Highlight current row in JTextPane

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别那么骄傲
别那么骄傲 2021-02-08 21:21

I\'m trying for more than 2 days to implement a specific requirement for a text editor window... unfortunately without success so far :(

The goal is to get a text editor

3条回答
  •  悲哀的现实
    2021-02-08 21:32

    I think this might be difficult to achieve using highlighters - I don't think it is what they were designed for. You may need to do it with custom painting code:

    import java.awt.Color;
    import java.awt.Graphics;
    import java.awt.Rectangle;
    
    import javax.swing.JFrame;
    import javax.swing.JTextPane;
    import javax.swing.text.BadLocationException;
    
    public class HighlightLineTest {
        private static class HighlightLineTextPane extends JTextPane {
            public HighlightLineTextPane() {
                // Has to be marked as transparent so the background is not replaced by 
                // super.paintComponent(g);
                setOpaque(false);
            }
    
            @Override
            protected void paintComponent(Graphics g) {
                g.setColor(getBackground());
                g.fillRect(0, 0, getWidth(), getHeight());
                try {
                    Rectangle rect = modelToView(getCaretPosition());
                    if (rect != null) {
                        g.setColor(Color.CYAN);
                        g.fillRect(0, rect.y, getWidth(), rect.height);
                    }
                } catch (BadLocationException e) {
                }
                super.paintComponent(g);
            }
    
            @Override
            public void repaint(long tm, int x, int y, int width, int height) {
                // This forces repaints to repaint the entire TextPane.
                super.repaint(tm, 0, 0, getWidth(), getHeight());
            }
        }
    
        public static void main(String[] args) {
            JFrame frame = new JFrame("Highlight test");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.add(new HighlightLineTextPane());
            frame.setBounds(100, 100, 300, 400);
            frame.setVisible(true);
        }
    }
    

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