Question

我正在编写一个自定义JPanel，手动调用MyPanel，它包含两个JLabel和两个JTextBox。此JPanel将用于包含使用CardLayout的其他JPanel的JFrame。 JFrame是不可调整大小的;它的大小是根据具有最多组件的JPanel来修复的。

由于MyPanel在控件上很稀疏，我试图弄清楚要使用的最佳布局管理器。我希望标签和文本字段显示在顶部附近，底部有所有额外的空间。我相信GridBagLayout提供了让这个面板看起来像我想要的功能。 MyPanel具有以下initComponents（）方法，该方法从构造函数调用：

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);
    }
}

我畏缩使用空白的JPanel填满MyPanel底部的空白区域。有没有更好，更优雅的方式来做到这一点？（我不会停留在使用GridBagLayout。如果另一个标准的LayoutManager可以做到这一点，我会全力以赴。）

Answer 1

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

填写JPanel底部的空白区域

1 个答案: