//碰撞检测
			CreateGoods();							//随机生成新物品
			m_nTime --;
			if( m_nTime <= 0 )						//如果游戏超时
				setState(GAME_END);
			break;
		}
	}
	private void Collides(){							//碰撞检测
		for( int n = 0; n < m_Goods.length; n ++ ){
			if( m_Chick.collidesWith( m_Goods[n], true ) )
			{//如果小鸡与物品发生碰撞,即小鸡接到了物品
				switch( m_Goods[n].getType() ){
				case GoodsSprite.GODDS_GOLD:			//接到金元宝
					m_nScore += 5;						//增加5个积分点
					break;
				case GoodsSprite.GODDS_DIAMOND:			//接到钻石
					m_nScore += 10;						//增加10个积分点
					break;
				case GoodsSprite.GODDS_FRUIT:			//接到圆形水果会被砸倒
					m_Chick.setState( ChickSprite.CHICK_DOWN );
					break;
				}
				m_Goods[n].setVisible(false);			//让物品消失
			}
		}
	}
	private void CreateGoods(){						//随机产生新物品
		//以1比20的概率产生新物品
		int rand = m_Random.nextInt() % 10;				//rand在-10~10之间
		if( rand != 0 )							
			return;
		for( int n = 0; n < m_Goods.length; n ++ ){
			if( m_Goods[n].isVisible() == false ){
				//随机设置新物品的种类及初始位置
				int type = Math.abs( m_Random.nextInt());
				type = type % GoodsSprite.GODDS_TYPE_NUM;
				m_Goods[n].setType(type);
				
				int x = m_Random.nextInt() % getWidth() - 10;
				x = Math.abs(x);
				m_Goods[n].StartDrop( x, 0 );
				break;
			}
		}
	}
	public void Paint(){
		Graphics g = getGraphics();
		//用黑色清屏
		g.setColor(0);
		g.fillRect(0, 0, getWidth(), getHeight());
		
		switch( m_nState ){
		case GAME_UI:									//显示标题界面
			m_UI.Paint(g, getWidth(), getHeight());
			break;
		case GAME_GAMING:								//显示游戏画面
			m_Back.Paint(g, getWidth(), getHeight());
			m_Chick.paint(g);
			for( int n = 0; n < m_Goods.length; n ++ )
				m_Goods[n].paint(g);
			//显示文字信息
			StringBuffer strText = new StringBuffer();
			strText.append("Time:");
			strText.append(m_nTime / 10);
			strText.append("     Score:");
			strText.append(m_nScore);
			g.drawString( strText.toString(), 5, 5, 0 );
			break;
		case GAME_END:									//显示结束信息
			m_Back.Paint(g, getWidth(), getHeight());
			StringBuffer strEndText = new StringBuffer();
			strEndText.append("游戏结束,本次得分:");
			strEndText.append(m_nScore);
			g.drawString( strEndText.toString(), 20, getHeight()/2, 0 );
			break;
		}
		flushGraphics();
	}
}