CODEWITHSUNDEEP
javaswinglayout-manager
user330315
user330315

Reputation:

BorderLayout - prevent "center" component to be "cut off"

I have a JPanel that contains two JLabel. The panel uses a BorderLayout.

One JLabel is put into BorderLayout.CENTER position, the other in BorderLayout.PAGE_END

When I resize the panel so that it does not have enough vertical space to show both labels, the centered label is always overwritten (cut off) by the label in the PAGE_END position.

As the information displayed in the centered label is more important than the other, I would like the centered label to overlap (or cut off) the label below it.

It seems that BorderLayout (and GridBagLayout as well) always paints the components from "top to bottom" and those that are painted "later" will overwrite the ones painted before.

Is there some way I can convince BorderLayout (or any other LayoutManager) to assume that a certain component should always be "at the top"?

I tried using 

panel.setComponentZOrder(label1, 1);
panel.setComponentZOrder(label2, 0);

but that didn't make a difference.

Upvotes: 2

Views: 1722

Answers (2)

Andrew Thompson
Andrew Thompson

Reputation: 168845

Call setMinimumSize(Dimension) on the top-level container when there is enough text in the center label.

Upvotes: 2

trashgod
trashgod

Reputation: 205875

One approach would be to use a custom variation of GridLayout that respects preferred sizes. PreferredSizeGridLayout using the PreferredBoundable implementation is an example.

Addendum: Here's the test code I tried. Without change, the lower label "slides" beneath the upper, but you'll have to handle the horizontalAlignment property.

public class PreferredLayoutTest extends JPanel {

    public PreferredLayoutTest() {
        this.setLayout(new PreferredSizeGridLayout(0, 1));
        this.add(createLabel("One"));
        this.add(createLabel("Two"));
    }

    private JLabel createLabel(String s) {
        JLabel label = new JLabel(s);
        label.setOpaque(true);
        label.setBackground(Color.lightGray);
        label.setFont(label.getFont().deriveFont(36f));
        return label;
    }

    private void display() {
        JFrame f = new JFrame("PreferredLayoutTest");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(this);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                new PreferredLayoutTest().display();
            }
        });
    }
}

Upvotes: 2

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