Use Canvas to draw a clock : Canvas « J2ME « Java Tutorial

1. Java Tutorial
2. J2ME
3. Canvas

import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Graphics;
import javax.microedition.midlet.MIDlet;

public class ClockMIDlet extends MIDlet implements CommandListener {

  private Command exitCommand;

  Display display;

  public void startApp() {
    Display display = Display.getDisplay(this);
    Displayable d = new ClockCanvas(10, 10, 10);
    exitCommand = new Command("Exit", Command.EXIT, 1);

    d.addCommand(exitCommand);
    d.setCommandListener(this);

    display.setCurrent(d);
  }

  public void pauseApp() {
  }

  public void destroyApp(boolean unconditional) {
  }

  public void commandAction(Command c, Displayable s) {
    notifyDestroyed();
  }
}

class ClockCanvas extends Canvas {

  private int hour;

  private int minute;

  private int second;

  protected int xCenter, yCenter;

  protected int clockRadius;

  int width = 0;

  int height = 0;

  ClockCanvas(int hour, int minute, int second) {
    this.hour = hour;
    this.minute = minute;
    this.second = second;
  }

  public void paint(Graphics g) {
    width = getWidth();
    height = getHeight();

    g.setGrayScale(255);
    g.fillRect(0, 0, width - 1, height - 1);
    g.setGrayScale(0);
    g.drawRect(0, 0, width - 1, height - 1);

    clockRadius = Math.min(width, height) - 20;

    xCenter = getWidth() / 2;
    yCenter = getHeight() / 2;

    g.drawArc(10, 12, clockRadius, clockRadius, 0, 360);

    g.drawString("12", xCenter, 0, Graphics.TOP | Graphics.HCENTER);
    g.drawString("9", 1, yCenter, Graphics.BASELINE | Graphics.LEFT);
    g.drawString("3", width - 1, yCenter, Graphics.BASELINE | Graphics.RIGHT);
    g.drawString("6", xCenter, height, Graphics.BOTTOM | Graphics.RIGHT);

  }
}

31.24.Canvas
	31.24.1.	extends Canvas to create your own drawable area
	31.24.2.	Get Canvas properties
	31.24.3.	Canvas key pressed and key typed events
	31.24.4.	Use Canvas to draw a clock
	31.24.5.	Canvas size
	31.24.6.	Navigatable Canvas
	31.24.7.	Canvas key event and navigate through arrow keys