maincanvas.java

J2ME编程的50个例子,适合掌上系统的编程

package demo;
import javax.microedition.lcdui.Font;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.game.GameCanvas;

public class MainCanvas extends GameCanvas implements Runnable{
	private boolean	m_bRunning;				//控制项目运行
	public int m_nPosY;						//控制文字位置的纵坐标
	public Font m_aFont[];						//Font类的数组，存储多种字体
	public MainCanvas(){
		super(true);
		//变量初始画
		m_nPosY 	= 0;
		m_aFont 	= new Font[5];				//分配数组大小
		//存储各种字体，如果创建新字体失败，则存储系统默认字体
		try{
			m_aFont[0] 	= Font.getFont(Font.FACE_SYSTEM, 
							Font.STYLE_BOLD, Font.SIZE_MEDIUM);
		}catch(Exception e){
			m_aFont[0]  = Font.getDefaultFont();
		}
		try{
			m_aFont[1] 	= Font.getFont(Font.FACE_PROPORTIONAL, 
							Font.STYLE_UNDERLINED|Font.STYLE_BOLD, 
							Font.SIZE_SMALL);
		}catch(Exception e){
			m_aFont[1]  = Font.getDefaultFont();
		}
		try{
			m_aFont[2] 	= Font.getFont(Font.FACE_SYSTEM, 
							Font.STYLE_ITALIC, Font.SIZE_MEDIUM);
		}catch(Exception e){
			m_aFont[2]  = Font.getDefaultFont();
		}
		try{
			m_aFont[3] 	= Font.getFont(Font.FACE_SYSTEM, 
							Font.STYLE_UNDERLINED, Font.SIZE_SMALL);
		}catch(Exception e){
			m_aFont[3]  = Font.getDefaultFont();
		}
		try{
			m_aFont[4] 	= Font.getFont(Font.FACE_PROPORTIONAL, 
							Font.STYLE_PLAIN, Font.SIZE_LARGE);
		}catch(Exception e){
			m_aFont[4]  = Font.getDefaultFont();
		}
		
		Start();								//启动线程
	}
	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
		//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(){						//终止游戏
		m_bRunning = false;
	}
	public void Input(){
	}
	public void Logic(){
		//不断更改m_nPosY的值，实现文字滚屏
		m_nPosY ++;	
		//如果文字已滚至屏幕最下方，则重新设置文字的纵坐标
		if( m_nPosY > getHeight() )
			m_nPosY = 0;
	}
	public void Paint(){
		Graphics g = getGraphics();
		//用黑色清屏
		g.setColor(0x00000000);
		g.fillRect( 0, 0, getWidth(), getHeight() );
		g.setColor(0x00ffff00);
		//设置当前字体，并以不同字体输出“2008年奥运会”几个字
		g.setFont(m_aFont[0]);
		g.drawString( "2008年奥运会", 20, m_nPosY - 40, 0 );
		g.setFont(m_aFont[1]);
		g.drawString( "2008年奥运会", 50, m_nPosY - 25, 0 );
		g.setFont(m_aFont[2]);
		g.drawString( "2008年奥运会", 80, m_nPosY, 0 );
		g.setFont(m_aFont[3]);
		g.drawString( "2008年奥运会", 90, m_nPosY + 26, 0 );
		g.setFont(m_aFont[4]);
		g.drawString( "2008年奥运会", 40, m_nPosY + 42, 0 );
		flushGraphics();
	}
}