Programming Tutorials

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Sample program to draw a rectangle in J2ME

By: Sam Chen in J2ME Tutorials on 2007年09月16日 [フレーム]

Here's a sample program to draw a rectangle in J2ME:

import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class RectangleMIDlet extends MIDlet implements CommandListener {
 private Display display;
 private Command exitCommand;
 private RectangleCanvas canvas;
 
 public RectangleMIDlet() {
 display = Display.getDisplay(this);
 exitCommand = new Command("Exit", Command.EXIT, 0);
 canvas = new RectangleCanvas();
 canvas.addCommand(exitCommand);
 canvas.setCommandListener(this);
 }
 public void startApp() {
 display.setCurrent(canvas);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 notifyDestroyed();
 }
 public void commandAction(Command c, Displayable d) {
 if (c == exitCommand) {
 destroyApp(true);
 }
 }
}
class RectangleCanvas extends Canvas {
 protected void paint(Graphics g) {
 int w = getWidth();
 int h = getHeight();
 g.setColor(0xffffff);
 g.fillRect(0, 0, w, h);
 g.setColor(0x000000);
 g.drawRect(10, 10, w - 20, h - 20);
 }
}

In this program, we create a RectangleMIDlet class that extends the MIDlet class. This class creates a RectangleCanvas object that extends the Canvas class. In the RectangleCanvas class, we override the paint() method to draw a rectangle using the Graphics class's drawRect() method. We also set the background color using the fillRect() method. Finally, we create a Command object to allow the user to exit the program.