Changes

== Step 23 - In the field changed method, we push another screen into view when the button is pressed ==== Step 24 - The LocationTracker class is pushed into view and so it also extends the MainScreen class ==== Step 25 - To get the location of the user in the LocationTracker class, we need to have a class that gets the users location ==== Step 26 - The MyLocationListener class implements LocationListener, so the class can be notified as the users location is updated ==== Step 27 - The locationUpdated method gets the latitude and the logitude of the user and saves then in two instance variables of the MyScreen class ==== Step 28 - In the LocationTracker class, we define some RichTextFields to output the collected value of the latitude and longitude ==== Step 29 - We also create a BitMap object and configure its weight and height using the methods defined in the BlackBerry docs ==== Step 30 - The BitMap object, SeparatorField object and RadioButtonField objects are added to the screen ==