java 突出显示 JTextArea 中的特定行/行

Highlight one specific row/line in JTextArea

提问by Jeffrey Odametey

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.

我试图仅突出显示 中的一个特定行JTextArea，但我不知道如何去做。我需要获取特定行然后突出显示它。我已经阅读了其他帖子，但我仍然不明白如何将它们组合在一起来解决我的问题......帮助将不胜感激。

回答by nIcE cOw

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

尝试使用此代码示例，并询问是否有不清楚的地方：

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();
            }
        });
    }
}

Here is the output of it :

这是它的输出：

回答by Vishal Chaudhari

If you are unable to select TextArea to TextField reason is button click causes the JTextArea to lose focus and thus not show its selection. on button click event use btnImport.transferFocusBackward();to resolve issue.

如果您无法选择 TextArea 到 TextField，原因是单击按钮会导致 JTextArea 失去焦点，因此不会显示其选择。按钮单击事件用于btnImport.transferFocusBackward();解决问题。

回答by Amina Sid

do like that : this is the text area swing of java

这样做：这是java的文本区域摆动

JTextArea area = new JTextArea(); 
int startIndex = area.getLineStartOffset(2);
int endIndex = area.getLineEndOffset(2);
painter = new DefaultHighlighter.DefaultHighlightPainter(Color.RED);
area.getHighlighter().addHighlight(startIndex, endIndex, painter);