How to make buttons on a canvas in J2ME?

Question

I'm new to J2ME and I was trying to make a page which has some logos(images) at the top, two buttons arranged side-by-side(one and only one of which is always selected) and a table displaying data below the buttons. The data is displayed according to which button is currently selected. I'm extending canvas and I was able to make the tables and draw the images but I could'nt find anything on making buttons on the internet. So how should I go about it? If anyone could point me to some sample code, that would be great too!

Answer 1

Not that hard, but you need to draw everything yourself. That means, buttons are either using a plain rectangle with text in the middle (different colours could indicate which is highlighted), or they could be images which you made yourself.

If they are arranged in a square, you need to keep track of which button is selected, and then change the selected index whenever a direction key is pressed.

Answer 2

iirc my favorite way to paint buttons on canvas was drawing and filling rounded rectangles. There are methods in Graphics package that do that; to get desired effect I just called them with same or off-by-one parameters I don't recall exactly.

• note if you are going to write text over "buttons", consider using Font.getHeight and Font.stringWidth to determine size of rectangle to draw around

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...logos(images) at the top, two buttons arranged side-by-side(one and only one of which is always selected) and a table displaying data below the buttons

BTW is there a reason why you don't use Form ? I ask because StringItem objects, created with appearance BUTTON and having ItemCommandListener look and behave like buttons but are easier to code. The rest also looks doable with Form , one just may need CustomItem to display the table like you describe

Answer 3

The default UI does not have buttons, only commands. You have to make one yourself or use a GUI framework like LWUit.