填充JPanel底部的空白空间

Question

我正在编写一个自定义JPanel，手动调用它MyPanel，它包含两个JLabels和两个JTextBoxes。此JPanel将用于包含使用CardLayout的其他JPanel的JFrame。 JFrame不可调整大小;其大小基于组件最多的JPanel来确定。

由于MyPanel在控件上很稀疏，我试图找出最好的布局管理器来使用。我希望标签和文本字段靠近顶部，并在底部留出所有额外空间。我相信GridBagLayout提供了让这个面板看起来像我想要的方式的功能。 MyPanel具有以下的initComponents（）方法，该方法从构造称为：

public class MyPanel extends JPanel { 

    public static void main(String[] args) { 
     JFrame frame = new JFrame("MyPanel Test"); 
     frame.add(new MyPanel(null)); 
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     frame.setSize(400, 425); 
     frame.setVisible(true); 
    } 

    public MyPanel() { 
     initComponents(); 
    } 

    private void initComponents() { 
     this.setLayout(new GridBagLayout()); 

     JLabel cardYearLabel = new JLabel("Card Year:"); 
     cardYearLabel.setFont(new Font("Tahoma", 0, 14)); // NOI18N 

     GridBagConstraints yearLabelConstraints = new GridBagConstraints(); 
     yearLabelConstraints.gridx = 0; 
     yearLabelConstraints.gridy = 0; 
     yearLabelConstraints.weightx = 1; 
     yearLabelConstraints.weighty = 1; 
     yearLabelConstraints.anchor = GridBagConstraints.WEST; 
     yearLabelConstraints.insets = new Insets(20, 50, 10, 10); 
     this.add(cardYearLabel, yearLabelConstraints); 

     this.yearTextField = new JFormattedTextField(); 
     this.yearTextField.setFormatterFactory(new DefaultFormatterFactory(new NumberFormatter(new DecimalFormat("#0")))); 
     this.yearTextField.setFont(new Font("Tahoma", 0, 14)); // NOI18N 
     this.yearTextField.setColumns(10); 
     this.yearTextField.addFocusListener(new UpdateInstructionsFocusListener("Enter card year.")); 

     GridBagConstraints yearTextFieldConstraints = new GridBagConstraints(); 
     yearTextFieldConstraints.gridx = 1; 
     yearTextFieldConstraints.gridy = 0; 
     yearTextFieldConstraints.weightx = 2; 
     yearTextFieldConstraints.weighty = 1; 
     yearTextFieldConstraints.fill = GridBagConstraints.HORIZONTAL; 
     yearTextFieldConstraints.insets = new Insets(20, 10, 10, 50); 
     this.add(this.yearTextField, yearTextFieldConstraints); 

     JLabel cardNumberLabel = new JLabel("Card Number:"); 
     cardNumberLabel.setFont(new Font("Tahoma", 0, 14)); // NOI18N 

     GridBagConstraints numberLabelConstraints = new GridBagConstraints(); 
     numberLabelConstraints.gridx = 0; 
     numberLabelConstraints.gridy = 1; 
     numberLabelConstraints.weightx = 1; 
     numberLabelConstraints.weighty = 1; 
     numberLabelConstraints.anchor = GridBagConstraints.WEST; 
     numberLabelConstraints.insets = new Insets(10, 50, 0, 10); 
     this.add(cardNumberLabel, numberLabelConstraints); 

     this.numberTextField = new JFormattedTextField(); 
     this.numberTextField.setFormatterFactory(new DefaultFormatterFactory(new NumberFormatter(new DecimalFormat("#0")))); 
     this.numberTextField.setFont(new Font("Tahoma", 0, 14)); // NOI18N 
     this.numberTextField.setColumns(10); 
     this.numberTextField.addFocusListener(new UpdateInstructionsFocusListener("Enter card number.")); 

     GridBagConstraints numberTextFieldConstraints = new GridBagConstraints(); 
     numberTextFieldConstraints.gridx = 1; 
     numberTextFieldConstraints.gridy = 1; 
     numberTextFieldConstraints.weightx = 2; 
     numberTextFieldConstraints.weighty = 1; 
     numberTextFieldConstraints.fill = GridBagConstraints.HORIZONTAL; 
     numberTextFieldConstraints.insets = new Insets(10, 10, 0, 50); 
     this.add(this.numberTextField, numberTextFieldConstraints); 

     JPanel filler = new JPanel(); 
     GridBagConstraints fillerConstraints = new GridBagConstraints(); 
     fillerConstraints.gridx = 0; 
     fillerConstraints.gridy = 2; 
     fillerConstraints.gridwidth = 2; 
     fillerConstraints.weightx = 1; 
     fillerConstraints.weighty = 100; 
     this.add(filler, fillerConstraints); 
    } 
} 

我在使用空白的JPanel填满在MyPanel底部的空的空间畏缩。有没有更好，更优雅的方式来做到这一点？ （我并没有停留在使用GridBagLayout，如果另一个标准的LayoutManager可以做到这一点，我完全可以这么做）。

Answer 1

实现此目的的一种方法是将控件放在面板中，然后将该面板添加到PAGE_START第二个面板与BorderLayout。