Image in button - j2me

Question

Hi,

I am trying to build a simple menu-based GUI with J2ME. The menu entries are currently objects of classes derived from the class Button. Is there any way I can:

1. Replace the text in the button and have an image show instead, sort of an icon?

2. Make the text and image appear side by side on the same menu bar.

If my question is not clear, please let me know and I will edit it.

Thanks, Sriram.

Answer 1

You may create your own Item that looks like a button by extending CustomItem class

This is a whole working MIDlet with good MyButton class.

import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.CustomItem;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.Item;
import javax.microedition.lcdui.ItemStateListener;
import javax.microedition.midlet.MIDlet;

public class TestMidlet extends MIDlet implements ItemStateListener
{
    class MyButton extends CustomItem
    {
        // Button's image
        private Image i=null;
        // Is the button currently down
        private boolean down=false;
        // How many times has the button been clicked
        private int clicks=0;

        // Constructor
        public MyButton(Image _i)
        {
            super("");
            i=_i;
        }
        // Allows to change image
        public void setImage(Image _i)
        {
            i=_i;
            repaint();
        }
        // Allows to get current image
        public Image getImage()
        {
            return i;
        }
        // Tells if the button was clicked
        public boolean isClicked()
        {
            if(clicks>0)
            {
                clicks--;
                return true;
            }
            return false;
        }
        // Tells if the button is currently down
        public boolean isDown()
        {
            return down;
        }
        // Functions that set the button to down or up states
        public void setDown()
        {
            down=true;
            repaint();
            notifyStateChanged();
        }
        public void setUp()
        {
            down=false;
            clicks++;
            repaint();
            notifyStateChanged();
        }

        // Minimal button size = image size
        protected int getMinContentHeight()
        {
            return i.getHeight();
        }
        protected int getMinContentWidth()
        {
            return i.getWidth();
        }
        // Preferred button size = image size + borders
        protected int getPrefContentHeight(int width)
        {
            return i.getHeight()+2;
        }
        protected int getPrefContentWidth(int height)
        {
            return i.getWidth()+2;
        }
        // Button painting procedure
        protected void paint(Graphics g,int w,int h)
        {
            // Fill the button with grey color - background 
            g.setColor(192,192,192);
            g.fillRect(0,0,w,h);
            // Draw the image in the center of the button
            g.drawImage(i,w/2,h/2,Graphics.HCENTER|Graphics.VCENTER);
            // Draw the borders
            g.setColor(down?0x000000:0xffffff);
            g.drawLine(0,0,w,0);
            g.drawLine(0,0,0,h);
            g.setColor(down?0xffffff:0x000000);
            g.drawLine(0,h-1,w,h-1);
            g.drawLine(w-1,0,w-1,h);
        }
        // If FIRE key is pressed, the button becomes pressed (down state)
        protected void keyPressed(int c)
        {
            if(getGameAction(c)==Canvas.FIRE);
                setDown();
        }
        // When FIRE key is released, the button becomes released (up state)
        protected void keyReleased(int c)
        {
            if(getGameAction(c)==Canvas.FIRE);
                setUp();
        }
        // The same for sensor screens
        protected void pointerPressed(int x,int y)
        {
            setDown();
        }
        protected void pointerReleased(int x,int y)
        {
            setUp();
        }
    }

    MyButton b=null;

    public void itemStateChanged(Item item)
    {
        if(item==b)
        {
            if(b.isClicked())
                System.out.print("clicked, ");
            System.out.println(b.isDown()?"currently down":"currently up");
        }
    }
    public void startApp()
    {
        try
        {
            Form f=new Form("Example");
            b=new MyButton(Image.createImage("/icon.png"));
            f.append(b);
            f.setItemStateListener(this);
            Display.getDisplay(this).setCurrent(f);
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
    }
    public void pauseApp()
    {
    }
    public void destroyApp(boolean unconditional)
    {
        notifyDestroyed();
    }
}