下拉列表中的JComboBox导航选择该项目

Question

这是我的第一个问题，我真的很抱歉我的英语。我不想在JComboBox的下拉列表中导航，显示＆＃34; JComboBox主要字段中的所选项目＆＃34; （对不起，不知道怎么称呼它，看图像）。

当我在列表中导航时会发生这种情况：

但我想要这样的事情：

当我按Enter或点击项目时，它会出现在主要字段中。

这是我的代码：

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

public class ComboTest {

JFrame frame;
JPanel panel;
String[] choices = new String[]{
        "Java",
        "Python",
        "C++",
        "PHP",
        "Perl"
};
JComboBox<String> comboBox = new JComboBox<>(choices);
JTextComponent textComponent;

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

public ComboTest() {

    frame = new JFrame();
    panel = new JPanel();
    textComponent = (JTextComponent) comboBox.getEditor().getEditorComponent();

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(300, 150);
    frame.setResizable(false);

    panel.setLayout(new FlowLayout());

    comboBox.setEditable(true);
    comboBox.setSelectedItem(null);

    panel.add(comboBox);
    frame.add(panel);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
}
}

Answer 1

试试此代码块

   comboBox.addPopupMenuListener(new PopupMenuListener() {

        @Override
        public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
            //when Popupmenu is visible, remove the combobox editor text 
            comboBox.getEditor().setItem(null);

        }

        @Override
        public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
        }

        @Override
        public void popupMenuCanceled(PopupMenuEvent e) {
        }
    });

Answer 2

感谢zilk。你的回答帮我解决了这个问题。听众addPopupMenuListener对我不起作用。但当我将addPopupMenuListener更改为addItemListener时，一切正常。

comboBox.addItemListener(new ItemListener() {
        @Override
        public void itemStateChanged(final ItemEvent itemEvent) {
            comboBox.getEditor().setItem(null);
            comboBox.getEditor().getEditorComponent().addKeyListener(new KeyAdapter() {
                @Override
                public void keyPressed(KeyEvent e) {
                    super.keyPressed(e);
                    if(e.getKeyCode() == KeyEvent.VK_ENTER)
                    {
                        comboBox.getEditor().setItem(itemEvent.getItem());
                    }
                }
            });
        }
    });