突出显示JTextArea中的一个特定行/行 [英] Highlight one specific row/line in JTextArea

问题描述

我试图突出显示 JTextArea 中的一个特定行，但我不知道要去做什么。我需要获取特定的行然后突出显示它。我已经阅读了其他帖子，但我仍然不明白如何将它们结合在一起来解决我的问题...帮助将非常感激。

I am trying to highlight just one specific row in JTextArea, but I have no idea as to going about it. I need to get the specific row and then highlight it. I've read the other posts, but I still do not understand how to bring it together to solve my problem...help would be much appreciated.

推荐答案

试试这个代码示例，并询问是否有不明确的事情：

Try your hands on this code example, and do ask if something is not clear :

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;

public class TextHighlight
{
    private JTextArea tarea;
    private JComboBox cbox;
    private JTextField lineField;
    private String[] colourNames = {"RED", "ORANGE", "CYAN"};

    private Highlighter.HighlightPainter painter;

    private void createAndDisplayGUI()
    {
        final JFrame frame = new JFrame("Text HIGHLIGHT");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        JPanel contentPane = new JPanel();
        contentPane.setBorder(BorderFactory.createTitledBorder(
                BorderFactory.createEmptyBorder(5, 5, 5, 5), "Highlighter JTextArea"));

        tarea = new JTextArea(10, 10);
        JScrollPane scrollPane = new JScrollPane(tarea);
        contentPane.add(scrollPane);

        JButton button = new JButton("HIGHLIGHT TEXT");
        button.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                int selection = JOptionPane.showConfirmDialog(
                        frame, getOptionPanel(), "Highlighting Options : ", JOptionPane.OK_CANCEL_OPTION
                                                , JOptionPane.PLAIN_MESSAGE);
                if (selection == JOptionPane.OK_OPTION)                             
                {
                    System.out.println("OK Selected");
                    int lineNumber = Integer.parseInt(lineField.getText().trim());
                    try
                    {
                        int startIndex = tarea.getLineStartOffset(lineNumber);
                        int endIndex = tarea.getLineEndOffset(lineNumber);
                        String colour = (String) cbox.getSelectedItem();

                        if (colour == colourNames[0])
                        {
                            System.out.println("RED Colour");
                            painter = new DefaultHighlighter.DefaultHighlightPainter(Color.RED);
                            tarea.getHighlighter().addHighlight(startIndex, endIndex, painter);
                        }
                        else if (colour == colourNames[1])
                        {
                            System.out.println("ORANGE Colour");
                            painter = new DefaultHighlighter.DefaultHighlightPainter(Color.ORANGE);
                            tarea.getHighlighter().addHighlight(startIndex, endIndex, painter);
                        }
                        else if (colour == colourNames[2])
                        {
                            System.out.println("CYAN Colour");
                            painter = new DefaultHighlighter.DefaultHighlightPainter(Color.CYAN);
                            tarea.getHighlighter().addHighlight(startIndex, endIndex, painter);
                        }
                    }
                    catch(BadLocationException ble)
                    {
                        ble.printStackTrace();
                    }
                }
                else if (selection == JOptionPane.CANCEL_OPTION)
                {
                    System.out.println("CANCEL Selected");
                }
                else if (selection == JOptionPane.CLOSED_OPTION)
                {
                    System.out.println("JOptionPane closed deliberately.");
                }
            }
        });

        frame.add(contentPane, BorderLayout.CENTER);
        frame.add(button, BorderLayout.PAGE_END);

        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private JPanel getOptionPanel()
    {
        JPanel panel = new JPanel();
        panel.setLayout(new GridLayout(0, 2, 5, 5));

        JLabel lineNumberLabel = new JLabel("Enter Line Number : ");
        lineField = new JTextField(10);

        JLabel colourLabel = new JLabel("Select One Colour : ");
        cbox = new JComboBox(colourNames);

        panel.add(lineNumberLabel);
        panel.add(lineField);
        panel.add(colourLabel);
        panel.add(cbox);

        return panel;
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new TextHighlight().createAndDisplayGUI();
            }
        });
    }
}

以下是它的输出：

这篇关于突出显示JTextArea中的一个特定行/行的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！