如何在禁用的JComboBox上更改（顯示）所選項目？

Question

我想以編程方式更改禁用的JComboBox上顯示的所選項目。 我試過了

• 在調用setSelectedItem之前啟用它，並在之后立即禁用它
• 前者並在禁用之前調用updateUI

可能這不是故意的，但可以省去我用JLabel替換combobox的工作，因此也歡迎您提出骯臟的hack答案。

Answer 1

好吧，這似乎對我來說還行...

import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Test {

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

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridwidth = GridBagConstraints.REMAINDER;

            JComboBox cb = new JComboBox(new String[]{
                "One", "Two", "Three", "Four", "Five"
            });
            cb.setEnabled(false);
            add(cb, gbc);
            cb.setEnabled(false);

            JButton btn = new JButton("Update");
            add(btn, gbc);

            btn.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    cb.setSelectedItem("Five");
                }
            });
        }

    }

}

確保您使用的對象equal JComboBox的值