Toggle a component's 'enable' property

问题:

I have two radio buttons in a button group and in the same panel I have a text box and a button. I want to enable the text box and the button only when the second button is selected and be disabled when the other radio button is selected. I've tried this and it didn't work.

private void radio_button2ActionPerformed(java.awt.event.ActionEvent evt) {
if(buttonGroup1.getSelection()==radio_button2)
{
    button.setEnabled(true);
    textbox.setEnabled(true);
}

Where have I gone wrong?

回答1:

You don't want to use an ActionListener because the event only fires when you click the button. Instead you can use an ItemListener so an event is generated when the item is selected or deselected (by clicking the other radio button). Something like:

radioButton2.addItemListener( new ItemListener()
{
    public void itemStateChanged(ItemEvent e)
    {
        JRadioButton button = (JRadioButton)e.getSource();
        component1.setEnabled( button.isSelected() );
        component2.setEnabled( button.isSelected() );
    }
});