hello.java

大量j2me源代码

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

/**
 * A simple example that demonstrates the basic structure of a MIDlet
 * by creating a Form object containing the string "Hello, Micro World!"
 * @author Martin J. Wells
 */
public class Hello extends javax.microedition.midlet.MIDlet
       implements CommandListener
{
   protected Form form;
   protected Command quit;

   /**
    * Constructor for the MIDlet which instantiates the Form object and
    * then adds a text message. It then sets up a command listener so it
    * will get called back when the user hits the quit command. Note that this
    * Form is not activated (displayed) until the startApp method is called.
    */
   public Hello()
   {
      // create a form and add our components
      form = new Form("My Midlet");
      form.append("Hello, Micro World!");

      // create a way to quit
      form.setCommandListener(this);
      quit = new Command("Quit", Command.SCREEN, 1);
      form.addCommand(quit);
   }

   /**
    * Called by the Application Manager when the MIDlet is starting or resuming
    * after being paused. In this example it acquires the current Display object
    * and uses it to set the Form object created in the MIDlet constructor as
    * the active Screen to display.
    * @throws MIDletStateChangeException
    */
   protected void startApp() throws MIDletStateChangeException
   {
      // display our form
      Display.getDisplay(this).setCurrent(form);
   }

   /**
    * Called by the MID's Application Manager to pause the MIDlet. A good
    * example of this is when the user receives an incoming phone call whilst
    * playing your game. When they're done the Application Manager will call
    * startApp to resume. For this example we don't need to do anything.
    */
   protected void pauseApp()
   {
   }

   /**
    * Called by the MID's Application Manager when the MIDlet is about to
    * be destroyed (removed from memory). You should take this as an opportunity
    * to clear up any resources and save the game. For this example we don't
    * need to do anything.
    * @param unconditional if false you have the option of throwing a
    * MIDletStateChangeException to abort the destruction process.
    * @throws MIDletStateChangeException
    */
   protected void destroyApp(boolean unconditional)
           throws MIDletStateChangeException
   {
   }

   /**
    * The CommandListener interface method called when the user executes a
    * Command, in this case it can only be the quit command we created in the
    * consutructor and added to the Form.
    * @param command the command that was triggered
    * @param displayable the displayable on which the event occurred
    */
   public void commandAction(Command command, Displayable displayable)
   {
      // check for our quit command and act accordingly
      try
      {
         if (command == quit)
         {
            destroyApp(true);

            // tell the Application Manager we're exiting
            notifyDestroyed();
         }
      }

      // we catch this even though there's no chance it will be thrown
      // since we called destroyApp with unconditional set to true.
      catch (MIDletStateChangeException me)
      { }
   }
}