How to update LookAndFeel in Java?

Question

I have written a program that updates the LookAndFeel on a test GUI first. Once the user clicks the "select" button, the LookAndFeel is passed to a main GUI method that creates a new window using that selection.

It works fine. Although, as the user cycles through the various LookAndFeels, the test GUI does not really update and show the changes. Each time the change button is clicked I have it update and display the current LookAndFeel(and repain();), so I know it is changing. Also, when you hit select, the new GUI is created using whatever option you were on at the time(even though the test GUI window was not showing the changes).

What am I doing wrong?

    import javax.swing.*;           //UI.Manager <-- available
    import java.awt.*;
    import java.awt.event.*;
    import javax.swing.UIManager.*;
    import javax.imageio.ImageIO;
    import java.io.IOException;
    import java.net.URL;

    public class gui1 {
    static JFrame frame1, testFrame;
    static Container pane, testPane;
    static JButton btnConnect, btnDisconnect, changeButton, selectButton;
    static JLabel lblServer, lblUsername, lblPassword, lblPort, testLabel;
    static JTextField txtServer, txtUsername, txtPassword, txtPort;
    static Insets insets;
    static JTextArea area, testArea;
    public JScrollPane scroller, testScroller;
    static int  currentIndex;


URL frameImage;
Image img;

static boolean LookAndFeelSelected;

public static void main(String[] args){
    gui1 begin = new gui1();
}

public gui1() {

    //build our test gui & components
    testFrame = new JFrame("Select which LookAndFeel you prefer..");
    testFrame.setSize(375, 250);
    testFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    testLabel = new JLabel("Text Example", JLabel.CENTER);
    testArea = new JTextArea(300,200);
    testPane = testFrame.getContentPane();
    changeButton = new JButton("Change");
    selectButton = new JButton("Select");
    testScroller = new JScrollPane(testArea);
    testScroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
    testScroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);

    testPane.add(changeButton);
    testPane.add(selectButton);
    testFrame.getContentPane().add(BorderLayout.WEST, changeButton);
    testFrame.getContentPane().add(BorderLayout.EAST, selectButton);
    testFrame.getContentPane().add(BorderLayout.CENTER, testScroller);
    testFrame.getContentPane().add(BorderLayout.NORTH, testLabel);

    changeButton.addActionListener(new changeListener());
    selectButton.addActionListener(new selectListener());

    testFrame.setVisible(true);

    while(!LookAndFeelSelected) {
        try{
            Thread.sleep(500);
        }catch(InterruptedException ex) {ex.printStackTrace();}
    }

    System.out.println("Selected!");
    //start the real GUI with selected LookAndFeel
    testFrame.dispose();
    buildGui(UIManager.getLookAndFeel());
}
public void buildGui(LookAndFeel chosen){
    //The frame and panel
    frame1 = new JFrame("Sample GUI Application");
    frame1.setSize(800, 230);
    frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    pane = frame1.getContentPane();
    pane.setLayout(null);
    insets = pane.getInsets();

    //Set the image
    try{
        frameImage = new URL("http://i.imgur.com/jMaYO1f.jpg");
        img = ImageIO.read(frameImage);
    }catch(IOException ex){ex.printStackTrace();}
    frame1.setIconImage(img);

    //Construct our objects for gui
    btnConnect = new JButton("Connect");
    btnDisconnect = new JButton("Disconnect");
    lblServer = new JLabel("Remote Host: ");
    lblUsername = new JLabel("Username: ");
    lblPassword = new JLabel("Password: ");
    lblPort = new JLabel("Port #");
    txtServer = new JTextField(10);
    txtPassword = new JTextField(10);
    txtUsername = new JTextField(10);
    txtPort = new JTextField(5);
    area = new JTextArea(700, 125);
    area.setLineWrap(true);
    area.setEditable(false);
    scroller = new JScrollPane(area);
    scroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
    scroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);

    //Add components to the pane
    pane.add(lblServer);
    pane.add(lblServer);
    pane.add(lblPassword);
    pane.add(lblUsername);
    pane.add(lblPort);
    pane.add(txtServer);
    pane.add(txtPort);
    pane.add(txtPassword);
    pane.add(txtUsername);
    pane.add(btnConnect);
    pane.add(btnDisconnect);
    pane.add(scroller);  //includes area and scroller!


    //Arrange our components in the pane
    lblServer.setBounds(insets.left + 5, insets.top + 5, lblServer.getPreferredSize().width, lblServer.getPreferredSize().height);
    txtServer.setBounds(lblServer.getX() + lblServer.getWidth() + 5, insets.top + 5, txtServer.getPreferredSize().width, txtServer.getPreferredSize().height);
    lblUsername.setBounds(txtServer.getX() + txtServer.getWidth() + 5, insets.top + 5, lblUsername.getPreferredSize().width, lblUsername.getPreferredSize().height);
    txtUsername.setBounds(lblUsername.getX() + lblUsername.getWidth() + 5, insets.top + 5, txtUsername.getPreferredSize().width, txtUsername.getPreferredSize().height);
    lblPassword.setBounds(txtUsername.getX() + txtUsername.getWidth() + 5, insets.top + 5, lblPassword.getPreferredSize().width, lblPassword.getPreferredSize().height);
    txtPassword.setBounds(lblPassword.getX() + lblPassword.getWidth() + 5, insets.top + 5, txtPassword.getPreferredSize().width, txtPassword.getPreferredSize().height);
    lblPort.setBounds(txtPassword.getX() + txtPassword.getWidth() + 5, insets.top + 5, lblPort.getPreferredSize().width, lblPort.getPreferredSize().height);
    txtPort.setBounds(lblPort.getX() + lblPort.getWidth() + 5, insets.top + 5, txtPort.getPreferredSize().width, txtPort.getPreferredSize().height);
    btnConnect.setBounds(txtPort.getX() + txtPort.getWidth() + 5, insets.top + 5, btnConnect.getPreferredSize().width, btnConnect.getPreferredSize().height);
    btnDisconnect.setBounds(insets.left + 5, lblServer.getY() + lblServer.getHeight() + 15, btnDisconnect.getPreferredSize().width, btnDisconnect.getPreferredSize().height);
    scroller.setBounds(insets.left + 5, btnDisconnect.getX() + btnDisconnect.getHeight() + 33, 760, 125);

    //Add button listeners
    btnConnect.addActionListener(new connectListener());
    btnDisconnect.addActionListener(new disconnectListener());

    //Change the Look & Feel
    try {
        UIManager.setLookAndFeel(chosen);
    } catch (Exception ex) {ex.printStackTrace();}

    frame1.setVisible(true);
    frame1.setResizable(false);
}


public static class connectListener implements ActionListener {
    public void actionPerformed(ActionEvent event){
        String toField = String.format("ServerIP: %s \t Username: %s \t Password: %s \t Port: %s\n", txtServer.getText(), txtUsername.getText(),
                txtPassword.getText(), txtPort.getText());
        area.append(toField);
    }
}

public static class disconnectListener implements ActionListener {
    public void actionPerformed(ActionEvent event){
        area.append("Disconnected ..\n");
    }
}
// Here only for initial LookAndFeel selection!
public static class changeListener implements ActionListener {
    public void actionPerformed(ActionEvent event){
        LookAndFeelInfo[] lafArray = UIManager.getInstalledLookAndFeels();  //not actual LookAndFeel(just name), thus use LookAndFeelInfo

        try {
            if (currentIndex == lafArray.length - 1) {
                currentIndex = 0;
                System.out.println("You have seen all Look and Feels, starting over .. \n\n");
            }
            UIManager.setLookAndFeel(lafArray[currentIndex++].getClassName());
            testFrame.getContentPane().validate();
            testFrame.getContentPane().repaint();    //repaint the frame to update changes

        }catch(Exception ex) {ex.printStackTrace();}
        String LookAndFeelName = String.format("Changed to: %s",UIManager.getLookAndFeel().getClass());     //gets current and displays name
        System.out.println(LookAndFeelName);
    }
}

public static class selectListener implements ActionListener {
    public void actionPerformed(ActionEvent event){
        LookAndFeelSelected = true;
    }
}

}

Answer 1

This isnt a repainting issue, The look and feel goes deeper than just painting colors. Look at this tutorial http://www.roseindia.net/java/example/java/swing/GettingAndSettingLAF.shtml

below where you change your look and feel on button click change:

testFrame.getContentPane().validate();
testFrame.getContentPane().repaint();

to

SwingUtilities.updateComponentTreeUI(testFrame);