Resizing variable size panel with JScrollPane

Question

I have a JPanel which contains four radio buttons. Selecting each of them opens another panel which are of different sizes.
These panels open in the same parent panel below the radio button panel.
However these panels contain large no of components. i.e. the final size of the main panel varies depeding on which button is selected.
I am using a JScrollPane to view them properly.
However, I am facing problem while resizing the main panel. If I mention the preferred size of the JScrollPane, the main panel on maximizing, shows this scrollpane with the size mentioned and does not get maximized as the parent panel.
If I don't mention the scrollpane size, resizing the main panel don't show the scrollbars.
what is the correct way to implement a JScrollpane in this case?
Also can anyone tell me what is the exact deifference between setSize() and setPreferredSize()?

Answer 1

i think you are looking for this if i got it right.
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ButtonGroup;
import javax.swing.ComboBoxModel;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JScrollPane;
import javax.swing.JToggleButton;
import javax.swing.WindowConstants;
public class TestVariablePanelSize extends javax.swing.JPanel
    private JPanel buttonPanel;
    private JRadioButton jRadioButton3;
    private JRadioButton jRadioButton4;
    private JLabel jLabel3;
    private JPanel displayPanel2;
    private JLabel jLabel2;
    private JLabel jLabel1;
    private JPanel jPanel1;
    private ButtonGroup buttonGroup1;
    private JScrollPane jScrollPane1;
    private JToggleButton jToggleButton1;
    private JComboBox jComboBox1;
    private JPanel topPanel;
    private JPanel displayPanel;
    private JPanel parentPanel;
    private JRadioButton jRadioButton2;
    private JRadioButton jRadioButton1;
    JFrame container;
    public static void main(String[] args)
        JFrame frame = new JFrame();
        frame.getContentPane().add(new TestVariablePanelSize(frame));
        frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    public TestVariablePanelSize(JFrame frame)
        super();
        container = frame;
        initGUI();
    private void initGUI()
        try
            Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
            System.out.println("screenSize" + screenSize);
            container.setMaximumSize(screenSize);
            final ErrorReportImportPanel errorReportPanel = new ErrorReportImportPanel();
            BorderLayout thisLayout = new BorderLayout();
            container.setLayout(thisLayout);
            container.setPreferredSize(new java.awt.Dimension(655, 365));
            container.setFocusable(false);
            // START >> jScrollPane1
            // START >>
            buttonGroup1 = new ButtonGroup();
            // END << buttonGroup1
            jScrollPane1 = new JScrollPane();
            container.add(jScrollPane1, BorderLayout.NORTH);
            jScrollPane1.setPreferredSize(new java.awt.Dimension(602, 285));
            // START >> parentPanel
            parentPanel = new JPanel();
            jScrollPane1.setViewportView(parentPanel);
            GridBagLayout parentPanelLayout = new GridBagLayout();
            parentPanelLayout.columnWeights = new double[]{0.1};
            parentPanelLayout.columnWidths = new int[]{7};
            parentPanelLayout.rowWeights = new double[]{0.0, 0.0, 0.0, 0.0};
            parentPanelLayout.rowHeights = new int[]{33, 23, 186, 26};
            parentPanel.setLayout(parentPanelLayout);
            // parentPanel.setPreferredSize(new java.awt.Dimension(652, 371));
            // START >> topPanel
            topPanel = new JPanel();
            parentPanel.add(topPanel, new GridBagConstraints(
                0,
                0,
                1,
                1,
                0.0,
                0.0,
                GridBagConstraints.NORTH,
                GridBagConstraints.NONE,
                new Insets(0, 0, 0, 0),
                0,
                0));
            // START >> jComboBox1
            ComboBoxModel jComboBox1Model = new DefaultComboBoxModel(new String[]{"Item One", "Item Two"});
            jComboBox1 = new JComboBox();
            topPanel.add(jComboBox1);
            jComboBox1.setModel(jComboBox1Model);
            jComboBox1.setPreferredSize(new java.awt.Dimension(75, 20));
            // END << jComboBox1
            // END << topPanel
            // START >> buttonPanel
            buttonPanel = new JPanel();
            parentPanel.add(buttonPanel, new GridBagConstraints(
                0,
                1,
                1,
                1,
                0.0,
                0.0,
                GridBagConstraints.NORTH,
                GridBagConstraints.NONE,
                new Insets(0, 0, 0, 0),
                0,
                0));
            // START >> jRadioButton1
            jRadioButton1 = new JRadioButton();
            buttonPanel.add(jRadioButton1);
            jRadioButton1.setText("jRadioButton1");
            jRadioButton1.addActionListener(new ActionListener()
                public void actionPerformed(ActionEvent evt)
                    displayPanel.setVisible(true);
                    // displayPanel2.setVisible(false);
                    // parentPanel.remove(displayPanel2);
            // END << jRadioButton1
            // START >> jRadioButton2
            jRadioButton2 = new JRadioButton();
            buttonPanel.add(jRadioButton2);
            jRadioButton2.setText("jRadioButton2");
            jRadioButton2.addActionListener(new ActionListener()
                public void actionPerformed(ActionEvent evt)
                    displayPanel2.setVisible(true);
                    displayPanel.setVisible(false);
                    parentPanel.remove(displayPanel2);
            // END << jRadioButton2
            // START >> jRadioButton3
            jRadioButton3 = new JRadioButton();
            buttonPanel.add(jRadioButton3);
            jRadioButton3.setText("jRadioButton3");
            // END << jRadioButton3
            // START >> jRadioButton4
            jRadioButton4 = new JRadioButton();
            buttonPanel.add(jRadioButton4);
            jRadioButton4.setText("jRadioButton4");
            // END << jRadioButton4
            // END << buttonPanel
            buttonGroup1.add(jRadioButton1);
            buttonGroup1.add(jRadioButton2);
            buttonGroup1.add(jRadioButton3);
            buttonGroup1.add(jRadioButton4);
            // START >> displayPanel
            displayPanel = new JPanel();
            parentPanel.add(displayPanel, new GridBagConstraints(
                0,
                2,
                1,
                1,
                0.0,
                0.0,
                GridBagConstraints.NORTH,
                GridBagConstraints.BOTH,
                new Insets(0, 0, 0, 0),
                0,
                0));
            displayPanel.setVisible(false);
            // START >> jLabel2
            jLabel2 = new JLabel();
            displayPanel.add(jLabel2);
            jLabel2.setText("displayPanel");
            jLabel2.setPreferredSize(new java.awt.Dimension(462, 152));
            jLabel2.setOpaque(true);
            jLabel2.setBackground(new java.awt.Color(128, 128, 255));
            jLabel2.setVisible(false);
            // END << jLabel2
            // END << displayPanel
            // START >> displayPanel2
            displayPanel2 = new JPanel();
            parentPanel.add(displayPanel2, new GridBagConstraints(
                0,
                2,
                1,
                1,
                0.0,
                0.0,
                GridBagConstraints.CENTER,
                GridBagConstraints.BOTH,
                new Insets(0, 0, 0, 0),
                0,
                0));
            displayPanel2.setVisible(false);
            // START >> jLabel3
            jLabel3 = new JLabel();
            displayPanel2.add(jLabel3);
            jLabel3.setText("displayPanel2");
            jLabel3.setOpaque(true);
            jLabel3.setBackground(new java.awt.Color(0, 128, 192));
            jLabel3.setPreferredSize(new java.awt.Dimension(460, 171));
            // END << jLabel3
            // END << displayPanel2
            // START >> jToggleButton1
            jToggleButton1 = new JToggleButton();
            parentPanel.add(jToggleButton1, new GridBagConstraints(
                0,
                3,
                1,
                1,
                0.0,
                0.0,
                GridBagConstraints.WEST,
                GridBagConstraints.NONE,
                new Insets(0, 0, 0, 0),
                0,
                0));
            jToggleButton1.setText("jToggleButton1");
            // END << jToggleButton1
            // START >> jPanel1
            jPanel1 = new JPanel();
            parentPanel.add(jPanel1, new GridBagConstraints(
                0,
                4,
                1,
                1,
                0.0,
                0.0,
                GridBagConstraints.CENTER,
                GridBagConstraints.NONE,
                new Insets(0, 0, 0, 0),
                0,
                0));
            // START >> jLabel1
            jLabel1 = new JLabel();
            jPanel1.add(jLabel1);
            jLabel1.setText("Another Panel");
            jLabel1.setPreferredSize(new java.awt.Dimension(469, 87));
            jLabel1.setBackground(new java.awt.Color(0, 128, 0));
            jLabel1.setForeground(new java.awt.Color(0, 0, 0));
            jLabel1.setOpaque(true);
            // END << jLabel1
            // END << jPanel1
            // END << parentPanel
            // END << jScrollPane1
        catch (Exception e)
            e.printStackTrace();
}