java - 使用 Java Swing 将 JTable 中的内容输出到 TextArea

Question

所以我正在尝试使用 Java Swing 制作一个基本的 GUI。我有一些按钮，一个带有输入按钮的文本字段以及一个更大的文本区域。单击“显示所有团队”按钮时，此按钮的操作侦听器应将 JTable 内容输出到文本区域，但它不起作用并且没有任何输出。

package footballmanager;

import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JList;
import javax.swing.JTextPane;
import javax.swing.JLabel;
import javax.swing.JTextArea;
import javax.swing.JScrollBar;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.table.DefaultTableModel;

public class FootballGUI 
    {
        private JFrame frame;
        private JTextField textField;


    //Launch the application.
    public static void main(String[] args)
    {
        FootballGUI window = new FootballGUI();
        window.frame.setVisible(true);
    }
    
    //Display the application
       public void displayGUI() {
       this.frame.setVisible(true);
   }
    
    //Create the application.
            
    public FootballGUI() 
    {
        frame = new JFrame();
        frame.setBounds(100, 100, 611, 471);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        // Text area
        final JTextArea testArea = new JTextArea(5,20);
        testArea.setBounds(6, 6, 329, 343);
        frame.getContentPane().add(testArea);
        
        // Buttons on the window
        JButton displayTeams = new JButton("Display all teams");
        // (x, y, w, h)
        displayTeams.setBounds(370, 6, 200, 29);
        frame.getContentPane().add(displayTeams);
        
        
        class MyActionListener implements ActionListener{
        public void actionPerformed(ActionEvent e) {
//                    String s = String.format("%s %s", "Club name", "Club points");
//                    testArea.setText(s);
                        String[] columnNames = {"First Name",
                                                "Last Name",
                                                "Sport",
                                                "# of Years",
                                                "Vegetarian"};
                                            Object[][] data = {
                        {"Kathy", "Smith",
                         "Snowboarding", new Integer(5), new Boolean(false)},
                        {"John", "Doe",
                         "Rowing", new Integer(3), new Boolean(true)},
                        {"Sue", "Black",
                         "Knitting", new Integer(2), new Boolean(false)},
                        {"Jane", "White",
                         "Speed reading", new Integer(20), new Boolean(true)},
                        {"Joe", "Brown",
                         "Pool", new Integer(10), new Boolean(false)}
                    };
                         JTable table = new JTable(data, columnNames);
                         
                         DefaultTableModel model1 = (DefaultTableModel) table.getModel();
                         int nRow = model1.getRowCount(), nCol = model1.getColumnCount();
                         Object [][] tableData = new Object [nRow] [nCol];
                         for (int i = 0; i < nRow; i++){
                             for (int j = 0; j < nCol; j++){
                             tableData [i][j] = model1.getValueAt (i,j);
                             testArea.append((String) tableData [i][j] + "\t");
                             }
                         }
                         testArea.append("\n");
                 
                 
                }
        }
            
        displayTeams.addActionListener(new MyActionListener());
        
        JButton goalSort = new JButton("Sort list by goals");
        goalSort.setBounds(370, 40, 200, 29);
        frame.getContentPane().add(goalSort);

        JButton winSort = new JButton("Sort list by most wins");
        winSort.setBounds(370, 74, 200, 29);
        frame.getContentPane().add(winSort);

        JButton randomMatch = new JButton("Generate random match");
        randomMatch.setBounds(370, 280, 200, 29);
        frame.getContentPane().add(randomMatch);
        
        JButton displayMatches = new JButton("Display all played matches");
        displayMatches.setBounds(370, 314, 200, 29);
        frame.getContentPane().add(displayMatches);

        JButton btnEnter = new JButton("Search for a match");
        btnEnter.setBounds(518, 404, 85, 39);
        frame.getContentPane().add(btnEnter);

        JScrollBar scrollBar = new JScrollBar();
        scrollBar.setBounds(320, 6, 15, 338);
        frame.getContentPane().add(scrollBar);
        
        textField = new JTextField();
        textField.setBounds(5, 410, 508, 28);
        frame.getContentPane().add(textField);
        textField.setColumns(10);
        
        JLabel lblMapGoesHere = new JLabel("List goes here");
        lblMapGoesHere.setBounds(342, 37, 263, 312);
        frame.getContentPane().add(lblMapGoesHere);
    }
}

标签： javaswing

Answer 1

我重新编写了您的 GUI 以使用JTable.

这是修改后的 GUI 的样子。

这是左键单击“显示所有团队”按钮后的样子。

这是我对您的 GUI 所做的主要更改。

1. 我通过调用该SwingUtilities invokeLater方法启动了 Java 应用程序。此方法确保在Event Dispatch Thread上创建和使用 Swing 组件。

2. 我为我创建的两个使用了Swing 布局管理器。JPanelsJFrame 内容窗格使用默认的BorderLayout. 使用JTable JPanel默认值FlowLayout。使用JButton JPanel一个GridBagLayout. 您使用的固定布局不允许我调整JTextArea您正在使用的大小。

3. 我用 aJTable来显示团队。我把JTableinJScrollPane和JScrollPane里面的 JPanel。

4. 我在创建 GUI 之前创建了列和数据。通常，您要先创建应用程序模型，然后再创建 GUI。这是模型/视图/控制器模式的一个简单示例。

这是我使用的完整的可运行代码。

import java.awt.BorderLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableModel;

public class FootballGUI implements Runnable {

    private DefaultTableModel model;
    private JFrame frame;
    private JTable table;
    private String[][] data;

    // Launch the application.
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new FootballGUI());
    }

    public FootballGUI() {
        String[] columnNames = { "First Name", "Last Name", "Sport", 
                "# of Years", "Vegetarian" };
        this.model = new DefaultTableModel();

        for (String s : columnNames) {
            model.addColumn(s);
        }

        this.data = new String[][] { { "Kathy", "Smith", "Snowboarding", "5", "false" },
                { "John", "Doe", "Rowing", "3", "true" }, 
                { "Sue", "Black", "Knitting", "2", "false" },
                { "Jane", "White", "Speed reading", "20", "true" }, 
                { "Joe", "Brown", "Pool", "10", "false" } };
    }

    // Create the application.
    @Override
    public void run() {
        frame = new JFrame("Football GUI");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.add(createTablePanel(), BorderLayout.CENTER);
        frame.add(createButtonPanel(), BorderLayout.AFTER_LINE_ENDS);

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

    private JPanel createTablePanel() {
        JPanel panel = new JPanel();

        table = new JTable(model);
        JScrollPane scrollPane = new JScrollPane(table);
        panel.add(scrollPane);

        return panel;
    }

    private JPanel createButtonPanel() {
        JPanel panel = new JPanel(new GridBagLayout());
        panel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));

        GridBagConstraints gbc = new GridBagConstraints();
        gbc.anchor = GridBagConstraints.CENTER;
        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.gridx = 0;
        gbc.gridy = 0;
        gbc.insets = new Insets(5, 5, 5, 5);
        gbc.weightx = 1.0d;

        JButton displayTeams = new JButton("Display all teams");
        displayTeams.addActionListener(new MyActionListener());
        panel.add(displayTeams, gbc);

        gbc.gridy++;
        JButton goalSort = new JButton("Sort list by goals");
        panel.add(goalSort, gbc);

        gbc.gridy++;
        JButton winSort = new JButton("Sort list by most wins");
        panel.add(winSort, gbc);

        gbc.gridy++;
        JButton randomMatch = new JButton("Generate random match");
        panel.add(randomMatch, gbc);

        gbc.gridy++;
        JButton displayMatches = new JButton("Display all played matches");
        panel.add(displayMatches, gbc);

        gbc.gridy++;
        JButton btnEnter = new JButton("Search for a match");
        panel.add(btnEnter, gbc);

        return panel;
    }

    public class MyActionListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent event) {
            int count = model.getRowCount();
            for (int i = 0; i < count; i++) {
                model.removeRow(0);
            }
            
            for (int i = 0; i < data.length; i++) {
                model.addRow(data[i]);
            }
        }

    }
    
}