GUI不出现

Question

我有一个Main类，它有一个公共的静态void Main（String[]args）{}。我还有一个叫做appGUI的类。我一直在尝试在运行主类时加载GUI，但什么都没有发生，甚至没有任何错误…：(

这里是主类：

    public class Main {

    /**
     * @param args
     */

    public static void main(String[] args) throws Exception {

        appGUI gui = new appGUI();
    }

}

这里是appGUI类：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/*
 * Created by JFormDesigner on Wed Apr 03 19:24:35 BST 2013
 */



/**
 * @author Hrach Ghapantsyan
 */
public class appGUI extends JFrame {
    public appGUI() {
        initComponents();
    }

    private void loginButtonActionPerformed(ActionEvent e) {
        // TODO add your code here
    }

    private void initComponents() {
        // JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
        // Generated using JFormDesigner Evaluation license - Hrach Ghapantsyan
        loginPasswordField = new JPasswordField();
        loginUsernameField = new JTextField();
        usernameLabel = new JLabel();
        passwordLabel = new JLabel();
        loginButton = new JButton();
        titleLabel = new JLabel();

        //======== this ========
        setTitle("Experimental X | Administrator Login");
        Container contentPane = getContentPane();
        contentPane.setLayout(null);
        contentPane.add(loginPasswordField);
        loginPasswordField.setBounds(80, 65, 100, loginPasswordField.getPreferredSize().height);
        contentPane.add(loginUsernameField);
        loginUsernameField.setBounds(80, 35, 100, loginUsernameField.getPreferredSize().height);

        //---- usernameLabel ----
        usernameLabel.setText("Username:");
        contentPane.add(usernameLabel);
        usernameLabel.setBounds(20, 40, 55, usernameLabel.getPreferredSize().height);

        //---- passwordLabel ----
        passwordLabel.setText("Password:");
        contentPane.add(passwordLabel);
        passwordLabel.setBounds(20, 70, 55, passwordLabel.getPreferredSize().height);

        //---- loginButton ----
        loginButton.setText("Login");
        loginButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                loginButtonActionPerformed(e);
            }
        });
        contentPane.add(loginButton);
        loginButton.setBounds(80, 95, 100, loginButton.getPreferredSize().height);

        //---- titleLabel ----
        titleLabel.setText("Experimental X | Administrator Login");
        contentPane.add(titleLabel);
        titleLabel.setBounds(45, 10, 190, titleLabel.getPreferredSize().height);

        { // compute preferred size
            Dimension preferredSize = new Dimension();
            for(int i = 0; i < contentPane.getComponentCount(); i++) {
                Rectangle bounds = contentPane.getComponent(i).getBounds();
                preferredSize.width = Math.max(bounds.x + bounds.width, preferredSize.width);
                preferredSize.height = Math.max(bounds.y + bounds.height, preferredSize.height);
            }
            Insets insets = contentPane.getInsets();
            preferredSize.width += insets.right;
            preferredSize.height += insets.bottom;
            contentPane.setMinimumSize(preferredSize);
            contentPane.setPreferredSize(preferredSize);
        }
        setSize(270, 170);
        setLocationRelativeTo(getOwner());
        // JFormDesigner - End of component initialization  //GEN-END:initComponents
    }

    // JFormDesigner - Variables declaration - DO NOT MODIFY  //GEN-BEGIN:variables
    // Generated using JFormDesigner Evaluation license - Hrach Ghapantsyan
    private JPasswordField loginPasswordField;
    private JTextField loginUsernameField;
    private JLabel usernameLabel;
    private JLabel passwordLabel;
    private JButton loginButton;
    private JLabel titleLabel;
    // JFormDesigner - End of variables declaration  //GEN-END:variables
}

我尝试过在Eclipse和netbean上运行主类，但是它运行了几秒钟后就停止了。我没有得到任何错误。在座的各位有什么建议吗？谢谢。

Answer 1

public class appGUI extends JFrame {

    setVisible(true);

   // ----
}

放置此代码以使其可见。

Answer 2

确保在GUI上调用setVisible（true）。

Answer 3

您尚未调用JFrame#setVisible：

gui.setVisible(true);

一些注意事项：

• 避免使用null布局。始终使用布局管理器
• 不要使用setXXXSize方法。覆盖getPreferredSize方法以确定组件大小
• 与扩展JFrame不同，您通常希望创建一个JFrame并直接使用它
• 考虑使用初始线程在EDT中创建JFrame