Question

我已将初始化方法设为公开，没有帮助，并且我已将此处和外部类别设置为可见，如下所示，任何帮助都将受到赞赏。我使用eclipse中的窗口构建工具

创建了gui

GeneralWindow frame = new GeneralWindow();
                        frame.setVisible(true);

包gui;

import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UIManager.LookAndFeelInfo;
import javax.swing.JLabel;
import javax.swing.JTextArea;
import java.awt.Font;

public class GeneralWindow extends JFrame{

    private JFrame frame;
    private JTextField textField;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {

        try {
            for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (Exception e) {
            // If Nimbus is not available, you can set the GUI to another look and feel.
        }

        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    GeneralWindow window = new GeneralWindow();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the application.
     */
    public GeneralWindow() {
        initialize();
    }

    /**
     * Initialize the contents of the frame.
     */
    private void initialize() {
        frame = new JFrame();
        frame.setBounds(100, 100, 450, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);

        JButton btnNewButton = new JButton("Order");
        btnNewButton.setBounds(309, 12, 115, 23);
        frame.getContentPane().add(btnNewButton);

        JButton btnNewButton_1 = new JButton("Search");
        btnNewButton_1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
            }
        });
        btnNewButton_1.setBounds(309, 46, 115, 23);
        frame.getContentPane().add(btnNewButton_1);

        JButton btnNewButton_2 = new JButton("Stock");
        btnNewButton_2.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
            }
        });
        btnNewButton_2.setBounds(309, 80, 115, 23);
        frame.getContentPane().add(btnNewButton_2);

        JButton btnNewButton_3 = new JButton("Emplyoees");
        btnNewButton_3.setBounds(309, 114, 115, 23);
        frame.getContentPane().add(btnNewButton_3);

        JButton btnNewButton_4 = new JButton("Price Amend");
        btnNewButton_4.setBounds(309, 148, 115, 23);
        frame.getContentPane().add(btnNewButton_4);

        JButton btnNewButton_5 = new JButton("Total");
        btnNewButton_5.setBounds(309, 182, 115, 23);
        frame.getContentPane().add(btnNewButton_5);

        textField = new JTextField();
        textField.setBounds(10, 228, 178, 20);
        frame.getContentPane().add(textField);
        textField.setColumns(10);

        JLabel lblProductcodeBar = new JLabel("Productcode Bar");
        lblProductcodeBar.setFont(new Font("Tahoma", Font.BOLD, 11));
        lblProductcodeBar.setBounds(10, 209, 125, 14);
        frame.getContentPane().add(lblProductcodeBar);

        JButton btnEnter = new JButton("Enter");
        btnEnter.setBounds(198, 227, 89, 23);
        frame.getContentPane().add(btnEnter);

        JTextArea textArea = new JTextArea();
        textArea.setBounds(10, 11, 277, 196);
        frame.getContentPane().add(textArea);
    }


}

Answer 1

您可以看到GeneralWindow类型的框架frame可见。但是你永远不会在该框架中添加任何组件。相反，您的initialize方法会创建另一个框架，并向该框架添加许多组件。不要创建另一个框架，而是将组件添加到this。

Answer 2

在您的initialize（）中，只需将框架更改为此关键字即可 e.g

 //Remove this line
 frame = new JFrame();
 //change frame to this keyword
 this.setBounds(100, 100, 450, 300);
 this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 this.getContentPane().setLayout(null);

它完成了......

Answer 3

虽然这里提供的两个答案提供了正确的解决方案，但它们都强化了您应该扩展JFrame的观点。一般来说这不是一个好建议，因为你应该赞成合成而不是继承。事实上，你编写代码以将JFrame作为私有成员包含的方式是正确的本能。

我已经包含了一个不会扩展的代码的精简版本JFrame而是在调用JFrame方法时创建createAndDisplayFrame()的实例

public class GeneralWindow {

    private JFrame frame;
    private JButton orderButton;

    public static void main(final String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                GeneralWindow window = new GeneralWindow();
                window.crateAndDisplayFrame();
            }
        });
    }

    public void crateAndDisplayFrame() {
        initialize();
        frame.setVisible(true);
    }

    private void initialize() {
        frame = new JFrame();
        frame.setBounds(100, 100, 450, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);

        orderButton = new JButton("Order");
        orderButton.setBounds(309, 12, 115, 23);
        frame.getContentPane().add(orderButton);
    }

}

当在另一个类中创建我的Gui的Object时，框架会加载，但内部没有任何内容

3 个答案: