java - JTable 不会显示在 JPanel 上

Question

您好，我已经创建了一个 Jtable，可以让它显示在我的框架上，但不能显示在我的 JFrame 之上的 JPanel 上。我似乎无法改变

import java.awt.;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.io.;import java.util.ArrayList;import java.util.Comparator;import javax.swing.;import javax.swing.table.;
public class Main{    DefaultTableModel table_model;    String[][] addressData = new String[10][5];    JPanel panel;    JFrame frame;    JButton loadData;    int count,index,row =0;    String thisLine;    ArrayList People = new ArrayList();
public Main()
{
    //Creating JFrame and setting properties
    frame = new JFrame();
    frame.setResizable(false);
    frame.setTitle("Address Book");
    frame.setSize(800,600);
    frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);

    //Creating JPanel and setting properties
    panel = new JPanel();
    panel.setLayout(null);
    panel.setBackground(new Color(77,81,84));

    //Setting the table and Scroll Bars
    this.table_model = new DefaultTableModel(addressData, new String[]{"First Name", "Surname", "Home Number", "Mobile Number", "Address", "Postcode"});
    JTable table = new JTable(this.table_model);
    table.setBounds(130, 40, 200, 200);
    panel.add(new JScrollPane(table, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS));

    //Load Data button, reading file in and adding data to ArrayList then Array of Arrays
    loadData = new JButton("Load File");
    loadData.setBounds(10, 10, 100, 20);
    loadData.addActionListener(new ActionListener()
    {
        public void actionPerformed(ActionEvent e)
        {
            try
            {
                BufferedReader reader = new BufferedReader(new FileReader("file/address.buab"));
                while ((thisLine = reader.readLine()) !=null)
                {
                    if (row >= 4)
                    {
                        index++;
                        row = 0;
                        People.add(thisLine);
                        addressData[index][row] = People.get(count);
                        count++;
                        row++;
                    }
                    else
                    {
                    People.add(thisLine);
                    addressData[index][row] = People.get(count);
                    count++;
                    row++;
                    }
                }
                reader.close();
            }
            catch (IOException ex)
            {
                System.err.println("Input Exception, Check address.buab File");
            }
        }
    });
    panel.add(loadData);

    //Auto sort on table fields
    TableRowSorter<TableModel> sorter = new TableRowSorter<TableModel>(this.table_model);
    sorter.setComparator(1, new Comparator<Integer>()
    {
        public int compare(Integer o1, Integer o2)
        {
            return o1.compareTo(o2);
        }

        public boolean equals(Object obj)
        {
            return obj.equals(this);
        }
    });

    table.setRowSorter(sorter);

    frame.getContentPane().add(panel);
    frame.setVisible(true);
}

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

}

关于如何将表格设置为在我的 JPanel 上可见的任何想法

Answer 1

您需要使用特定的布局管理器创建您的 JPanel，然后添加具有适当约束的组件(JTable 和 JButton)以导致它们出现在面板的正确区域。目前您正在将面板的布局管理器设置为 null，这几乎肯定是不正确的。您可能想查看 Using Layout Managers教程。

要考虑的一个简单布局管理器是 BorderLayout。例如:

// Create JPanel with BorderLayout layout manager.
JPanel panel = new JPanel(new BorderLayout());

// Add JTable to panel center.  This component will expand
// to take up available space.
panel.add(myTableScrollPane, BorderLayout.CENTER);

// Add button to the bottom of the panel.
panel.add(myButton, BorderLayout.SOUTH);