JComboBox width

Question

I have created a jComboBox but it takes the full width of the frame. how to set the width fixed.

yes borderlayout for the frame and box layout for the panel. i am adding the code here:

import javax.swing.*;
import java.awt.BorderLayout;

public class Window8  {

    JFrame frame;
    JPanel panel;
    JComboBox combo;
    public void go(){

    String[] option = { "STUDENT", "TEACHER" };

    combo.setPreferredSize(new Dimension(1,25));
    combo = new JComboBox(option);
    menu.setSelectedIndex(0);

    frame = new JFrame("DELETION"); 
    frame.setLocationRelativeTo(null);
    frame.setSize(400, 300);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);

    panel = new JPanel();
    panel.setLayout(new BoxLayout(panel,BoxLayout.Y_AXIS));

    frame.getContentPane().add(BorderLayout.NORTH,panel);
    panel.add(combo);   
}

i have added my code. please have a look at it. – Suman.hassan95 Jan 07 '11 at 18:57 — Suman.hassan95, Jan 07 '11 at 18:57
Reformatted code; copyedited; please revert if incorrect. – trashgod Jan 07 '11 at 20:33 — trashgod, Jan 07 '11 at 20:33

score 28 · Answer 1 · edited Apr 27 '11 at 23:26

28

The width is automatically determined by the width of the largest item added to the combo box. You can control the display by using:

comboBox.setPrototypeDisplayValue("text here");

You might also consider using the Combo Box Popup to control the popup size.

Edit:

Since you added code that shows you are using a BoxLayout you can try the following:

comboBox.setMaximumSize( comboBox.getPreferredSize() );

Or you can do something like:

JPanel wrapper = new JPanel();
wrapper.add( comboBox );
panel.add( wrapper );

Read the section from the Swing tutorial on Using Layout Managers to understand how these suggestions work.

edited Apr 27 '11 at 23:26

Electrons_Ahoy

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answered Jan 07 '11 at 18:42

camickr

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1

Using `setPrototypeDisplayValue` with a sensitive option helps on properly resizing the JComboBox while allowing it to have a different size according to container definition. Thanks! – Alfabravo Nov 16 '17 at 22:02

Romain Hippeau · Answer 2 · 2011-01-07T19:09:00.903

4

try comboBox.setPreferredWidth(200); or some other value to set the width

jzd is right. The actual API is setPreferredSize(new Dimension(...));

edited Jan 07 '11 at 19:09

answered Jan 07 '11 at 18:42

Romain Hippeau

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i tried but gives this error. " The method setPreferredWidth(int) is undefined for the type JComboBox" – Suman.hassan95 Jan 07 '11 at 18:53
2

Looking in the API, the exact method is: setPreferredSize(Dimension preferredSize) – jzd Jan 07 '11 at 18:57

score 1 · Answer 3 · answered Jan 28 '13 at 23:34

1

You might want to use setSize() method.

combo.setSize(200, combo.getPreferredSize().height);

answered Jan 28 '13 at 23:34

Ned

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score 1 · Answer 4 · answered Jan 07 '11 at 18:59

1

Use a different LayoutManager. Try FlowLayout.

answered Jan 07 '11 at 18:59

jzd

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The width will be automatically determined based on the contents or use setPreferredSize() or camickr's suggestion. But if you put it in a layout that stretches it will not matter. – jzd Jan 07 '11 at 19:25

score 1 · Answer 5 · answered Jan 07 '11 at 21:07

Here is something you can do with box layout.

Change axis to line axis, Add
horizontal glue, Add rigid area,
place the component

. code snippet below:

panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.LINE_AXIS));
panel.add(Box.createHorizontalGlue());
panel.add(Box.createRigidArea(new Dimension(10, 0)));
panel.add(combo);
frame.getContentPane().add(BorderLayout.NORTH, panel);

score -1 · Answer 6 · answered Oct 20 '22 at 06:23

-1

Don't use JCombobox<>() instead of that use Combobox<>() then width won't change, also if you set preferred size it won't change with Combobox so use this instead

answered Oct 20 '22 at 06:23

Shweta Mishra

1

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`ComboBox` is a heavyweight AWT component. AWT components and Swing components don't always play well together. – Gilbert Le Blanc Oct 20 '22 at 07:25

JComboBox width

6 Answers6

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