如何在JFrame中更改字体颜色

Question

I want to change font color when I pressed button.

Font color is selected by 3 radiobuttons.

When I pressed button, then makeStyleSheet function makes a css.

In this css, only one color defined.

But font color doesn't changed....

Why ???

@SuppressWarnings("javadoc")
public class Sample extends JFrame {

    JRadioButton[] radio;
    JTextPane textPane;
    HTMLEditorKit kit;
    HTMLDocument doc;
    JButton btnNewButton;
    ButtonGroup group;
    List<JRadioButton> list;

    /**
     * @param args
     */
    public static void main(String[] args) {
        Sample frame = new Sample();
        ActionListener action = new MyButtonAction(frame.kit, frame.doc, frame.list);

        frame.addAction(action);
        frame.setVisible(true);
    }

    private void addAction(ActionListener action) {

        btnNewButton.addActionListener(action);
    }

    @SuppressWarnings("javadoc")
    public Sample() {

        doc = new HTMLDocument();
        textPane = new JTextPane();
        kit = new HTMLEditorKit();

        setBounds(100, 100, 450, 300);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        getContentPane().setLayout(null);

       textPane.setEditorKit(kit);
       textPane.setDocument(doc);
        textPane.setContentType("text/html");
        textPane.setBounds(12, 13, 282, 229);
        getContentPane().add(textPane);

        btnNewButton = new JButton("HTML");
        btnNewButton.setBounds(303, 211, 117, 31);

        getContentPane().add(btnNewButton);

        group = new ButtonGroup();

        list = new ArrayList<JRadioButton>();

       JRadioButton rdbtnRed = new JRadioButton("apple", true);
        JRadioButton rdbtnYellow = new JRadioButton("banana");
        JRadioButton rdbtnGreen = new JRadioButton("mellon");

       list.add(rdbtnRed);
       list.add(rdbtnYellow);
      list.add(rdbtnGreen);

       group.add(rdbtnRed);
       group.add(rdbtnYellow);
        group.add(rdbtnGreen);

        rdbtnRed.setBounds(302, 161, 113, 21);
        getContentPane().add(rdbtnRed);
        rdbtnYellow.setBounds(302, 138, 113, 21);
        getContentPane().add(rdbtnYellow);
        rdbtnGreen.setBounds(302, 115, 113, 21);
        getContentPane().add(rdbtnGreen);
    }
}

class MyButtonAction implements ActionListener {

    HTMLEditorKit kit;
        HTMLDocument doc;
        List<JRadioButton> list;

    public MyButtonAction(HTMLEditorKit kit, HTMLDocument doc, List<JRadioButton> list) {

        this.kit = kit;
        this.doc = doc;
        this.list = list;
    }

    @Override
    public void actionPerformed(ActionEvent e) {

        String tag = null;

        for(JRadioButton btn : list) {

            if (btn.isSelected()){

                tag = btn.getText();
            }
        }

        kit.setStyleSheet(makeStyleSheet(tag));

        try {

            kit.insertHTML(doc, doc.getLength(), "<font class=\"apple\">apple</font>,<font class=\"banana\">banana</font>,<font class=\"mellon\">mellon</font>", 0, 0, null);
        } catch (IOException e1) {

            e1.printStackTrace();
        } catch (BadLocationException e1) {

            e1.printStackTrace();
        }
    }

    private StyleSheet makeStyleSheet(String tag) {

        StyleSheet styleSheet = new StyleSheet();
        styleSheet.addRule("." + tag + " {color: red;}");

        return styleSheet;
    }
}

Answer 1

Add the CSS rules to the stylesheet of the doc , not kit .

    doc.getStyleSheet().addRule(".apple {color: red;}");
    doc.getStyleSheet().addRule(".banana {color: yellow;}");
    doc.getStyleSheet().addRule(".mellon {color: green;}");

By the way: more regular is to use a <span> io a <font> .

Answer 2

You can use setFont method like:

.setFont(new Font("Sans Serif", Font.PLAIN, 75));

For more details please click here

Answer 3

If you desire to change the font color of components with text you can simply change their foregroundColor. Here is a demonstration that changes the font color every 200 seconds.

JFrame frame = new JFrame();
        final JTextPane pane = new JTextPane();
        final JButton button = new JButton("HELLO");
        pane.setText("HELLO");
        frame.getContentPane().add(pane);

        new javax.swing.Timer(200, new ActionListener() {
            Random random = new Random();
            @Override
            public void actionPerformed(ActionEvent arg0) {
                Color color = new Color(random.nextInt(256),
                        random.nextInt(256), random.nextInt(256));
                pane.setForeground(color); //<== change text color ==>
            }
        }).start();
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);

Answer 4

You can also use java.awt.Color to color the font.

If you are using a JLabel , then .setForeground(Color.X) ; will change the color of the text. For example, .setForeground(Color.WHITE) will change the color of my JLabel to white.