JTextField - setColumns() method not working for me

Question

my problem is that my JTextField -setColumns(int)

"field1.setColumns(5);"

...doesn't work. I'm guessing its a layout manager problem. However, I'm learning from an exercise book. The only layouts I know are flowLayout, borderLayout and gridlayout.

To explain this code in short, whenever "field2" triggers an ActionEvent (by pressing the enter key) "field1" should change size.

I've placed a "System.out.println("ActionEvent detected") in the "actionPerformed" to prove an actionevent is being fired, so that isn't the problem. I've even printed "field1.getColumn" and it shows the correct changed value of 5, however... Its not just not visibly changing size at runtime.

Rather than a work around I was hoping somebody could explain the problem. A work around isn't going to help me learn, which is the whole purpose of tackling these book exercises.

Incase its important, I'm coding in netbeans. Thanks in advance for the help.

public class Exercise13_11 extends JFrame implements ActionListener
{
    private JTextField textField1, textField2;
    private JLabel label1, label2;
    private JRadioButton rButton1, rButton2, rButton3;

    public static void main(String[] args)
    {
        JFrame frame = new Exercise13_11();
        frame.setTitle("Exercise 13.11");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(450, 200);
        frame.setVisible(true);
    }

public Exercise13_11()
{
    // North Panel aligned and filled.
    JPanel northPanel = new JPanel();
    northPanel.setLayout(new FlowLayout(FlowLayout.CENTER));
    northPanel.add(label1 = new JLabel("Text Field"));
    northPanel.add(textField1 = new JTextField(20));
    northPanel.setToolTipText("Demonstrate JTextField");
    getContentPane().add(northPanel, BorderLayout.CENTER);

    // South panel now being filled...
    JPanel southPanel = new JPanel();
        southPanel.setLayout(new FlowLayout());

    JPanel alignmentPanel = new JPanel();
    alignmentPanel.setBorder(
                new javax.swing.border.TitledBorder("Horizontal Alignment"));
    alignmentPanel.add(rButton1 = new JRadioButton("Left"));
    alignmentPanel.add(rButton2 = new JRadioButton("Center"));
    alignmentPanel.add(rButton3 = new JRadioButton("Right"));

    ButtonGroup buttonGroup = new ButtonGroup();
    buttonGroup.add(rButton1);
    buttonGroup.add(rButton2);
    buttonGroup.add(rButton3);

    JPanel columnPanel = new JPanel();
    columnPanel.setBorder(new javax.swing.border.EtchedBorder());
    columnPanel.setLayout(new FlowLayout());
    columnPanel.add(label2 = new JLabel("Column Size"));
    columnPanel.add(textField2 = new JTextField(10));

    southPanel.add(alignmentPanel);
    southPanel.add(columnPanel);
    getContentPane().add(southPanel, BorderLayout.SOUTH);

    textField1.addActionListener(this);
    rButton1.addActionListener(this);
    rButton2.addActionListener(this);
    rButton3.addActionListener(this);        
}

public void actionPerformed(ActionEvent e)
{
    if (e.getSource() == textField1)
    {
        textField1.setColumns(5);
    }
    else if (e.getSource() == rButton1)
            textField1.setHorizontalAlignment(textField1.LEFT);
    else if (e.getSource() == rButton2)
            textField1.setHorizontalAlignment(textField1.CENTER);
    else if (e.getSource() == rButton3)
            textField1.setHorizontalAlignment(textField1.RIGHT);
 }

}

Try adding a frame.repaint() after you change the TextField's column size. It could be an issue with Frame not realizing that the text field has changed, so it doesn't bother to redraw it. — aoi222, Jan 16 '12 at 20:32

score 6 · Accepted Answer · answered Jan 16 '12 at 20:33

6

It's working, you just need to force the container to layout its components again. This can be achieved by invoking revalidate and then issuing a repaint request (to remove any visual artifacts).

answered Jan 16 '12 at 20:33

mre

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Wicked, I've not covered validate() in my book. But screw it, a repaint() by itself didn't work. Thank you so much – cworner1 Jan 16 '12 at 20:50
@cworner1, that was `revalidate()` not validate() that you should be using. – camickr Jan 16 '12 at 21:16
Netbeans doesn't recognise revalidate(). I'm guessing its not a method found in the Component class. – cworner1 Jan 17 '12 at 09:24
+1 it's a bug (which I wasn't aware of until today ;-) - JTextField should invalidate itself on setting the columns ... – kleopatra Jan 17 '12 at 10:58

score -1 · Answer 2 · edited Feb 02 '19 at 10:43

-1

The method .setColumns() (used with JFormattedTextField component) failed to work, due to use of a TitledBorder for the container where the JFormattedTextFields was put inside:

<container.setBorder(javax.swing.BorderFactory.createTitledBorder("central"));>

edited Feb 02 '19 at 10:43

Cody Gray - on strike

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answered Feb 02 '19 at 10:05

Angelo

1

JTextField - setColumns() method not working for me

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