Implementing the MIDlet Main class

The Main class is the MIDlet main class. When the MIDlet is launched, the Main class is loaded first.

To implement the Main class:

1. Create the Main.java class file.

2. Import the required packages and classes.

   package com.nokia.example.imagescaler;
   
   import javax.microedition.lcdui.Alert;
   import javax.microedition.lcdui.Display;
   import javax.microedition.midlet.MIDlet;

3. Create the Main class to extend the MIDlet. The Main class owns the object of the MainView (UI class).

   public class Main extends MIDlet
   {
       private MainView mainView;
       private final boolean isAPIAvailable;

4. Create the Main class constructor.

   public Main() {
       // Checks whether the FileSelect API is available or not
       isAPIAvailable = System.getProperty("microedition.io.file.FileConnection.version") != null;
   }

5. Define the mandatory lifecycle methods for starting, pausing, and destroying the MIDlet.

   public void startApp() {
       if (isAPIAvailable) {
           mainView = new MainView("Image Scaler Example", this);
           Display.getDisplay(this).setCurrent(mainView);
       }
       else {
           String text = getAppProperty("MIDlet-Name") + "\n"
                         + getAppProperty("MIDlet-Vendor")
                         + "\nFile Connection API is not available!";
           Alert alert = new Alert(text);
           Display.getDisplay(this).setCurrent(alert);
       }
   }
   
   public void pauseApp() {
   }
   
   public void destroyApp(boolean unconditional) {
   }
   
   public void quit() {
       destroyApp(true);
       notifyDestroyed();
   }
   }