Implementing the MIDlet main class

To implement the MIDlet main class:

1. Create the TouristMIDlet.java class file.

2. Assign the class to the com.nokia.example.location.tourist package.

   package com.nokia.example.location.touristroute;

3. Import the required classes.

   import javax.microedition.lcdui.Display;
   import javax.microedition.midlet.MIDlet;
   import javax.microedition.midlet.MIDletStateChangeException;
   
   import com.nokia.example.location.touristroute.model.ConfigurationProvider;
   import com.nokia.example.location.touristroute.model.ProviderStatusListener;
   import com.nokia.example.location.touristroute.model.TouristData;
   import com.nokia.example.location.touristroute.ui.MessageUI;
   import com.nokia.example.location.touristroute.ui.TouristUI;

4. Set TouristMIDlet to extend MIDlet and implement ProviderStatusListener. Create the required variables and the class constructor.

   public class TouristMIDlet extends MIDlet implements ProviderStatusListener
   {
       /** A static reference to Display object. */
       private static Display display = null;
   
       /** A Reference to TouristData. */
       private TouristData data = null;
   
       /** Lock object */
       private Object mutex = new Object();
   
       public TouristMIDlet()
       {
           super();
       }

5. Create the mandatory MIDlet lifecycle methods.

       protected void startApp() throws MIDletStateChangeException
       {
           display = Display.getDisplay(this);
   
           if (ConfigurationProvider.isLocationApiSupported())
           {
               ConfigurationProvider.getInstance().autoSearch(this);
           }
           else
           {
               MessageUI.showApiNotSupported();
           }
       }
   
       protected void pauseApp()
       {
       }
   
       protected void destroyApp(boolean unconditional)
               throws MIDletStateChangeException
       {
       }

6. Create a method for getting a reference to the Display object.

       /**
        * Getter method for Display reference.
        *
        * @return reference to Display object.
        */
       public static Display getDisplay()
       {
           return display;
       }

7. Create a method for indicating the selection of the location provider.

       /**
        * Event indicating location provider is selected. MIDlet use may therefore
        * begin.
        *
        * @see com.nokia.example.location.tourist.model.ProviderSelectedListener#providerSelectedEvent()
        */
       public void providerSelectedEvent()
       {
           // Attempt to acquire the mutex
           synchronized (mutex)
           {
               // Start scanning location updates. Also set the TouristData
               // reference data.
               MessageUI.showLocationProviderState();
   
               // Inform the user that MIDlet is looking for location data.
               data = new TouristData((ProviderStatusListener) this);
           }
       }

8. Create a method for indicating that the first location update has occurred.

       /**
        * Event indication about the first location update. This method sets
        * Tourist UI visible. By using mutex object, we ensure TouristaData (data)
        * is created on providerSelectedEvent.
        *
        * @see com.nokia.example.location.tourist.model.ProviderStatusListener#firstLocationUpdateEvent()
        */
       public void firstLocationUpdateEvent()
       {
           // Attempt to acquire the mutex
           synchronized (mutex)
           {
               TouristUI ui = new TouristUI(data);
   
               data.setTouristUI(ui);
               display.setCurrent(ui);
           }
       }
   }

Now that you have implemented the MIDlet main class, implement the location services.