Change Font at runtime

Question

Please is there another way how to change Font at runtime as using FontUIResource, for the whole AWT/Swing GUI, without any knowledge / interest about if there are local variables and type of JComponents

import java.awt.*;
import java.awt.event.*;
import java.util.Locale;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.*;
import javax.swing.plaf.FontUIResource;
import javax.swing.plaf.basic.BasicComboBoxRenderer;

public class SystemFontDisplayer extends JFrame {

    private static final long serialVersionUID = 1L;
    private JFrame frame = new JFrame("Nimbus UIDeafaults and Font");
    private JComboBox fontsBox;
    private javax.swing.Timer timer = null;
    private JButton testButton = new JButton("testButton");
    private JTextField testTextField = new JTextField("testTextField");
    private JLabel testLabel = new JLabel("testLabel");

    public SystemFontDisplayer() {
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        String[] fontFamilyNames = ge.getAvailableFontFamilyNames(Locale.getDefault());
        fontsBox = new JComboBox(fontFamilyNames);
        fontsBox.setSelectedItem(0);
        fontsBox.setRenderer(new ComboRenderer());
        fontsBox.addItemListener(new ItemListener() {

            @Override
            public void itemStateChanged(ItemEvent e) {
                if (e.getStateChange() == ItemEvent.SELECTED) {
                    final String fontName = fontsBox.getSelectedItem().toString();
                    fontsBox.setFont(new Font(fontName, Font.PLAIN, 16));
                    start();
                }
            }
        });
        fontsBox.setSelectedItem(0);
        fontsBox.getEditor().selectAll();
        frame.setLayout(new GridLayout(4, 0, 20, 20));
        frame.add(fontsBox);
        frame.add(testButton);
        frame.add(testTextField);
        frame.add(testLabel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocation(200, 105);
        frame.pack();
        java.awt.EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                fontsBox.setPopupVisible(true);
                fontsBox.setPopupVisible(false);
            }
        });
        frame.setVisible(true);
    }

    private void start() {
        timer = new javax.swing.Timer(750, updateCol());
        timer.setRepeats(false);
        timer.start();
    }

    public Action updateCol() {
        return new AbstractAction("text load action") {

            private static final long serialVersionUID = 1L;

            @Override
            public void actionPerformed(ActionEvent e) {
                final Font fnt = new Font(fontsBox.getSelectedItem().toString(), Font.PLAIN, 12);
                /*try {
                    LookAndFeel lnf = UIManager.getLookAndFeel().getClass().newInstance();
                    final FontUIResource res = new FontUIResource(fnt);
                    UIDefaults uiDefaults = lnf.getDefaults();
                    uiDefaults.put("Button.font", res);
                    uiDefaults.put("TextField.font", res);
                    uiDefaults.put("Label.font", res);
                    UIManager.getLookAndFeel().uninitialize();
                    UIManager.setLookAndFeel(lnf);
                } catch (InstantiationException ex) {
                    Logger.getLogger(SystemFontDisplayer.class.getName()).log(Level.SEVERE, null, ex);
                } catch (IllegalAccessException ex) {
                    Logger.getLogger(SystemFontDisplayer.class.getName()).log(Level.SEVERE, null, ex);
                } catch (UnsupportedLookAndFeelException ex) {
                    Logger.getLogger(SystemFontDisplayer.class.getName()).log(Level.SEVERE, null, ex);
                }
                UIDefaults defaults = UIManager.getDefaults();
                final FontUIResource res = new FontUIResource(fnt);
                defaults.put("Button.font", res);
                defaults.put("TextField.font", res);
                defaults.put("Label.font", res);
                SwingUtilities.updateComponentTreeUI(frame);*/
                final FontUIResource res = new FontUIResource(fnt);
                UIManager.getLookAndFeelDefaults().put("Button.font", res);
                UIManager.getLookAndFeelDefaults().put("TextField.font", res);
                UIManager.getLookAndFeelDefaults().put("Label.font", res);
                SwingUtilities.updateComponentTreeUI(frame);
            }
        };
    }

    public static void main(String arg[]) {
        /*try {
            for (UIManager.LookAndFeelInfo laf : UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(laf.getName())) {
                    UIManager.setLookAndFeel(laf.getClassName());
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }*/
        java.awt.EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                SystemFontDisplayer systemFontDisplayer = new SystemFontDisplayer();
            }
        });
    }

    private class ComboRenderer extends BasicComboBoxRenderer {

        private static final long serialVersionUID = 1L;

        @Override
        public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
            super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
            final Object fntObj = value;
            final String fontFamilyName = (String) fntObj;
            setFont(new Font(fontFamilyName, Font.PLAIN, 16));
            return this;
        }
    }
}

.

EDIT: I posted narrative with Nimbus, then code for Nimbus

import java.awt.*;
import java.awt.event.*;
import java.util.Locale;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.*;
import javax.swing.plaf.FontUIResource;
import javax.swing.plaf.basic.BasicComboBoxRenderer;

public class SystemFontDisplayer extends JFrame {

    private static final long serialVersionUID = 1L;
    private JFrame frame = new JFrame("Nimbus UIDeafaults and Font");
    private JComboBox fontsBox;
    private javax.swing.Timer timer = null;
    private JButton testButton = new JButton("testButton");
    private JTextField testTextField = new JTextField("testTextField");
    private JLabel testLabel = new JLabel("testLabel");

    public SystemFontDisplayer() {
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        String[] fontFamilyNames = ge.getAvailableFontFamilyNames(Locale.getDefault());
        fontsBox = new JComboBox(fontFamilyNames);
        fontsBox.setSelectedItem(0);
        fontsBox.setRenderer(new ComboRenderer());
        fontsBox.addItemListener(new ItemListener() {

            @Override
            public void itemStateChanged(ItemEvent e) {
                if (e.getStateChange() == ItemEvent.SELECTED) {
                    final String fontName = fontsBox.getSelectedItem().toString();
                    fontsBox.setFont(new Font(fontName, Font.PLAIN, 16));
                    start();
                }
            }
        });
        fontsBox.setSelectedItem(0);
        fontsBox.getEditor().selectAll();
        frame.setLayout(new GridLayout(4, 0, 20, 20));
        frame.add(fontsBox);
        frame.add(testButton);
        frame.add(testTextField);
        frame.add(testLabel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocation(200, 105);
        frame.pack();
        java.awt.EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                fontsBox.setPopupVisible(true);
                fontsBox.setPopupVisible(false);
            }
        });
        frame.setVisible(true);
    }

    private void start() {
        timer = new javax.swing.Timer(750, updateCol());
        timer.setRepeats(false);
        timer.start();
    }

    public Action updateCol() {
        return new AbstractAction("text load action") {

            private static final long serialVersionUID = 1L;

            @Override
            public void actionPerformed(ActionEvent e) {
                final Font fnt = new Font(fontsBox.getSelectedItem().toString(), Font.PLAIN, 12);
                try {
                    LookAndFeel lnf = UIManager.getLookAndFeel().getClass().newInstance();
                    final FontUIResource res = new FontUIResource(fnt);
                    UIDefaults uiDefaults = lnf.getDefaults();
                    uiDefaults.put("Button.font", res);
                    uiDefaults.put("TextField.font", res);
                    uiDefaults.put("Label.font", res);
                    UIManager.getLookAndFeel().uninitialize();
                    UIManager.setLookAndFeel(lnf);
                } catch (InstantiationException ex) {
                    Logger.getLogger(SystemFontDisplayer.class.getName()).log(Level.SEVERE, null, ex);
                } catch (IllegalAccessException ex) {
                    Logger.getLogger(SystemFontDisplayer.class.getName()).log(Level.SEVERE, null, ex);
                } catch (UnsupportedLookAndFeelException ex) {
                    Logger.getLogger(SystemFontDisplayer.class.getName()).log(Level.SEVERE, null, ex);
                }
                UIDefaults defaults = UIManager.getDefaults();
                final FontUIResource res = new FontUIResource(fnt);
                defaults.put("Button.font", res);
                defaults.put("TextField.font", res);
                defaults.put("Label.font", res);
                SwingUtilities.updateComponentTreeUI(frame);
                /*final FontUIResource res = new FontUIResource(fnt);
                UIManager.getLookAndFeelDefaults().put("Button.font", res);
                UIManager.getLookAndFeelDefaults().put("TextField.font", res);
                UIManager.getLookAndFeelDefaults().put("Label.font", res);
                SwingUtilities.updateComponentTreeUI(frame);*/
            }
        };
    }

    public static void main(String arg[]) {
        try {
            for (UIManager.LookAndFeelInfo laf : UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(laf.getName())) {
                    UIManager.setLookAndFeel(laf.getClassName());
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        java.awt.EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                SystemFontDisplayer systemFontDisplayer = new SystemFontDisplayer();
            }
        });
    }

    private class ComboRenderer extends BasicComboBoxRenderer {

        private static final long serialVersionUID = 1L;

        @Override
        public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
            super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
            final Object fntObj = value;
            final String fontFamilyName = (String) fntObj;
            setFont(new Font(fontFamilyName, Font.PLAIN, 16));
            return this;
        }
    }
}

Catarina

+1 for sscce; see also FontShower. – Crowfoot

Minor notes: Only need one instance of javax.swing.Timer; only need one setSelectedItem(); consider getAvailableFontFamilyNames(Locale.getDefault()). Works on Mac OS. – Crowfoot

@Crowfoot sure again part of my useless balasts, previously I have auto_select for JComboBox from Timer and then change Font by value from JComboBox's selectedItem, I'm sorry for that – Catarina

Update looks good; manItemInCombo() looks handy, too. – Crowfoot

@Crowfoot I know that maybe, aaaach I surmise that this was already a bold risk ... – Catarina

What is the problem with FontUIRessource? – Kugler

@user unknown no issues, nor problem, only nobody to knows when, where you needed an alternative – Catarina

Answer 1

For instance: Create a new Font from the FontFamily list, and apply it to your component with c.setFont (font);

A second approach is, to search for TTF-Files (for example), and create new Fonts with the static method Font.createFont (new File ("..."));

This simple app will create a List of Fonts by family, and apply it to a JButton and JTextField.

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
/**
    FontSwitcher

    @author Stefan Wagner
    @date So 13. Mai 03:25:23 CEST 2012    
*/
public class FontSwitcher extends JFrame implements ActionListener
{
    private static final String progname = "FontSwitcher 0.1";

    private JTextField feedback;
    private JButton jb;
    private JList fontList;

    public FontSwitcher ()
    {
        super (progname);
        JPanel mainpanel = new JPanel ();
        mainpanel.setLayout (new BorderLayout ());
        this.getContentPane ().add (mainpanel);

        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment ();
        String [] fonts = ge.getAvailableFontFamilyNames ();
        fontList = new JList (fonts);
        JScrollPane js = new JScrollPane (fontList);

        feedback = new JTextField ("Feedback");
        jb = new JButton ("apply font");
        jb.addActionListener (this);
        mainpanel.add (feedback, BorderLayout.NORTH);
        mainpanel.add (js, BorderLayout.CENTER);
        mainpanel.add (jb, BorderLayout.SOUTH);

        setSize (400, 800);
        setLocation (100, 100);
        setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
        setVisible (true);
    }

    public void actionPerformed (final ActionEvent e)
    {
        SwingWorker worker = new SwingWorker () 
        {
            protected String doInBackground () throws InterruptedException 
            {
                String cmd = e.getActionCommand ();
                if (cmd.equals ("apply font"))
                {
                    String selectedFont = fontList.getSelectedValue ().toString ();
                    Font font = new Font (selectedFont, Font.TRUETYPE_FONT, 14);
                    jb.setFont (font);
                    feedback.setFont (font);
                }
                return "done";
            }
            protected void done () 
            {
                feedback.setText ("done");
            }
        };
        worker.execute ();
    }

    public static void main (final String args[])
    {
        Runnable runner = new Runnable () 
        {
            public void run () 
            {
                new FontSwitcher ();
            }
        };
        EventQueue.invokeLater (runner);
    }
}

Kugler

aaach now I see that my question isn't correctly asked, sure I miss there for the whole AWT/Swing GUI, without any interest about local variable, danke – Catarina

@mKorbel: I'm sorry, I'm not sure if I understand. You're only interested in switching the whole look, the fonts for all components - not individually? And you're looking for a second approach, only from pure interest - not with a specific problem you can't solve? Have you searched for "LookAndFeel"? I read something about it years ago, but didn't investigate it. I think it is about switching the whole look and feel of an application, and should change the fonts too. – Kugler

Another idea would be a visitor, which traverses your whole GUI-Tree (don't know how hard it is) and applys some font everywhere. – Kugler

I haven't any issue, nor with various Look and Feels (after Substance L&F), ComponentTree could be another way – Catarina