Java Tutorial/J2ME/Timer

Alarm with Timer and Alert

import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
import javax.microedition.lcdui.Alert;
import javax.microedition.lcdui.AlertType;
import javax.microedition.lcdui.rumand;
import javax.microedition.lcdui.rumandListener;
import javax.microedition.lcdui.DateField;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.Item;
import javax.microedition.lcdui.ItemStateListener;
import javax.microedition.midlet.MIDlet;
public class AlarmMIDlet extends MIDlet implements ItemStateListener, CommandListener {
  private Command alarmCommand= new Command("alarm", Command.SCREEN, 1);
  private Command resetCommand= new Command("Reset", Command.SCREEN, 1);
  private Command exitCommand= new Command("Exit", Command.EXIT, 1);
  private Display display;
  private DateField alarmTimeSetting;
  private Form aForm= new Form("Alarm Setting");
  private int dateIndex;
  private Date currentTime= new Date();
  private Timer aTimer;
  private boolean dateOK = false;
  public AlarmMIDlet() {
    display = Display.getDisplay(this);
    alarmTimeSetting = new DateField("", DateField.DATE_TIME);
    alarmTimeSetting.setDate(currentTime);
    dateIndex = aForm.append(alarmTimeSetting);
    aForm.addCommand(alarmCommand);
    aForm.addCommand(resetCommand);
    aForm.addCommand(exitCommand);
    aForm.setCommandListener(this);
    aForm.setItemStateListener(this);
  }
  public void startApp() {
    display.setCurrent(aForm);
  }
  public void pauseApp() {
  }
  public void destroyApp(boolean unconditional) {
  }
  public void itemStateChanged(Item item) {
    if (item == alarmTimeSetting) {
      if (alarmTimeSetting.getDate().getTime() < currentTime.getTime())
        dateOK = false;
      else
        dateOK = true;
    }
  }
  public void commandAction(Command c, Displayable s) {
    if (c == alarmCommand) {
      if (dateOK == false) {
        Alert aAlert = new Alert("Cannot set", "Warning", null, null);
        aAlert.setTimeout(Alert.FOREVER);
        aAlert.setType(AlertType.ERROR);
        display.setCurrent(aAlert);
      } else {
        aTimer = new Timer();
        alarmTimerTask aTimerTask = new alarmTimerTask();
        long amount = alarmTimeSetting.getDate().getTime() - currentTime.getTime();
        aTimer.schedule(aTimerTask, amount);
        aForm.removeCommand(alarmCommand);
        aForm.removeCommand(resetCommand);
        aForm.delete(dateIndex);
        aForm.setTitle("Waiting....");
      }
    } else if (c == resetCommand) {
      alarmTimeSetting.setDate(currentTime = new Date());
    } else if (c == exitCommand) {
      destroyApp(false);
      notifyDestroyed();
    }
  }
  class alarmTimerTask extends TimerTask {
    public final void run() {
      Alert aAlert = new Alert("Alert!");
      aAlert.setTimeout(Alert.FOREVER);
      aAlert.setType(AlertType.ALARM);
      AlertType.ERROR.playSound(display);
      display.setCurrent(aAlert);
      cancel();
    }
  }
}

Fixed Rate Schedule MIDlet

import java.util.Calendar;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
import javax.microedition.lcdui.rumand;
import javax.microedition.lcdui.rumandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.TextBox;
import javax.microedition.midlet.MIDlet;
public class FixedRateScheduleMIDlet extends MIDlet implements CommandListener {
  private Command exitCommand = new Command("Exit", Command.EXIT, 1);
  private Display display;
  TextBox t= new TextBox("Time setting", "", 256, 0);
  private Timer aTimer= new Timer();
  private Date currentTime= new Date();
  private Calendar now = Calendar.getInstance();
  public FixedRateScheduleMIDlet() {
    display = Display.getDisplay(this);
    now.setTime(currentTime);
  }
  public void startApp() {
    ClockTimerTask aTimerTask = new ClockTimerTask();
    aTimer.schedule(aTimerTask, 1000, 1000);
    t.addCommand(exitCommand);
    t.setCommandListener(this);
    display.setCurrent(t);
  }
  public void pauseApp() {
  }
  public void destroyApp(boolean unconditional) {
  }
  public void commandAction(Command c, Displayable s) {
    if (c == exitCommand) {
      destroyApp(false);
      notifyDestroyed();
    }
  }
  class ClockTimerTask extends TimerTask {
    public final void run() {
      t.setString("" + now.get(Calendar.HOUR) + ":" + now.get(Calendar.MINUTE) + ":"
          + now.get(Calendar.SECOND) + ":");
      display.setCurrent(t);
    }
  }
}

Simple Timer

import java.util.Timer;
import java.util.TimerTask;
import javax.microedition.lcdui.rumand;
import javax.microedition.lcdui.rumandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.TextBox;
import javax.microedition.midlet.MIDlet;
public class SimpleTimerMIDlet extends MIDlet implements CommandListener {
  private Command exitCommand = new Command("Exit", Command.EXIT, 1);
  private Command scheduleCommand = new Command("schedule", Command.SCREEN, 1);
  private TextBox aTextBox = new TextBox("Setting", "Content", 20, 0);
  public static String aMessage = "";
  Display display;
  private Timer aTimer;
  private SimpleTimerTask aTimerTask;
  public SimpleTimerMIDlet() {
    display = Display.getDisplay(this);
  }
  public void startApp() {
    aTextBox.addCommand(exitCommand);
    aTextBox.addCommand(scheduleCommand);
    aTextBox.setCommandListener(this);
    display.setCurrent(aTextBox);
  }
  public void pauseApp() {
  }
  public void destroyApp(boolean unconditional) {
  }
  public void commandAction(Command c, Displayable s) {
    if (c == scheduleCommand) {
      aTimer = new Timer();
      aTimerTask = new SimpleTimerTask();
      aTimer.schedule(aTimerTask, 500);
      aTextBox.setString(aMessage);
    } else if (c == exitCommand) {
      destroyApp(false);
      notifyDestroyed();
    }
  }
}
class SimpleTimerTask extends TimerTask {
  public final void run() {
    System.out.println("Executing ....");
    cancel();
  }
}