如何使组件跨越GridBagLayout中的多个单元格

Question

我必须为学校做这个:

这是我到目前为止的代码:

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

public class AddressBookGui1 extends JFrame {
public AddressBookGui1(){

    GridBagLayout gbl = new GridBagLayout();
    GridBagConstraints gbc = new GridBagConstraints();
    setLayout(gbl);

    JLabel label;
    JButton button;
    JTextField textField;
    JTextArea textArea = new JTextArea(10, 20);

    gbc.weightx = 1;
    label = new JLabel("text");
    gbc.fill = GridBagConstraints.HORIZONTAL;
    gbc.gridx = 0;
    gbc.gridy = 0;
    add(label ,gbc);

    textField = new JTextField();
    gbc.weightx = 1;
    gbc.fill = GridBagConstraints.HORIZONTAL;
    gbc.gridx = 1;
    gbc.gridy = 0;
    add(textField ,gbc);

    label = new JLabel("text");
    gbc.weightx = 1;
    gbc.fill = GridBagConstraints.HORIZONTAL;
    gbc.gridx = 0;
    gbc.gridy = 1;
    gbc.gridwidth = 1;
    add(label ,gbc);

    textField = new JTextField();
    gbc.weightx = 1;
    gbc.fill = GridBagConstraints.HORIZONTAL;
    gbc.gridx = 1;
    gbc.gridy = 1;
    gbc.gridwidth = 2;
    add(textField, gbc);

    label = new JLabel("text");
    gbc.weightx = 1;
    gbc.fill = GridBagConstraints.HORIZONTAL;
    gbc.gridx = 0;
    gbc.gridy = 2;
    gbc.gridwidth = 1;
    add(label ,gbc);

    textField = new JTextField();
    gbc.weightx = 1;
    gbc.fill = GridBagConstraints.HORIZONTAL;
    gbc.gridx = 1;
    gbc.gridy = 2;
    gbc.gridwidth = 2;
    add(textField, gbc);

    label = new JLabel("text");
    gbc.weightx = 1;
    gbc.anchor = GridBagConstraints.FIRST_LINE_START;
    gbc.fill = GridBagConstraints.HORIZONTAL;
    gbc.gridx = 0;
    gbc.gridy = 3;
    gbc.gridwidth = 1;
    add(label ,gbc);



    gbc.weightx = 1;
    gbc.fill = GridBagConstraints.HORIZONTAL;
    gbc.anchor = GridBagConstraints.CENTER;
    gbc.gridwidth = 2;
    gbc.gridx = 1;
    gbc.gridy = 3;

    add(textArea, gbc);

    gbc.weightx = 1;
    button = new JButton("text");
    gbc.fill = GridBagConstraints.HORIZONTAL;
    gbc.gridwidth = 1;
    gbc.gridx = 0;
    gbc.gridy = 4;
    add(button ,gbc);

    gbc.weightx = 1;
    button = new JButton("text");
    gbc.fill = GridBagConstraints.HORIZONTAL;
    gbc.gridx = 3;
    gbc.gridy = 4;
    add(button ,gbc);



}
public static void main(String[] args){
  AddressBookGui1 frame = new AddressBookGui1();
  frame.setTitle("Address Book");
  frame.setSize(400, 300);
  frame.setLocationRelativeTo(null);
  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  frame.setVisible(true); 
}

}

(我仍然需要处理填充和插入.我已经让这些工作在一个更简单的程序中,所以我想我已经掌握了这些东西)

我已经尝试了GridBagLayout Oracle教程,但我不确定我做错了什么.有人可以帮助我让它看起来更像是应该的吗？特别是使文本字段和文本区域跨越2个单元格.

Answer 1

我注意到你的代码很少.

• 不要使用setSize()JFrame.这会导致异常行为.相反,让帧大小根据其组件的大小.如果您希望框架更大,请调整框架的大小,而不是框架内的组件.如果您确实要调整大小,则可以使用setpreferredSize或覆盖组件的getpreferredsize,因为GridBagLayout是尊重组件的preferredSize的布局管理器之一.使用pack()去除不必要的空间.

• 不要扩展JFrame,使您的UI类具有主面板并在其中添加所有组件.为该面板提供一个getter(例如 getUI()),用于提取该类的UI.

• 无论什么时候将GridBagConstraints对象应用于另一个组件,都要重新实例化.这样它更具可读性.

• 使用insets在组件周围放置填充.

• 不要对不同的组件重复使用相同的引用;

• 使用初始线程

• 这不是标准的,但我发现GridBagLayout在设置gbc的约束时,按照字母顺序进行操作时,它确实非常有用.

为了解决您的问题,这里是修改后的代码,其中包含我所指出的关于应用的内容.

public class AddressBook {

    private JPanel pnlMain;

    public AddressBook() {
        pnlMain = new JPanel();
        pnlMain.setLayout(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();

        JLabel lblName = new JLabel("Name");
        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.gridx = 0;
        gbc.gridy = 0;
        gbc.insets = new Insets(0, 10, 0, 0);
        gbc.weightx = 1;
        pnlMain.add(lblName, gbc);

        JTextField txtName = new JTextField();
        gbc = new GridBagConstraints();
        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.gridwidth = 3;
        gbc.gridx = 1;
        gbc.gridy = 0;
        gbc.insets = new Insets(5, 0, 0, 10);
        gbc.weightx = 1;
        pnlMain.add(txtName, gbc);

        JLabel lblPhone = new JLabel("Phone");
        gbc = new GridBagConstraints();
        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.gridwidth = 1;
        gbc.gridx = 0;
        gbc.gridy = 1;
        gbc.insets = new Insets(0, 10, 0, 0);
        gbc.weightx = 1;
        pnlMain.add(lblPhone, gbc);

        JTextField txtPhone = new JTextField();
        gbc = new GridBagConstraints();
        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.gridwidth = 3;
        gbc.gridx = 1;
        gbc.gridy = 1;
        gbc.insets = new Insets(5, 0, 0, 10);
        gbc.weightx = 1;
        pnlMain.add(txtPhone, gbc);

        JLabel lblEmail = new JLabel("Email");
        gbc = new GridBagConstraints();
        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.gridwidth = 1;
        gbc.gridx = 0;
        gbc.gridy = 2;
        gbc.insets = new Insets(0, 10, 0, 0);
        gbc.weightx = 1;
        pnlMain.add(lblEmail, gbc);

        JTextField txtEmail = new JTextField();
        gbc = new GridBagConstraints();
        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.gridwidth = 3;
        gbc.gridx = 1;
        gbc.gridy = 2;
        gbc.weightx = 1;
        gbc.insets = new Insets(5, 0, 0, 10);
        pnlMain.add(txtEmail, gbc);

        JLabel lblAddress = new JLabel("Address");
        gbc = new GridBagConstraints();
        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.gridwidth = 1;
        gbc.gridx = 0;
        gbc.gridy = 3;
        gbc.insets = new Insets(0, 10, 0, 0);
        gbc.weightx = 1;
        pnlMain.add(lblAddress, gbc);

        JTextArea txtAreaAddress = new JTextArea(10, 20);
        JScrollPane pane = new JScrollPane(txtAreaAddress);
        gbc = new GridBagConstraints();
        gbc.anchor = GridBagConstraints.NORTH;
        gbc.fill = GridBagConstraints.BOTH;
        gbc.gridwidth = 3;
        gbc.gridx = 1;
        gbc.gridy = 3;
        gbc.insets = new Insets(5, 0, 0, 10);
        gbc.weightx = 1;
        pnlMain.add(pane, gbc);

        JButton btnSave = new JButton("Save");
        gbc = new GridBagConstraints();
        gbc.anchor = GridBagConstraints.WEST;
        gbc.fill = GridBagConstraints.NONE;
        gbc.gridwidth = 1;
        gbc.gridx = 0;
        gbc.gridy = 4;
        gbc.insets = new Insets(10, 10, 10, 0);
        gbc.weightx = 1;
        pnlMain.add(btnSave, gbc);

        JButton btnCancel = new JButton("Cancel");
        gbc = new GridBagConstraints();
        gbc.anchor = GridBagConstraints.EAST;
        gbc.gridwidth = 1;
        gbc.gridx = 3;
        gbc.gridy = 4;
        gbc.insets = new Insets(10, 0, 10, 10);
        gbc.weightx = 1;
        pnlMain.add(btnCancel, gbc);

    }

    public JPanel getUI(){
        return pnlMain;
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame("Address Book");
                frame.getContentPane().add(new AddressBook().getUI());
                frame.setLocationRelativeTo(null);
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.pack();
                frame.setVisible(true);
            }
        });
    }

}

Answer 2

gbc.gridwidth是允许组件跨越多个列的参数.例如,如果您有3列和4行,并且您希望标签占据完整的顶行,则需要为标签指定第一个单元格.并设置gbc.gridwidth = 3;