midlet and thread - just begin

[gilloull]

Hi all

I am starting with J2ME and I get problems very quickly.

I have a midlet which displays "Hello".

When I push a command I want the midlet creating a thread which says "something else".

If, in this new thread, I push something like back command, I want the thread to be killed and give the hand back to the midlet.
else, I want to wait until the command is activated.

this is my code :

public class Visu extends MIDlet implements CommandListener
{

	public static final Form form = new Form("Test");
	
	Form currentForm = form;
	
	public static TextField TextField = new TextField("","",32,0);
    
	public static final	Command readInfoCmd = new Command("Read info" , Command.ITEM , 0 ),
				Command exitCmd     = new Command("Exit"      , Command.EXIT , 1 );
		
        boolean running = false;

        private StringItem screenText = new StringItem(null, ("\n\n"));
    
        ThreadFactory currentThread = null;
        TestThread TestThread;
	
	
        public Visu()
	{
		super();
	}
	

        [...]
	

	public void commandAction(Command c, Displayable d)
	{			
		if (c == exitCmd)
			exit();
	
		else if(c == readInfoCmd)
		{
			
			TestThread    = new TestThread(false);
	                currentThread = TestThread;
	                displayT();
		}	
	}


	private void displayT()
	{	
		currentForm = currentThread.getForm();
		currentThread.setCommandListener(this);
		currentThread.setDisplay(Display.getDisplay(this));
		
		if(currentThread !=null)
		{
			currentThread.start();
	                Display.getDisplay(this).setCurrent(form);
		}
		else
			Display.getDisplay(this).setCurrent(form);
	}
	
	
	private void exit()
	{
		try
		{
			destroyApp(false);
			notifyDestroyed();
		}
		catch (MIDletStateChangeException ex)
		{
			screenText.setText(screenText.getText() + ex.toString());
		}
	}
}

and my thread is like this :

public class TestThread extends ThreadFactory
{
	boolean running = false;
	boolean forever = false;

	
	public TestThread(boolean forever)
	{
		super();
		this.forever = forever;
		currentForm =  new Form("In the thread");
	}
 

        [...]

		
	public void commandAction(Command c, Displayable d)
	{
		if (c == backCmd)
		{
			display("Bye Bye !");
			currentForm = Visu.form;
			running = false;
		}
	}
	
	
	public void run()
	{

		running = true;

		display("The thread is running");
		
		while(running == true)
		{

		}
	}
		
	
         protected void stopTest()
        {
                display ("back to main menu");
	        running = false;
        }
}

(threadFactory is an abstract class which extends Thread).

So if I push "Read Info" in the midlet, I correctly go into my thread.

But When I push "back" into the thread, I never see "back to main menu" and nothing else can be done excepted exit the application.

Questions :

- Do you see where could be the problem ?

- Do threadFactory (or TestThread) has to implement CommandListener to detect actions on Command ?

- The code is from an other guy and I don't get the use of boolean forever, do you understand futur advantages ?

- Do you know some easy "how to" about threads in J2ME (or boooks - I have "Beginning J2ME Plateform From Novice to Professional", from Sing Li and Jonathan Knudsen, but it never explain nicely how to do, I don't like very much this book) ?

(The final objectif of this midlet is to have some items in a menu and create a thread each time a item is select, then perform actions and finally go back to the main menu of the midlet and have the choice again between all commands).


Thanks for taking time !

[roopesh.kumar]

Hi all
- Do threadFactory (or TestThread) has to implement CommandListener to detect actions on Command ?

1) Yes. you have to implement CommandListener in TestThread. And setCommandListener of the form to it.