4

I have a Java check box next to a text field.

When the check box gets selected, I want the text box to be enabled and when it isn't, I don't want it to be selected. I tried an if statement with the isSelected() method, but it didn't do anything.

How can I react to state changes of the JCheckBox?

Paŭlo Ebermann
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Jeff
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3 Answers3

15

Suggestion:

  1. Read the How to Use Check Boxes tutorial
  2. Register an ItemListener for the JCheckBox instance
  3. Compare state change (i.e. getStateChange()) to either ItemEvent.SELECTED, or ItemEvent.DESELECTED, and then appropriately invoke foo.setEnabled, where foo is the JTextBox instance.

Here's an SSCCE:

public final class JCheckBoxDemo {
    public static void main(String[] args){
        SwingUtilities.invokeLater(new Runnable(){
            @Override
            public void run() {
                createAndShowGUI();             
            }
        });
    }

    private static void createAndShowGUI(){
        final JFrame frame = new JFrame("JCheckBox Demo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(JCheckAndTextPane.newInstance());
        frame.setSize(new Dimension(250, 75)); // for demonstration purposes only
        //frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    private static final class JCheckAndTextPane extends JPanel{
        private JCheckAndTextPane(){
            super();

            // Create components
            final JTextField textField = new JTextField("Enabled");
            final JCheckBox checkBox = new JCheckBox("Enable", true);
            checkBox.addItemListener(new ItemListener(){
                @Override
                public void itemStateChanged(ItemEvent e) {
                    if(e.getStateChange() == ItemEvent.SELECTED){
                        textField.setEnabled(true);
                        textField.setText("Enabled");
                    }
                    else if(e.getStateChange() == ItemEvent.DESELECTED){
                        textField.setEnabled(false);
                        textField.setText("Disabled");
                    }

                    validate();
                    repaint();
                }
            });

            add(checkBox);
            add(textField);
        }

        public static final JCheckAndTextPane newInstance(){
            return new JCheckAndTextPane();
        }
    }
}

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mre
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    2 notes. 1) An SSCCE should include the imports (not all of us run automagic IDEs that will figure them out!). 2) For tips on making great screen shots (especially getting rid of the 'stray pixels' in the rounded corners), see the [How do I create screenshots?](http://meta.stackexchange.com/questions/99734/how-do-i-create-a-screenshot-to-illustrate-a-post) FAQ. Those 2 points aside, +1. – Andrew Thompson Aug 24 '11 at 14:16
2

Use the isSelected method.

You then use an ItemListener so you'll be notified when it's checked or unchecked.

And depending on the state of the isSelected method, then you can enable or disable the JTextBox.

Codemwnci
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0

// >Click checkbox > Add Event handler > Item > ItemStateChange > Type the code

// chckBox1 is my Variable name

    chckBox2.addItemListener(new ItemListener() {
        public void itemStateChanged(ItemEvent e) {

            if(chckBox2.isSelected()) {
                txtAddCandles.setEnabled(true);
            }

        }
    });
Tedi
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