Step 2: LocationMidlet.java

Begin with the class LocationMidlet and the method startApp. These add the UI to the displayed form. The UI displays the current locations, satellite data, and zoom level.

1. Add the following function to LocationMidlet.java:

   public void startApp() { form = new Form("LocationMIDlet"); testCommand = new Command("Test", Command.OK, 1); gmCommand = new Command("Google Maps", Command.OK, 3); exitCommand = new Command("Exit", Command.EXIT, 1); form.addCommand(testCommand); form.addCommand(gmCommand); form.addCommand(exitCommand); form.setCommandListener(this); latitudeString = new StringItem("Latitude:", "0"); form.append(latitudeString); longitudeString = new StringItem("Longitude:", "0"); form.append(longitudeString); zoomGauge = new Gauge("Zoom level", true, 17, 12); form.append(zoomGauge); Display.getDisplay(this).setCurrent(form); }

   Select All

2. Add the ability to get the current location. These values are saved to the attributes latitude and longitude and are displayed on the screen.

   Add the following functions to LocationMidlet.java:

   public void run() { askLocation(); } private void askLocation() { form.append("\nWait, getting location..."); try { // Create a Criteria object for defining desired selection criteria Criteria cr = new Criteria(); // Specify horizontal accuracy of 500 meters, leave other parameters at default values. cr.setHorizontalAccuracy(500); LocationProvider lp = LocationProvider.getInstance(cr); // get the location, five minutes timeout Location l = lp.getLocation(300); Coordinates c = l.getQualifiedCoordinates(); if (c != null) { latitude = c.getLatitude(); longitude = c.getLongitude(); latitudeString.setText(""+latitude); longitudeString.setText(""+longitude); System.out.println("latitude: " + latitude); System.out.println("longitude: " + longitude); } } catch (LocationException le) { // not able to retrive location information form.delete(form.size()-1); form.append("\nLocationException: " + le.getMessage()); } catch (InterruptedException ie) { form.delete(form.size()-1); form.append("\nInterruptedException: " + ie.getMessage()); } form.delete(form.size()-1); }

   Select All

3. Add the implementation to handle actions of commands. TestCommand starts a new thread and returns the new locations. gmCommand displays a map at the current location if the location is known.

   Add the following function to LocationMidlet.java:.

   public void commandAction (Command c, Displayable d) { if (c == testCommand) { thread = new Thread(this); thread.start(); } if (c == gmCommand) { while (form.size() > 3) { form.delete(form.size()-1); } GoogleMaps gm = new GoogleMaps(APIKEY); if (latitude != 0 && longitude != 0) { Image map = null; try { int zoom_int = zoomGauge.getValue(); map = gm.retrieveStaticImage(240, 320, latitude, longitude, zoom_int, "png32"); } catch (Exception ex) { ex.printStackTrace(); } if (map != null) form.append(map); } } if (c == exitCommand) { thread = null; notifyDestroyed(); } }

   Select All

Note that no implementation is needed for the methods pauseApp and destroyApp.