Java - Gui 组件不显示

Question

我有这段代码可以创建一个简单的图形用户界面(手动)，我正在尝试在框架上显示图形用户界面组件。但是，当我运行程序时，只显示框架而没有显示组件，例如 JTable。

知道为什么吗？

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

public class GUI extends JFrame {
    public void buildGui() {
        JFrame frame = new JFrame("Hotel TV Scheduler");    
        frame.setVisible(true);

        Container contentPane = frame.getContentPane();

        JPanel mainPanel = new JPanel();
        mainPanel.setLayout(new BorderLayout());

        JPanel listPanel = new JPanel();
        listPanel.setLayout(new FlowLayout());

        JTable chOneTable = new JTable();
        JTable chTwoTable = new JTable();
        JTable listTable = new JTable();

        listPanel.add(chOneTable);
        listPanel.add(chTwoTable);
        listPanel.add(listTable);

        contentPane.add(listPanel);
    }
}

Answer 1

您应该在 JTables 上设置一个 preferredSize()，然后再执行一个 pack()。

编辑:

在 pack() 之后移动了 setVisible(true)。这是order which is used by Sun/Oracle .

public class GUI extends JFrame {
    public void buildGui() {
        JFrame frame = new JFrame("Hotel TV Scheduler");

        Container contentPane = frame.getContentPane();

        JPanel mainPanel = new JPanel();
        mainPanel.setLayout(new BorderLayout());

        JPanel listPanel = new JPanel();
        listPanel.setLayout(new FlowLayout());

        Dimension d = new Dimension(100, 100);

        JTable chOneTable = new JTable();
        chOneTable.setPreferredSize(d);

        JTable chTwoTable = new JTable();
        chTwoTable.setPreferredSize(d);

        JTable listTable = new JTable();
        listTable.setPreferredSize(d);

        listPanel.add(chOneTable);
        listPanel.add(chTwoTable);
        listPanel.add(listTable);

        contentPane.add(listPanel);

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