JAVA GUI stuff

1. on radiobuttons:

JRadioButton a= new JRadioButton("A");
JRadioButton b= new JRadioButton("B");
ButtonGroup bg = new ButtonGroup();
bg.add(a); bg.add(b);
JPanel mode = new JPanel(new GridLayout(1, 1));
mode.add(bg);

ERROR:
Incompatible type for method. Can't convert javax.swing.ButtonGroup to java.awt.Component.

eh?

2. also, how do i use the isSelected method so that radiobutton "A" is selected on load?

3. finally, x.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); in void main, but it doesn't work, something like EXIT_ON_CLOSE not declared...

mode.add(a); mode.add(b);

The ButtonGroup is a manager, it isn't added to anything.

Quote:

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Originally posted by quipy
3. finally, x.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); in void main, but it doesn't work, something like EXIT_ON_CLOSE not declared...

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I remember hitting this bug when I was in school. Try this instead :

Code:

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x.addWindowListener(new WindowAdapter()
{
    public void windowClosing(WindowEvent we) { System.exit(0); }
});

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Where x is the JFrame as you have indicated.

:)

Quote:

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Originally posted by quipy

2. also, how do i use the isSelected method so that radiobutton "A" is selected on load?

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Use a.setSelected(true) in the form constructor

Quote:

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3. finally, x.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); in void main, but it doesn't work, something like EXIT_ON_CLOSE not declared...

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You need JDK 1.4 for that. You can also use 3 but that didn't always work in the lower versions. Your best bet is the windowadapter