Fixed size of panel in frame

Question

I have added some components to JPanel which is set to grid layout, and I'm adding this to JFrame which is set to border layout. But I want to fix the size of the panel. When my window is maximized, the size of all components are increasing. I want the panel at the center of the window, with fixed size even if window is maximised.

*"please help me with some coding"* Please help yourself to a question & any sign of effort. SO is not a code generation machine. BTW - Don't use code formatting for text, and check the post formats as you expect in the preview. Voting to close. — Andrew Thompson, May 25 '12 at 06:28
If you provide some code, it will be better. For example, I would look in your code to see if and where you call `setPreferredSize`. — Radu Murzea, May 25 '12 at 06:29
If the panel contains human readable text, _don't do this_! Font metrics vary by platform. — trashgod, May 25 '12 at 14:17

score 3 · Answer 1 · edited May 23 '17 at 11:53

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Put the panel with GridLayout as a single component to a GridBagLayout with no constraint - it will be centered. Add the panel with GBL to the CENTER of the BorderLayout.

See this example for the above image.

The Nested Layout Example also uses GBL to center the image in the lower part of the scroll-pane on the right.

edited May 23 '17 at 11:53

Community

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answered May 25 '12 at 06:31

Andrew Thompson

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score 1 · Answer 2 · answered May 25 '12 at 06:36

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Well then you should not use BorderLayout, because that just fits the child components in. If you still want to use BoderLayout on the JFrame (because you need some side panel or something like that), You can just wrap your JPanel (with the GridLayout) into another JPanel with a GridBagLayout or BoxLayout or something similar and then put that other JPanel into the JFrame.

JPanel innerPanel = new JPanel();
innerPanel.setLayout(new GridLayout());
// fill and set your innerPanel

JPanel middlePanel = new JPanel();
middlePanel.setLayout(new GridBagLayout());
middlePanel.add(innerPanel, constraintsThatPlaceItWhereYouWantIt);

JFrame yourFrame = new JFrame();
yourFrame.setLayout(new BorderLayout());
yourFrame.add(middlePanel, BorderLayout.CENTER);

answered May 25 '12 at 06:36

brimborium

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`middlePanel.add(innerPanel, constraintsThatPlaceItWhereYouWantIt);` See my answer for why `constraintsThatPlaceItWhereYouWantIt` is redundant for centering a component in GBL. It links to example code. – Andrew Thompson May 25 '12 at 06:38
You are right, but I still always give constraints when adding, because of readability. And he might do some more advanced stuff with it regarding placement. – brimborium May 25 '12 at 06:41
`middlePanel.add(innerPanel /* put in center */);` ;) – Andrew Thompson May 25 '12 at 06:42
How about the last line: `yourFrame.add(middlePanel, BorderLayout.CENTER);`? Would you skip the `BorderLayout.CENTER` as well? I wouldn't although it is not neccessary. – brimborium May 25 '12 at 06:47

Liu guanghua · Answer 3 · 2012-05-28T02:26:53.100

    JFrame frame = new JFrame();
    frame.setSize(500, 500);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().setLayout(new BorderLayout());

    JPanel rootPanel = new JPanel();
    frame.getContentPane().add(rootPanel, BorderLayout.CENTER);
    rootPanel.setLayout(new GridBagLayout());

    JPanel contentPanel = new JPanel();

    Dimension dimension = new Dimension(300, 300);
    contentPanel.setMaximumSize(dimension);
    contentPanel.setMinimumSize(dimension);
    contentPanel.setPreferredSize(dimension);
    contentPanel.setBackground(Color.YELLOW);

    GridBagConstraints g = new GridBagConstraints();
    g.gridx = 0;
    g.gridy = 0;
    g.anchor = GridBagConstraints.CENTER;
    rootPanel.add(contentPanel, g);

    frame.setVisible(true);

1) Use code formatting 2) This is rarely, if ever, the answer. -1 — Andrew Thompson, May 25 '12 at 06:33

Fixed size of panel in frame

3 Answers3