Java Swing : Maximising a JTable display

Question

我目前有一个带有 2 个 Jpanel 的简单 Java GUI，即 panel1 和 panel 2。panel1 用于图像显示和标签显示，它可以正常工作。

面板 2 用于显示 JTable 中的数据。我遇到的问题是在没有垂直滚动 Pane 的情况下显示表格中的所有数据，而不是显示带有滚动 Pane 的表格部分。这在 GUI 中造成了严重的差距，我希望通过一次显示所有表格数据来纠正它。

我已经尝试在包含表格的面板、表格本身以及滚动 Pane 上使用 setPrefferedSize，但现在我完全不知所措!一如既往地欢迎任何建议。

import javax.swing.*;
import java.awt.*;
import javax.imageio.*;
import java.io.*;
import java.awt.image.BufferedImage;
import java.util.*;
import javax.swing.table.DefaultTableCellRenderer;

public class GUI2 extends JFrame {

    public int PADDING = 10;
    public GUI2() {

        initUI();
    }

    public final void initUI() {

        // Menu Bar and Menu Items setup
        JMenuBar menuBar;
        JMenu menu;
        JMenuItem menuItem;

        menuBar = new JMenuBar();
        menu = new JMenu("Menu");
        menuBar.add(menu);

        JMenuItem menuNew = new JMenuItem("New");
        menu.add(menuNew);
        JMenuItem menuOpen = new JMenuItem("Open");
        menu.add(menuOpen);
        JMenuItem menuSave = new JMenuItem("Save");
        menu.add(menuSave);
        JMenuItem menuExit = new JMenuItem("Exit");
        menu.add(menuExit);

        setLayout(new GridLayout(4,1));
        setJMenuBar(menuBar);


        JPanel jp1 = new JPanel(new BorderLayout());
        jp1.setBorder(BorderFactory.createEmptyBorder(PADDING, PADDING, PADDING, PADDING));
        jp1.setBorder(BorderFactory.createLineBorder(Color.black));
        jp1.setPreferredSize(new Dimension(800, 300));

        // Create subpanels
        JPanel sp1 = new JPanel();
        JPanel sp2 = new JPanel(new GridLayout(8, 2));
        sp1.setBorder(BorderFactory.createLineBorder(Color.black));

        // Set up sub panel 1
        BufferedImage myPicture = null;
        try{
            myPicture = ImageIO.read(new File("bat.jpg"));
        }catch(IOException e){
            System.out.println("Image not Loaded!");
            e.printStackTrace();
        }

        JLabel picLabel             = new JLabel(new ImageIcon( myPicture ));
        jp1.add(picLabel);


        // For sub panel 2
        JLabel label_location       = new JLabel("Location: ");
        JLabel label_datetime       = new JLabel("Date & Time: ");
        JLabel label_measurementNum = new JLabel("Measurement Number: ");
        JLabel label_vehicleType    = new JLabel("Vehicle Type: ");
        JLabel label_temperature    = new JLabel("Temperature: ");
        JLabel label_weather        = new JLabel("Weather Conditions: ");
        JLabel label_testPersons    = new JLabel("Test Persons: ");
        JLabel label_testType       = new JLabel("Test Type: ");

        String timestamp            = " ";
        Date date                   = new Date();
        timestamp                   = date.toString();


        JTextField  location        = new JTextField();
        JLabel      datetime        = new JLabel(timestamp);
        JLabel      measurementNum  = new JLabel("AZUWADA87623Q");          
        JLabel      vehicleType     = new JLabel("Batmobile");                   
        JTextField  temperature     = new JTextField(); 
        JTextField  weather         = new JTextField();
        JTextField  testPersons     = new JTextField();
        JTextField  testType        = new JTextField();



        sp1.add(picLabel);
        sp2.add(label_location);
        sp2.add(location);
        sp2.add(label_datetime);
        sp2.add(datetime);
        sp2.add(label_measurementNum);
        sp2.add(measurementNum);
        sp2.add(label_vehicleType);
        sp2.add(vehicleType);
        sp2.add(label_temperature);
        sp2.add(temperature);
        sp2.add(label_weather);
        sp2.add(weather);
        sp2.add(label_testPersons);
        sp2.add(testPersons);
        sp2.add(label_testType);
        sp2.add(testType);



        label_location.setHorizontalAlignment(SwingConstants.LEFT);                         



        jp1.add(sp1, BorderLayout.WEST);
        jp1.add(sp2, BorderLayout.EAST);

        add(jp1);



        JPanel jp2 = new JPanel();
        jp2.setPreferredSize(new Dimension(900, 900));


        String[] columnNames = {"", "DAW Referernce Scale", " WIM Vehicle 1"}; 
        Object[][] data = { {"Vehicle Summary", new Integer(100), new Integer(200)},  // Header 1: Green
                            {"Axle Numbers", new Integer(100), new Integer(200)},
                            {"Axle Code", new Integer(100), new Integer(200)},
                            {"Axle Distances (cm)", new Integer(100), new Integer(200)},
                            {"Vehicle Speed (km/h)", new Integer(100), new Integer(200)},
                            {"Gross Weight", new Integer(100), new Integer(200)}, 
                            {"Axle Weight 1", new Integer(100), new Integer(200)},
                            {"Axle Weight 2", new Integer(100), new Integer(200)},

                            // Measurements for Axle 1
                            // Weights
                            {"Axle 1", new Integer(100), new Integer(200)},   // Header 1: Green
                            {"Weights (kg)", " ", " "},
                            {"Axle Weights AW1", new Integer(100), new Integer(200)},
                            {"Wheel Weights WW1R", new Integer(100), new Integer(200)},
                            {"Wheel Weights WW1L", new Integer(100), new Integer(200)},
                            // Dimensions
                            {"Dimensions (cm or cm2)", new Integer(100), new Integer(200)},
                            {"Axle Width AW1", new Integer(100), new Integer(200), new Integer(200)}, 
                            {"Tire Footprints 1R Length", new Integer(100), new Integer(200)},
                            {"Tire Footprints 1R Width", new Integer(100), new Integer(200)},
                            {"Tire Footprints 1R FootPrint", new Integer(100), new Integer(200)},
                            {"Tire Footprints 1L Length", new Integer(100), new Integer(200)},
                            {"Tire Footprints 1L Width", new Integer(100), new Integer(200)},
                            {"Tire Footprints 1L FootPrint", new Integer(100), new Integer(200)},
                            // Speed
                            {"Speed", " ", " "},
                            {"Vehicle Speed", new Integer(100), new Integer(200)},
                            {"Axle Speed", new Integer(100), new Integer(200)},
                            {"Tyre Speed 1R", new Integer(100), new Integer(200)},
                            {"Tyre Speed 1L", new Integer(100), new Integer(200)},

                            // Measurements for Axle 2
                            // Weights
                            {"Axle 2", " ", " "},   // Header 1: Green
                            {"Weights (kg)", " ", " "},
                            {"Axle Weights AW2", new Integer(100), new Integer(200)},
                            {"Wheel Weights WW2R", new Integer(100), new Integer(200)},
                            {"Wheel Weights WW2L", new Integer(100), new Integer(200)},
                            // Dimensions
                            {"Dimensions (cm or cm2)", " ", " "},
                            {"Axle Width AW2", new Integer(100), new Integer(200)}, 
                            {"Tire Footprints 2R Length", new Integer(100), new Integer(200)},
                            {"Tire Footprints 2R Width", new Integer(100), new Integer(200)},
                            {"Tire Footprints 2R FootPrint", new Integer(100), new Integer(200)},
                            {"Tire Footprints 2L Length", new Integer(100), new Integer(200)},
                            {"Tire Footprints 2L Width", new Integer(100), new Integer(200)},
                            {"Tire Footprints 2L FootPrint", new Integer(100), new Integer(200)},
                            // Speed
                            {"Speed", " ", " "},
                            {"Vehicle Speed", new Integer(100), new Integer(200)},
                            {"Axle Speed", new Integer(100), new Integer(200)},
                            {"Tyre Speed 2R", new Integer(100), new Integer(200)},
                            {"Tyre Speed 2L", new Integer(100), new Integer(200)},};


        final JTable table = new JTable(data, columnNames); 

        table.getColumnModel().getColumn(0).setCellRenderer(new CustomRenderer());
        table.setPreferredScrollableViewportSize(new Dimension(500, 70)); 
        table.setFillsViewportHeight(true); 

        JScrollPane scrollPane = new JScrollPane(table); 

        jp2.add(scrollPane);
        add(scrollPane);


        setSize(400,300);
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);

    }

            //Custom Renderer - does the default rendering except if told the row should be a different color
    public static class CustomRenderer extends DefaultTableCellRenderer{

        public CustomRenderer(){
            super();
            //Customize the rendering however you want
            setBackground(UIManager.getColor("TableHeader.background"));
        }
    }


    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {

            public void run() {

                try {
                    UIManager.setLookAndFeel("javax.swing.plaf.nimbus.NimbusLookAndFeel");
                } catch (Exception e) {
                    e.printStackTrace();
                }

                GUI2 ex = new GUI2();
                ex.setVisible(true);
            }
        });
    }
}

Answer 1

如果我理解正确，您希望 JTable 垂直拉伸(stretch)以占用顶部面板下方的所有可用空间。如果是这样，您需要更改布局管理器。现在您使用 4 行的 Gridlayout。 GridLayout 将您的框架分成 4 个等高的垂直 block 。第一个 block 包含顶部面板 - jp1，第二个 block 包含带有 JTable 的 JScrollPane，两个底部 block 是空的，但占框架高度的一半。

您可以尝试使用BoxLayout、BorderLayout 或GridBagLayout。