Question

我是Java GUI的初学者。我试图在Netbeans中创建一个简单的登录表单。它由名为TestSuiteFrame的JFrame和一个名为TestSuiteEntryPanel的JPanel组成，其中包含几个标签，文本框和一个按钮。我还没有添加“业务逻辑”。

问题在于，当我运行项目时，没有任何反应。几秒钟后，我得到这个作为输出：跑： Java结果：-1073740771 建立成功（总时间：15秒）

就是这样。没有窗口出现。我究竟做错了什么？

以下是代码：

        package TPackage;

public class TestSuiteFrame extends javax.swing.JFrame {

    /**
     * Creates new form TestSuiteFrame
     */
    public TestSuiteFrame() {
        initComponents();
        TestSuiteEntryPanel a = new TestSuiteEntryPanel();
        add(a);


    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 400, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 300, Short.MAX_VALUE)
        );

        pack();
    }// </editor-fold>                        

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(TestSuiteFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(TestSuiteFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(TestSuiteFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(TestSuiteFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>
        //System.out.println("abc");
        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                TestSuiteFrame b = new TestSuiteFrame();
                b.setTitle("Login");
                b.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                //b.pack();
                b.setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    // End of variables declaration                   
}

小组代码：

package TPackage;
public class TestSuiteEntryPanel extends javax.swing.JPanel {

/**
 * Creates new form TestSuiteEntryPanel
 */
public TestSuiteEntryPanel() {
    initComponents();
}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    labelEntryName = new javax.swing.JLabel();
    labelEntryPassword = new javax.swing.JLabel();
    ButtonEntryLogin = new javax.swing.JButton();
    TextEntryName = new javax.swing.JTextField();
    TextEntryPassword = new javax.swing.JPasswordField();

    setPreferredSize(new java.awt.Dimension(350, 325));

    labelEntryName.setText("Name:");

    labelEntryPassword.setText("Password:");

    ButtonEntryLogin.setText("Login");

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
    this.setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
            .addGap(37, 37, 37)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                .addComponent(labelEntryPassword)
                .addComponent(labelEntryName))
            .addGap(18, 18, 18)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                .addComponent(TextEntryName, javax.swing.GroupLayout.DEFAULT_SIZE, 221, Short.MAX_VALUE)
                .addComponent(TextEntryPassword))
            .addContainerGap(24, Short.MAX_VALUE))
        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
            .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addComponent(ButtonEntryLogin)
            .addGap(45, 45, 45))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(44, 44, 44)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(labelEntryName)
                .addComponent(TextEntryName, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(18, 18, 18)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(labelEntryPassword)
                .addComponent(TextEntryPassword, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(18, 18, 18)
            .addComponent(ButtonEntryLogin)
            .addContainerGap(182, Short.MAX_VALUE))
    );
}// </editor-fold>                        


// Variables declaration - do not modify                     
private javax.swing.JButton ButtonEntryLogin;
private javax.swing.JTextField TextEntryName;
private javax.swing.JPasswordField TextEntryPassword;
private javax.swing.JLabel labelEntryName;
private javax.swing.JLabel labelEntryPassword;
// End of variables declaration                   
}

Answer 1

从initComponents课程中删除整个TestSuiteFrame方法（您甚至不需要它），并在pack方法中取消注释main。这是GroupLayout的问题。您的代码应如下所示：

import javax.swing.*;

public class TestSuiteFrame extends javax.swing.JFrame {

    public TestSuiteFrame() {
        TestSuiteEntryPanel a = new TestSuiteEntryPanel();
        add(a);

    }


    public static void main(String args[]) {
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(TestSuiteFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(TestSuiteFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(TestSuiteFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(TestSuiteFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }

        java.awt.EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                TestSuiteFrame b = new TestSuiteFrame();
                b.setTitle("Login");
                b.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                b.pack();
                b.setVisible(true);
            }
        });
    }

}

另请注意，在pack上添加组件后会出现JFrame。学习如何手动编写Java Swing代码，避免使用那个可怕的Matisse GUI构建器。

Answer 2

你需要调用pack（）;将所有组件添加到框架后。所以推荐pack（）;调用setVilisble（true）;并删除构造函数中的那个： - ）我希望有所帮助。

Answer 3

确保导入必要的包（即使您已经导入了）

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

运行你的程序。如果没有显示任何内容，并且您使用的是Windows，请按alt - tab以循环显示已打开的应用程序。

或者，执行程序后。按ctrl + alt + del，然后在Windows任务管理器的Applications标签下查看是否存在名为Login的任务（您的java app）。

我尝试了您的代码，会显示一个窗口。您的程序中的JFrame可能会被其他应用程序隐藏。

如果您使用像Netbeans这样的IDE，请确保main program file指向main()内的TestSuiteFrame。

如果仍然没有显示，请尝试运行单个文件而不是整个项目。 shift + F5或右键单击TestSuiteFrame.java =＆gt; Netbeans run file。

除了所有内容之外，请确保您运行的是正确的文件。您只需在System.out.println()内编写一些main()语句即可。只需检查控制台是否在运行程序时打印这些行。有很多方法可以检查。

如果控制台没有打印那些println语句，那么BINGO！您可能没有运行正确的java文件/项目。

Java GUI Windows根本不显示

3 个答案: