Slide 3.10: Line-by-line anatomy of HelloMIDlet.java (cont.)   Slide 3.12: Line-by-line anatomy of HelloMIDlet.java (cont.)   Home

Line-by-line Anatomy of HelloMIDlet.java (Cont.)

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A MIDlet goes through the following states:

1. When the MIDlet is about to be run, an instance is created. The MIDlet's constructor is run, and the MIDlet is in the Paused state.


2. Next, the MIDlet enters the Active state after the application manager calls startApp( ).


3. While the MIDlet is Active, the JAM can suspend its execution by calling pauseApp( ), which puts the MIDlet back in the Paused state.


4. The application manager can terminate the execution of the MIDlet by calling destroyApp( ), at which point the MIDlet is Destroyed and patiently awaits garbage collection.

display = Display.getDisplay(this);
The method public static Display javax.microedition.lcdui.Display.getDisplay (MIDlet m) gets the Display object that is unique to this MIDlet.

cmdExit = new Command("Exit", Command.SCREEN, 1);
The constructor public javax.microedition.lcdui.Command(String label, int commandType, int priority) creates a new command object with the following parameters:

• label — The label string is what the application requests to be shown to the user to represent this command.


• commandType — The command types include BACK, CANCEL, EXIT, HELP, ITEM, OK, SCREEN, or STOP.
  ^†public static final int SCREEN specifies an application-defined command that pertains to the current screen.


• priority — The application uses the value to describe the importance of this command relative to other commands on the same screen.