JSplitPane SetDividerLocation Problem

Question

I have a JSplitPane which when shown should split the pane by 50%.

Now on giving an argument of 0.5 (as suggested) to setDividerLocation, Java seems to treat it as a normal number instead of a percentage. As in, the divider, instead of going to the middle of the pane, is almost at the start of the left pane (the pane is vertically split). Any work arounds?

score 28 · Answer 1 · answered Aug 14 '11 at 19:34

28

Am I missing something? There seem to be a lot of rather convoluted answers to this question... but I think a simple setResizeWeight(0.5) would solve the issue ... it's described in the SplitPane Tutorial

answered Aug 14 '11 at 19:34

Sam Dealey

371
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10

Oh oops, I overlooked that in the comments. Thanks. Seems odd though the most popular answer didn't mention it... on a question that's 2 yrs old now. – Sam Dealey Aug 16 '11 at 03:14

score 17 · Answer 2 · answered Dec 10 '09 at 07:08

17

The setDividerLocation( double ) method only works on a "realized" frame, which means after you've packed or made the frame visible.

The setDividerLocation( int ) method can be used at any time.

answered Dec 10 '09 at 07:08

camickr

321,443
19
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288

Which is obviously understandable – user1593165 Feb 07 '20 at 15:35

score 8 · Answer 3 · answered Dec 28 '12 at 19:51

You can only set the split pane divider's location as a percentage when the split pane is visible. You can tap into the split pane owner's events to determine when its OK to set the divider's location. For example:

public class MyFrame extends JFrame {

  public MyFrame() {

    final JSplitPane splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT);
    // ... set up the split pane, and add to the frame ...

    // Listen for the frame's "shown" event.

    addComponentListener(new ComponentAdapter() {

      @Override
      public void componentShown(ComponentEvent componentEvent) {

        // Set the divider location to 20%.
        // This works because we know the pane is visible.

        splitPane.setDividerLocation(.2);

        // Stop listening for "shown" events.

        removeComponentListener(this);
      }

    });

    pack();
  }
}

score 3 · Answer 4 · answered Jun 02 '10 at 10:20

3

this fixes it:

public class JSplitPane3 extends JSplitPane {
    private boolean hasProportionalLocation = false;
    private double proportionalLocation = 0.5;
    private boolean isPainted = false;

    public void setDividerLocation(double proportionalLocation) {
        if (!isPainted) {
            hasProportionalLocation = true;
            this.proportionalLocation = proportionalLocation;
        } else {
            super.setDividerLocation(proportionalLocation);
        }
    }

    public void paint(Graphics g) {
        super.paint(g);
        if (!isPainted) {
            if (hasProportionalLocation) {
                super.setDividerLocation(proportionalLocation);
            }
            isPainted = true;
        }
    }

}

answered Jun 02 '10 at 10:20

david_p

5,722
1
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26

Just for clarification I have gotten it to work using only paint() and no hasProportionalLocation if I specify it manually in the code. Much shorter than this monstrosity – TheLQ Jul 09 '10 at 08:06
Thanks. Just came across this and it has been bugging us for ages. +1 – Andez Feb 09 '12 at 14:44
I've always used this approach. However, I've noticed that you do momentarily see the divider location in the wrong position before it is moved. To resolve this, rather then overriding paint(Graphics) I have taken to overriding validate() instead. – Adamski Jul 04 '12 at 11:46

score 2 · Answer 5 · answered May 09 '12 at 17:24

2

use setResizeWeight(double);

answered May 09 '12 at 17:24

alaster

3,821
3
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score 2 · Answer 6 · answered Dec 10 '09 at 07:22

2

If you're happy for the divider to move to the middle every time you resize the pane, you could add a ComponentListener and have its componentResized method call setDividerLocation(0.5).

answered Dec 10 '09 at 07:22

lins314159

2,510
1
16
19

3

You would use the setResizeWeight(...) method for this. – camickr Dec 10 '09 at 15:23

score 2 · Answer 7 · answered Aug 17 '15 at 19:22

2

I found the combination of setResizeWeight and setDividerLocation invoked later provides the behavior one would expect:

_splitPane.setResizeWeight(0.5);

SwingUtilities.invokeLater(new Runnable() {
    @Override
    public void run() {
        _splitPane.setDividerLocation(0.5);
    }
});

answered Aug 17 '15 at 19:22

Cord Rehn

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14
22

Because such operation **must** be done in EDT. – Matthieu Jan 21 '22 at 14:21

score 1 · Answer 8 · answered Feb 14 '12 at 19:00

This works for me, based on Dave Rays link.

/**
 * Set JSplitPane proportional divider location
 * 
 * @param jsplitpane JSplitPane to set
 * @param proportionalLocation double <0.0; 1.0>
 */
public static void setJSplitPaneDividerLocation(final JSplitPane jsplitpane, final double proportionalLocation)
{
    if (jsplitpane.isShowing())
    {
        if (jsplitpane.getWidth() > 0 && jsplitpane.getHeight() > 0)
        {
            jsplitpane.setDividerLocation(proportionalLocation);
        }
        else
        {
            jsplitpane.addComponentListener(new ComponentAdapter()
            {
                @Override
                public void componentResized(ComponentEvent ce)
                {
                    jsplitpane.removeComponentListener(this);
                    setJSplitPaneDividerLocation(jsplitpane, proportionalLocation);
                }
            });
        }
    }
    else
    {
        jsplitpane.addHierarchyListener(new HierarchyListener()
        {
            @Override
            public void hierarchyChanged(HierarchyEvent e)
            {
                if ((e.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0 && jsplitpane.isShowing())
                {
                    jsplitpane.removeHierarchyListener(this);
                    setJSplitPaneDividerLocation(jsplitpane, proportionalLocation);
                }
            }
        });
    }
}

score 0 · Answer 9 · edited Sep 27 '12 at 10:39

0

The following in the Component with the JSplitPane does it too:

@Override
public void setVisible(final boolean b) {
    super.setVisible(b);
    SwingUtilities.invokeLater(new Runnable() {

        @Override
        public void run() {
            AppFrame.this.jSplitPane.setDividerLocation(0.9d);
        }

    });
}

edited Sep 27 '12 at 10:39

Stephan

41,764
65
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answered Aug 01 '12 at 08:00

rodhel

1

Dave Ray · Answer 10 · 2011-06-14T20:07:09.147

0

There's a solution here that is a simple function that doesn't require sub-classing or any other changes to your splitpane.

edited Jun 14 '11 at 20:07

answered Jun 13 '11 at 00:07

Dave Ray

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7
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JSplitPane SetDividerLocation Problem

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