Personal Basis Profile

• This profile provides two major features
  • Support for basic GUI functionality
  • Lifecycle management of applications
• The GUI functionality is provided by a subset of the AWT, without most of the widgets
• A basic lifecycle model to start, stop, suspend and resume applications is supported using Xlets
• The Sun Personal Basis distribution includes a Programmer's Guide

An AWT application

An application to show a button and print a message when pressed is

This application will not work in Personal Basis Profile, because there is no Button object

Converting to an AWT application that works under PBP

• The PBP has the Frame widget, all of the AWT events and AWT listeners, and the AWT geometry managers
• It has graphics objects, and basic drawing functions
• It doesn't have the widgets such as the Button
• All that is needed (:-) is to define your own widgets, and write code for them

An AWT application working under PBP

To compile the demo

javac -classpath .:/usr/local/personaljava/j2me-pp1.0/lib/personal.jar *.java

/usr/local/personaljava/j2me-pp1.0/bin/cvm PPButtonDemo

Xlets

• An ordinary application has a main() method, and is started by calling this method
• The life cycle of an application is start - stop
• A downloadable application may have further stages
  • download from some source
  • initialise the application
  • start the application
  • suspend the application
  • restart the application
  • stop the application
  • discard the files
• The life-cycle of a downloadable application should include the environmental aspects in which it appears to "start - stop"
• These applications are managed applications
• An Xlet is the PBP managed application type

Xlet life-cycle

Xlet interface

An Xlet is informed about each state change, as the management environment calls the methods of the Xlet interface

Xlet example

An example using the PPButton is To run the Xlet

cvm com.sun.xlet.XletRunner -name XletButtonDemo -path .



 Xlet communication 



  

      Xlets controlled by the same manager can get references to each other
      using the IxcRegistry
  
  

      Xlets can then call methods on each other
  
  

      e.g. a Timer Xlet running on a TV can ask the current display Xlet to show
      a different program
  




Jan Newmarch (http://jan.newmarch.name)
jan@newmarch.name


Last modified: Fri Dec  3 19:33:17 EST 2004


Copyright ©Jan Newmarch