java - 使用 GridBagLayout 将 JPanel 内的组件居中

Question

我试图将一些组件集中在 JPanel 中，当我在 JPanel 的 GridBagLayout 的“自定义布局”选项中按“测试布局”时，一切正常，但当我运行程序时，它看起来有所不同。

它应该看起来像这样:

相反，当我运行该程序时，它看起来像这样:

该程序的结构如下:

所以有两个问题:

1. 密码字段比电子邮件地址字段大。我尝试将它们的最小、最大和首选大小设置为 (14, 22)，但它不起作用。

2. 为什么按钮是分开的以及如何使它们连接？ (右侧按钮左Inset为0)

这是 initComponents() 函数:

private void initComponents()
    {
        java.awt.GridBagConstraints gridBagConstraints;

        jPanel1 = new javax.swing.JPanel();
        loginButton = new javax.swing.JButton();
        signUpLabel = new javax.swing.JLabel();
        emailTextField = new javax.swing.JTextField();
        passwordField = new javax.swing.JPasswordField();
        star1 = new javax.swing.JLabel();
        star2 = new javax.swing.JLabel();
        loginToggleButton = new javax.swing.JToggleButton();
        signUpToggleButton = new javax.swing.JToggleButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jPanel1.setBackground(new java.awt.Color(42, 46, 55));
        jPanel1.setLayout(new java.awt.GridBagLayout());

        loginButton.setFont(new java.awt.Font("Dialog", 1, 14)); // NOI18N
        loginButton.setText("Login");
        loginButton.addActionListener(new java.awt.event.ActionListener()
        {
            public void actionPerformed(java.awt.event.ActionEvent evt)
            {
                loginButtonActionPerformed(evt);
            }
        });
        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 0;
        gridBagConstraints.gridy = 5;
        gridBagConstraints.gridwidth = 2;
        gridBagConstraints.ipadx = 42;
        gridBagConstraints.ipady = 14;
        gridBagConstraints.anchor = java.awt.GridBagConstraints.NORTHWEST;
        gridBagConstraints.insets = new java.awt.Insets(79, 116, 0, 0);
        jPanel1.add(loginButton, gridBagConstraints);

        signUpLabel.setFont(new java.awt.Font("Dialog", 1, 13)); // NOI18N
        signUpLabel.setText("Don't have an account?");
        signUpLabel.setPreferredSize(new java.awt.Dimension(149, 12));
        signUpLabel.addMouseListener(new java.awt.event.MouseAdapter()
        {
            public void mouseClicked(java.awt.event.MouseEvent evt)
            {
                signUpLabelMouseClicked(evt);
            }
            public void mouseEntered(java.awt.event.MouseEvent evt)
            {
                signUpLabelMouseEntered(evt);
            }
            public void mouseExited(java.awt.event.MouseEvent evt)
            {
                signUpLabelMouseExited(evt);
            }
        });
        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 0;
        gridBagConstraints.gridy = 6;
        gridBagConstraints.gridwidth = 3;
        gridBagConstraints.anchor = java.awt.GridBagConstraints.NORTHWEST;
        gridBagConstraints.insets = new java.awt.Insets(18, 100, 42, 0);
        jPanel1.add(signUpLabel, gridBagConstraints);

        emailTextField.setMaximumSize(new java.awt.Dimension(14, 22));
        emailTextField.setMinimumSize(new java.awt.Dimension(14, 22));
        emailTextField.setPreferredSize(new java.awt.Dimension(14, 22));
        emailTextField.addFocusListener(new java.awt.event.FocusAdapter()
        {
            public void focusGained(java.awt.event.FocusEvent evt)
            {
                emailTextFieldFocusGained(evt);
            }
            public void focusLost(java.awt.event.FocusEvent evt)
            {
                emailTextFieldFocusLost(evt);
            }
        });
        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 0;
        gridBagConstraints.gridy = 1;
        gridBagConstraints.gridwidth = 6;
        gridBagConstraints.gridheight = 2;
        gridBagConstraints.ipadx = 199;
        gridBagConstraints.ipady = 10;
        gridBagConstraints.anchor = java.awt.GridBagConstraints.NORTHWEST;
        gridBagConstraints.insets = new java.awt.Insets(97, 70, 0, 0);
        jPanel1.add(emailTextField, gridBagConstraints);

        passwordField.setMaximumSize(new java.awt.Dimension(14, 22));
        passwordField.addFocusListener(new java.awt.event.FocusAdapter()
        {
            public void focusGained(java.awt.event.FocusEvent evt)
            {
                passwordFieldFocusGained(evt);
            }
            public void focusLost(java.awt.event.FocusEvent evt)
            {
                passwordFieldFocusLost(evt);
            }
        });
        passwordField.addActionListener(new java.awt.event.ActionListener()
        {
            public void actionPerformed(java.awt.event.ActionEvent evt)
            {
                passwordFieldActionPerformed(evt);
            }
        });
        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 0;
        gridBagConstraints.gridy = 3;
        gridBagConstraints.gridwidth = 6;
        gridBagConstraints.gridheight = 2;
        gridBagConstraints.ipadx = 199;
        gridBagConstraints.ipady = 10;
        gridBagConstraints.anchor = java.awt.GridBagConstraints.NORTHWEST;
        gridBagConstraints.insets = new java.awt.Insets(18, 70, 0, 0);
        jPanel1.add(passwordField, gridBagConstraints);

        star1.setForeground(new java.awt.Color(255, 0, 0));
        star1.setText("*");
        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 6;
        gridBagConstraints.gridy = 1;
        gridBagConstraints.anchor = java.awt.GridBagConstraints.NORTHWEST;
        gridBagConstraints.insets = new java.awt.Insets(106, 10, 0, 49);
        jPanel1.add(star1, gridBagConstraints);

        star2.setForeground(new java.awt.Color(255, 0, 0));
        star2.setText("*");
        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 6;
        gridBagConstraints.gridy = 3;
        gridBagConstraints.anchor = java.awt.GridBagConstraints.NORTHWEST;
        gridBagConstraints.insets = new java.awt.Insets(25, 10, 0, 49);
        jPanel1.add(star2, gridBagConstraints);

        loginToggleButton.setBackground(new java.awt.Color(0, 224, 208));
        loginToggleButton.setText("Log In");
        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 1;
        gridBagConstraints.gridy = 0;
        gridBagConstraints.gridwidth = 4;
        gridBagConstraints.ipadx = 34;
        gridBagConstraints.ipady = 8;
        gridBagConstraints.anchor = java.awt.GridBagConstraints.NORTHWEST;
        gridBagConstraints.insets = new java.awt.Insets(44, 0, 0, 0);
        jPanel1.add(loginToggleButton, gridBagConstraints);

        signUpToggleButton.setBackground(new java.awt.Color(48, 199, 32));
        signUpToggleButton.setText("Sign Up");
        signUpToggleButton.addActionListener(new java.awt.event.ActionListener()
        {
            public void actionPerformed(java.awt.event.ActionEvent evt)
            {
                signUpToggleButtonActionPerformed(evt);
            }
        });
        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 0;
        gridBagConstraints.gridy = 0;
        gridBagConstraints.ipadx = 25;
        gridBagConstraints.ipady = 8;
        gridBagConstraints.anchor = java.awt.GridBagConstraints.NORTHWEST;
        gridBagConstraints.insets = new java.awt.Insets(44, 80, 0, 0);
        jPanel1.add(signUpToggleButton, gridBagConstraints);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
        );

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

Answer 1

不要使用setPreferredSize()。

每个 Swing 组件都会根据组件的属性确定自己的大小。在许多情况下，这将基于组件的文本。

对于没有默认文本的文本字段，您应该创建如下组件:

//emailTextField = new javax.swing.JTextField();
//passwordField = new javax.swing.JPasswordField();
emailTextField = new javax.swing.JTextField(20);
passwordField = new javax.swing.JPasswordField(10);

因此组件可以确定其首选大小以显示 20/10 个字符。 (它实际上调整自身大小以显示“W”字符)。

此外，通常不需要设置组件的最小/最大尺寸，因为除非填充单元格，否则 GridBagLayout 将遵循首选尺寸。