colortest.java

java手机程序开发随书光盘源代码

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class ColorTest extends MIDlet implements CommandListener, ItemStateListener{

	Display display;
	Form form;
	Gauge red, green, blue;
	MyCanvas myCanvas;
	Command exitCmd;
	Command okCmd;

	public ColorTest(){
		display = Display.getDisplay(this);
		form = new Form("设定颜色");
		red = new Gauge("Red:0", true, 255, 0);
		green = new Gauge("Green:0", true, 255, 0);
		blue = new Gauge("Blue:0", true, 255, 0);
		myCanvas = new MyCanvas(form);
		exitCmd = new Command("退出", Command.EXIT, 1);
		okCmd = new Command("确定", Command.OK, 1);
		form.append(red);
		form.append(green);
		form.append(blue);
		form.addCommand(exitCmd);
		form.addCommand(okCmd);
		form.setCommandListener(this);
		form.setItemStateListener(this);

	}


	public void startApp(){
		display.setCurrent(form);

	}

	public void pauseApp(){

	}

	public void destroyApp(boolean unconditional){

	}

	public void commandAction(Command c, Displayable d){
		if(c == exitCmd){
			destroyApp(true);
			notifyDestroyed();
		}
		else if(c == okCmd){
			int r = (red.getValue() & 0xff);
			int g = (green.getValue() & 0xff);
			int b = (blue.getValue() & 0xff);
			myCanvas.rgb = (r << 16)| (g << 8) | b;
			display.setCurrent(myCanvas);
		}
	}

	public void itemStateChanged(Item item){

		if(item == red){
			red.setLabel("Red:"+red.getValue());
		}
		else if(item == green){
			green.setLabel("Green:"+green.getValue());
		}
		else if(item == blue){
			blue.setLabel("Blue:"+blue.getValue());
		}

	}

	class MyCanvas extends Canvas implements CommandListener{

		int rgb;
		Displayable previousScreen;
		Command backCmd;

		public MyCanvas(Displayable d){
			previousScreen = d;
			rgb =0;
			backCmd = new Command("返回", Command.BACK, 1);
			addCommand(backCmd);
			setCommandListener(this);
		}

		public void paint(Graphics g){

			g.setColor(rgb);
			g.fillRect(0, 0, getWidth(), getHeight());

		}

		public void commandAction(Command c, Displayable d){
			if(c == backCmd){
				display.setCurrent(previousScreen);
			}
		}
	}

}