java - Set hilighting color in jTextField

Question

I am developing a Java Swing application. This app allows user use basic command line. For example user can add event with simply type add "Something to be added.".I wanna highlight addwhen user type this command. Can any one implement a jTextField.

Answer 1

An idea would be to use a StyleDocument and DocumentFilter

This is actually based on this question, but I wasn't sure if I could attempt to use a JTextField

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultHighlighter.DefaultHighlightPainter;
import javax.swing.text.DefaultStyledDocument;
import javax.swing.text.DocumentFilter;
import javax.swing.text.DocumentFilter.FilterBypass;
import javax.swing.text.JTextComponent;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.StyleConstants;

public class TextFieldHighlighter {

    public static void main(String[] args) {
        new TextFieldHighlighter();
    }

    public TextFieldHighlighter() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JTextField field = new JTextField(new DefaultStyledDocument(), null, 20);

                ((AbstractDocument) field.getDocument()).setDocumentFilter(new HighlightDocumentFilter(field));
                JFrame frame = new JFrame("Test");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new GridBagLayout());
                frame.add(field);
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }

        });
    }

    public class HighlightDocumentFilter extends DocumentFilter {

        private DefaultHighlightPainter highlightPainter = new DefaultHighlightPainter(Color.YELLOW);
        private JTextComponent field;
        private SimpleAttributeSet background;

        public HighlightDocumentFilter(JTextComponent field) {
            this.field = field;
            background = new SimpleAttributeSet();
            StyleConstants.setBackground(background, Color.RED);
        }

        @Override
        public void insertString(FilterBypass fb, int offset, String text, AttributeSet attr) throws BadLocationException {
            super.insertString(fb, offset, text, attr);
        }

        @Override
        public void remove(FilterBypass fb, int offset, int length) throws BadLocationException {
            super.remove(fb, offset, length);
        }

        @Override
        public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet attrs) throws BadLocationException {

            String match = "and";

            super.replace(fb, offset, length, text, attrs);

            int startIndex = offset - match.length();
            if (startIndex >= 0) {

                String last = fb.getDocument().getText(startIndex, match.length()).trim();
                if (last.equalsIgnoreCase(match)) {

                    field.getHighlighter().addHighlight(startIndex, startIndex + match.length(), highlightPainter);

                }

            }
        }
    }
}