如何让我的 label 和组合框在 java 中显示为垂直而不是水平？ 我尝试将布局设置为 null 但它隐藏了 label

Question

public PetrolApplication() {

       setLayout(new FlowLayout());
           add(label);
           add(label2);
       Combo1 = new JComboBox(Arraycities);
       Combo1.setBounds(50, 50, 100, 20);

Answer 1

Use a different layout manager - see A Visual Guide to Layout Managers

import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;

public class Test {
    public static void main(String[] args) {
        new Test();
    }

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            setBorder(new EmptyBorder(16, 16, 16, 16));
            setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.insets = new Insets(4, 4, 4, 4);
            gbc.anchor = GridBagConstraints.LINE_START;
            gbc.gridx = 0;
            gbc.gridy = 0;
            gbc.gridwidth = GridBagConstraints.REMAINDER;

            add( new JLabel("I'm assuming you want something"), gbc);

            gbc.anchor = GridBagConstraints.LINE_END;
            gbc.gridy = 1;
            gbc.gridwidth = 1;
            add(new JLabel("Please make a selection"), gbc);

            DefaultComboBoxModel<String> model = new DefaultComboBoxModel<String>();
            model.addElement("This is not what you are looking for");
            model.addElement("This is something else");
            model.addElement("Not what you think");

            gbc.anchor = GridBagConstraints.LINE_START;
            gbc.gridx++;

            add(new JComboBox<String>(model));
        }

    }
}