Customized Radio Button

I need to show a small, right-pointing, custom-color filled triangle, beside a radio-button's LHS (which would belong to a button-group) which has just gained focus in the group (by key-board arrow-key navigation). [i.e. the triangle would point towards the circle of the radio-button component]. Several alternatives are rushing through my mind w.r.t. a possible implementation. But, before I design it fresh from the grass-root level, I wanted to see if some one has a pointer to some concept-implementation/solution, in the interest of saving some time.

Some alternatives that I'm considering:

1. Custom UI delegate creation and then setUI on the Radio-Button.

2. Packing a parallel, thin, vertical JPanel on the LHS of the circles of the radio-buttons (of the associated radio-group) and then computing the Y-co-ordinate of the center of the circle, of the just-focus-gained radio-button, in its focusGained() event-handler, to compute the offset of the Box (of the vertical BoxLayout) in the LHS-JPanel and then rendering a Path2D-based triangle, which will then be custom-color-filled and then making that box visible (in the LHS JPanel vertical-stack - it will have at most one box visible at a time - the one associated with the focusGained() radio-button) and then, vertical-aligning the LHS-JPanel and the button-group with the Spring Layout (so that they move-together over the main-panel-resizing operation, if undertaken by the user).

3. Customizing a radio-button, by putting it in a JPanel with horizontal BoxLayout, (whose first box will hold the Java2D-rendered triangle) and making all such JPanel-embedded radio-buttons members of the covering group.

Please comment on the above and/or please provide some example pointers of similar attempts. Thanks a lot.

Could be useful to you: Toggle Button Icons « Java Tips Weblog

Also see the API for the various set...Icon methods inherited from AbstractButton.

db

Quote:

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Also see the API for the various set...Icon methods inherited from AbstractButton.

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Actually, as per your requirement and as there isn't a setFocusedIcon method, it may be better to implement the behavior in the icon's paintIcon.

Code:

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import darrylbu.renderer.RadioButtonIcon;
import java.awt.*;
import javax.swing.*;

public class RadioButtonFocusIcon {

  public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {

      public void run() {
        new RadioButtonFocusIcon().makeUI();
      }
    });
  }

  public void makeUI() {
    JPanel panel = new JPanel(new GridLayout(0, 1));
    ButtonGroup group = new ButtonGroup();
    Icon icon = new ArrowIcon();
    for (int i = 0; i < 5; i++) {
      JRadioButton button = new JRadioButton("Choice" + i);
      button.setIcon(new RadioButtonIcon(button, icon,
              SwingConstants.LEFT, SwingConstants.CENTER));
      group.add(button);
      panel.add(button);
    }

    JFrame frame = new JFrame();
    frame.add(panel);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }
}

class ArrowIcon implements Icon {

  static final int SIDE = 12;
  static final int[] xPoints = {1, 11, 1};
  static final int[] yPoints = {1, 6, 11};

  public void paintIcon(Component c, Graphics g, int x, int y) {
    if (c.isFocusOwner()) {
      Graphics g2 = g.create(x, y, SIDE, SIDE);
      g2.setColor(Color.RED);
      g2.fillPolygon(xPoints, yPoints, 3);
      g2.dispose();
    }
  }

  public int getIconWidth() {
    return SIDE;
  }

  public int getIconHeight() {
    return SIDE;
  }
}

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db

Now if I had known you weren't really interested, I wouldn't have bothered.

db

Typical "one post and out of here" poster.

Hi Darryl: Thanks for posting the pointers and the sample code. Much appreciated. I've already added my nice comments for you with the help of the forum's reputation button. Just started getting a feel for this forum and its mechanisms. BTW: Are you permanently located in Goa or just site-seeing there presently (and avoiding the US's cold weather :-))?

Quote:

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Are you permanently located in Goa or just site-seeing there presently (and avoiding the US's cold weather :-))?

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I live and work here. No idea about the weather in the US.

db