Question

I have a JFrame with a JSplitPane that is OneTouchExpandable.
I want to remember the last Divider position of the JSplitPane on JFrame dispose and restore the Position if the JFrame is reopened.

It works well, but if the User expand one Side via the oneTouchExpandable UI-Widget then
I store only the ‘int’-Position on dispose and set the ‘int’-Position back again with the consequence on JFrame-resizing the JSplitPane-Divider jumps to the collapsed Component preferredSize.

How can I get/set the collapse/expand State?

EDIT

Now: the resize-Behavior is OK, but it is not exactly the same behavior like the first-time-open – cause now I have no MinimumDividerLocation. I wanted the SnapIn but further the collapsedState.

public class SplitPaneState {
    public static void main( String[] args ) {
        SwingUtilities.invokeLater( new Runnable() {
            @Override
            public void run() {
                new SplitPaneState().createAndSowGUI();
            }
        });
    }

    private int position = -1;
    private Dimension size = new Dimension( 500, 300 );

    private void createAndSowGUI() {
        final JFrame frame = new JFrame("frame");
        frame.setSize( 200, 100 );
        frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        frame.setLocationRelativeTo( null );
        frame.getContentPane().add( new JButton( new AbstractAction(){
           {
               putValue( Action.NAME, "Open Dialog" );
           }
            @Override
            public void actionPerformed( ActionEvent e ) {
                final JSplitPane splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, new JLabel( "left Component" ), new JLabel( "right Component" ));
                splitPane.setContinuousLayout( true );
                splitPane.setOneTouchExpandable( true );
                if(position != -1) {
                    boolean LeftIsCollapsed = position < splitPane.getMinimumDividerLocation();
                    if(LeftIsCollapsed) {
                        splitPane.getLeftComponent().setMinimumSize(new Dimension()); // fix by Martijn Courteaux
                        splitPane.setDividerLocation(0.0d);                           // fix by Martijn Courteaux
                    }else {
                        splitPane.setDividerLocation(position);
                    }
                }
                JDialog dialog = new JDialog(frame,"dialog"){
                    @Override
                    public void dispose() {
                        position = splitPane.getDividerLocation();
                        size = this.getSize();
                        super.dispose();
                    }
                };
                dialog.setSize( size );
                dialog.setDefaultCloseOperation( JFrame.DISPOSE_ON_CLOSE );
                dialog.setLocationRelativeTo( frame );
                dialog.getContentPane().add( splitPane );
                dialog.setVisible( true );
                }
           }
       ));
       frame.setVisible( true );
    }
}

Answer 1

I found that it is possible to collapse one side of the splitpane by setting the minimum size of the component to new Dimension() and then set the divider location:

// Hide left or top
pane.getLeftComponent().setMinimumSize(new Dimension());
pane.setDividerLocation(0.0d);

// Hide right or bottom
pane.getRightComponent().setMinimumSize(new Dimension());
pane.setDividerLocation(1.0d);

You can play with these settings to store and restore the collapse/expand state.