JTabbedPane: avoid automatic re-ordering tabs if s

问题:

a JTabbedPane is just what I need for my purpose. I have very limited horizontal space, so my Tabs get stacked, which is perfectly ok.

But the default behaviour is that if user clicks on a Tab, the *Tabs get re-sorted so that the active Tab becomes the lower-mos*t. What looks very intuitive and logical in theory, is a nightmare in practical use, because the users loose track of "which was which". Its just simply plain confusing, I am told again and again.

I guess it should be possible to override some method of the UI to avoid this behaviour (and I dont care whether this would be physically possible with paper cards :-) .

Has anyone any idea where I need to do that? I am using Nimbus LAF, which does not seem to make it easier.

(I thought about using radiobuttons/cardLayout, but I need to put a custom panel in the tab title, and radiobuttons can only have a string or icon. Same for JToggleButton...)

Any hints are greatly welcome!

Thanks & Kind regards, Philipp

回答1:

Okay, I found the Problem. In

package javax.swing.plaf.basic.BasicTabbedPaneUI;

it says something like this

// Rotate run array so that selected run is first
            if (shouldRotateTabRuns(tabPlacement)) {
                rotateTabRuns(tabPlacement, selectedRun);
            }

Its a pity that there seems to be no easy set-a-flag-and-there-you-go-way is for changing that.

Although you should be fine if you omitted the call to rotateTabRuns(tabPlacement, selectedRun); or change shouldRotateTabRuns(tabPlacement) for that matter... however, to do so you would have to override a whole bunch of classes... depending on which plaf you use.

It inherits like this

Basic > Synth > Nimbus

And on each L&F-level there are several classes to customize... I didn't count.

Hope it helps! :D

Edit Oh yeah... @mkorbel already provided sort of the solution with this aephyr why not use that?

回答2:

sscce for potential answerer(s) for Nimbus L&f (by using another L&f isn't possible to reproduce this funny issue), in case that Containers#Size packed Tabs to the two or more Lines,

as I know there is only one possible solutions (without override NimbusTabbedPaneUI) by aephyr

from sscce

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

public class TabbedPane {

    private static final long serialVersionUID = 1L;

    public TabbedPane() {
        JPanel jp = new JPanel();
        jp.setLayout(new BorderLayout());
        JTabbedPane tb = new JTabbedPane();
        //tb.setUI(new CustomTabbedPaneUI());
        tb.add("Tab1", new JTextArea(10, 20));
        tb.add("Tab2", new JTextArea(10, 20));
        tb.add("Tab3", new JTextArea(10, 20));
        tb.add("Tab4", new JTextArea(10, 20));
        tb.add("Tab5", new JTextArea(10, 20));
        jp.add(tb, BorderLayout.CENTER);
        //add(jp, BorderLayout.CENTER);
        //tb.setEnabledAt(1, false);
        //tb.setEnabledAt(3, false);
        JFrame frame = new JFrame();
        frame.setLayout(new BorderLayout());
        frame.add(jp, BorderLayout.CENTER);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        try {
            for (UIManager.LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (Exception system) {
            system.printStackTrace();
        }
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                TabbedPane tP = new TabbedPane();
            }
        });
    }
}

回答3:

It's a bit of a hack but you can override the Nimbus defaults to have the plain old Java look-and-feel for the tabbed pane, whilst keeping everything else the same. The plain Java look-and-feel for a tabbed pane doesn't do the annoying reordering. Just store the defaults before you set the look-and-feel and then set them back.

// get the defaults to keep
HashMap<Object, Object> defaultsToKeep = new HashMap<>();
for (Map.Entry<Object, Object> entry : UIManager.getDefaults().entrySet()) {
    boolean isStringKey = entry.getKey().getClass() == String.class ;
    String key = isStringKey ? ((String) entry.getKey()):"";    
    if (key.startsWith("TabbedPane")) {
        defaultsToKeep.put(entry.getKey(), entry.getValue());
    }
}

// set nimbus look and feel
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
    if ("Nimbus".equals(info.getName())) {
        UIManager.setLookAndFeel(info.getClassName());
        break;
    }
}

// set back your originals
for (Map.Entry<Object, Object> entry : defaultsToKeep.entrySet()) {
    UIManager.getDefaults().put(entry.getKey(), entry.getValue());
}

JFrame.setDefaultLookAndFeelDecorated(true);