How to detect when/which key is pressed?

[qwerty_wwd]

Hi!

I would like to make a program that increments counter when I press RIGHT or number 6 key and decrements it when I press LEFT or number 4. How can I do that?

Should i use command listener? I try it but I didn't get it work.

[hemanthnarayanan]

hi,
It would be much more easier to make use of the OfferKeyEventL() to achieve what u desire. in the OfferKeyEventL() Method u can get the Keycode of the key pressed. every key will have a unique key code. so once u know the key code for 6 or right button, u can compare that in the OfferKeyEventL() and if the comparison is true then it means that u have pressed 6 or right key, and then u can correspondingly perform the desired operation like incrementing a counter and so on.
with regards,
Hemanth.

[qwerty_wwd]

Will that work in Java also?

[soku123]

Hi,
No command listener wont solve your problem.There are methods called keypressed,keyReleased and keyRepeated where u will recieve the key events.
a particular value is there for key 6 and 4.u will get this from printing out the keyCode values.....Sorry this is the case with j2me

[wang_shui]

Hi,

the following document solves ur problem
http://www.forum.nokia.com/info/sw.n..._v1_0.pdf.html

Wang

[shmoove]

This tutorial takes you up to a stage where you are moving an image on screen in response to key presses. That should be easy to chance into incrementing counters.

shmoove

[qwerty_wwd]

This tutorial takes you up to a stage where you are moving an image on screen in response to key presses. That should be easy to chance into incrementing counters.

shmoove

Thaks for the tutorial.

How can I get this KeyRepeated event work? If I do it like this KeyPressed works fine but if I keep key pressed nothing happens.

protected void paint( Graphics g )
	{
		//set the current color of the Graphics contect to the specified RRGGBB colour
		
                
                g.setColor( 0xFFFFFF );
                g.fillRect( 90, 90, 30, 30 );
                g.drawLine(50+Startup.counter,50,50+Startup.counter,60);
                
                g.setColor( colour );
                g.fillRect( 50, 50, Startup.counter, 10 );
                g.drawString(Integer.toString(Startup.counter),100,100,16|1);
	}
	
	/* 
	* called when a key is pressed and this Canvas is the
	* current Displayable 
	*/
	protected void keyPressed( int keyCode )
	{
		//get the game action from the passed keyCode
		int gameAction = getGameAction( keyCode );
		switch( gameAction )
		{
			case LEFT:
			//set current colour to red
			colour = 0xFF0000; 
                        Startup.counter--;
			break;
			
			case RIGHT:
			//set current colour to green
			colour = 0x00FF00;
                        Startup.counter++;
			break;
			
					}
		//schedule a repaint of the Canvas after each key press as
		//currently do not have any main game loop to do this for us.
		repaint();
	}

	/* 
	* key repeated
	*/
	protected void keyRepeated( int keyCode )
	{
            int gameAction = getGameAction( keyCode );
		switch( gameAction )
		{
			case RIGHT:
                        Startup.counter++;
                        repaint();
			break;
                }
                
	}

[EDIT]
Sorry, that code works fine. My emulator just doesn't understand it.


But now I have a new question. Is it possible to use numpad keys without using Canvas? I have tried but it says cannot find symbol: method getGameAction(int). I have imported javax.microedition.lcdui.*; but it won't help.

[hartti]

getGameAction() is a method in Canvas. Unless you are displaying a canvas you cannot use it. If you are using the high-level UI elements like Form and TextBox, you are stuck with using Commands

Hartti