linecanvas.java

在手机上实现画线功能

import javax.microedition.lcdui.*;

public class LineCanvas
    extends Canvas implements CommandListener{
    	
    	
    	public static LineDemo ld;
    	public Command back;
    	public LineCanvas(LineDemo a){
    		ld=a;
    		back = new Command("返回", Command.BACK, 0);
    		addCommand(back);
    		setCommandListener(this);
    	}
    	public void commandAction(Command c, Displayable d){
      	if(c==back){
      		ld.show(ld.f);
      	}
      }
    	public void paint(Graphics g){
    		g.setColor(0, 0, 0);
        g.fillRect(0, 0,this.getWidth(),this.getHeight());
        g.setColor(255, 255, 255); 
        for(int i=0;i<4;i++){
        g.drawLine(ld.x[i],ld.y[i],ld.x[i+1],ld.y[i+1]);	
        }
    	}
    }