在Java Swing JTextComponent中突出显示更改的文本

Question

I am trying to highlight some code in a JEditorPane like this:

import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.text.DefaultHighlighter;
import javax.swing.text.Highlighter;

public class Driver
{
    public static void main(String[] args)
    {
        try
        {
            //create a simple frame with an editor pane
            JFrame frame = new JFrame("Highlight Test");
            JEditorPane pane = new JEditorPane();
            frame.getContentPane().add(pane);
            frame.setSize(300, 300);
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setVisible(true);

            //string to put in the pane
            String text = "1234567890";

            //grab the highlighter for the pane
            Highlighter highlighter = pane.getHighlighter();

            //store all the text at once
            pane.setText(text);

            //go through all the characters
            for(int i = 0; i < text.length(); i++)
            {
                //highlight the latest character
                highlighter.addHighlight(i, i + 1, DefaultHighlighter.DefaultPainter);

                //sleep for a quarter second
                Thread.sleep(250);
            }
        }catch(Exception ex){}
    }

}

This will highlight the characters one at a time and all the characters will remain highlighted. Now, I'd like the same behavior (all the characters remain highlighted) but I'd like to change the text in between highlights, like this:

import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.text.DefaultHighlighter;
import javax.swing.text.Highlighter;

public class Driver
{
    public static void main(String[] args)
    {
        try
        {
            //create a simple frame with an editor pane
            JFrame frame = new JFrame("Highlight Test");
            JEditorPane pane = new JEditorPane();
            frame.getContentPane().add(pane);
            frame.setSize(300, 300);
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setVisible(true);

            //string to put in the pane
            String text = "1234567890";

            //grab the highlighter for the pane
            Highlighter highlighter = pane.getHighlighter();

            //go through all the characters
            for(int i = 0; i < text.length(); i++)
            {
                //place a new string in the pane
                pane.setText(pane.getText() + text.charAt(i));

                //highlight the latest character
                highlighter.addHighlight(i, i + 1, DefaultHighlighter.DefaultPainter);

                //sleep for a quarter second
                Thread.sleep(250);
            }
        }catch(Exception ex){}
    }

}

Notice the text in the pane is changing and then I'm applying a new highlight. The old highlights go away- I'd like them to stay. My assumption is the highlights go away each time you setText(). So, is there any way to keep the highlights in the text component while changing the text?

Answer 1

i didn't tried the following code but what i suggest is just try to highlight both latest character and previous ones too like this:

        //go through all the characters
        for(int i = 0; i < text.length(); i++)
        {
            //place a new string in the pane
            pane.setText(pane.getText() + text.charAt(i));
          //highlight the previous characters
          if (i > 0) {
           for ( int j=i-1; j >= 0; j--)
             highlighter.addHighlight(j, j+1 , DefaultHighlighter.DefaultPainter);
           }
            //highlight the latest character
            highlighter.addHighlight(i, i + 1, DefaultHighlighter.DefaultPainter);

            //sleep for a quarter second
           // Thread.sleep(250);
        }
    }catch(Exception ex){}