[FIXED] Swing JTabbedPane how to set scroll width?

Issue

I use the following code to create a JTabbedPane

new JTabbedPane(JTabbedPane.LEFT,JTabbedPane.SCROLL_TAB_LAYOUT);

It results in a scroll that is smaller in width than the tab selection area

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How can I make the scroll width wider so that it fits the tab selection area?

Solution

You can extend BasicTabbedPaneUI and implement you own button in createScrollButton() providing new preferred size. It looks like BasicTabbedPaneUI has its own private implementation for these buttons - ScrollableTabButton. You can create something similar, like the following:

public class ExtendedTabbedPaneUI extends BasicTabbedPaneUI {

    @Override
    protected JButton createScrollButton(int direction) {
         if (direction != SOUTH && direction != NORTH && direction != EAST &&
                                   direction != WEST) {
             throw new IllegalArgumentException("Direction must be one of: " +
                                                "SOUTH, NORTH, EAST or WEST");
         }

         //return new ScrollableTabButton(direction);

         return new BasicArrowButton(direction,
            UIManager.getColor("TabbedPane.selected"),
            UIManager.getColor("TabbedPane.shadow"),
            UIManager.getColor("TabbedPane.darkShadow"),
            UIManager.getColor("TabbedPane.highlight")) {

            @Override
            public Dimension getPreferredSize() {
                int maxWidth = calculateMaxTabWidth(JTabbedPane.LEFT);
                return new Dimension(maxWidth, super.getPreferredSize().height);
            }
        };
    }
}

And to setup new UI:

tabbedPane.setUI(new ExtendedTabbedPaneUI());

Answered By - tenorsax
Answer Checked By - Willingham (JavaFixing Volunteer)