Java JComboBox更改下拉箭头图像不工作

我试图更改带有自定义图像的JComboBox的下拉箭头，但代码似乎不起作用。我听从了老师的指示。我尝试了Java1.8.131和采用OpenJDK11.0.5，但结果都是一样的。下面您可以找到我使用的完整代码：

Main.java

public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, UnsupportedLookAndFeelException { 
    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
    JFrame f = new JFrame("Window");
    JPanel panel = new JPanel();
    panel.setBounds(0, 0, 400, 400);
    panel.setBackground(Color.gray);

    JComboBox<String> box = new JComboBox<>();//simple JComboBox with custom UI
    box.setPreferredSize(new Dimension(150, 30));
    box.setUI(MyBasicComboboxUI.createUI(box));

    box.addItem("BasicComboBoxUI1");
    box.addItem("BasicComboBoxUI2");
    box.addItem("BasicComboBoxUI3");

    panel.add(box);

    JButton btn = new JButton("SimpleJButton");//simple JButton with an image on it (to prove that the image loads)
    btn.setPreferredSize(new Dimension(120, 30));
    MyImageProvider imageProvider = new MyImageProvider();
    btn.setIcon(new ImageIcon(imageProvider.getImage()));
    btn.setBorder(new EmptyBorder(0, 0, 0, 0));

    panel.add(btn);
    f.add(panel);
    f.setSize(400, 400);
    f.setLayout(null);
    f.setVisible(true);
    f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
}

public class MyImageProvider {

    public Image getImage() {
        try {
            Image img = ImageIO.read(getClass().getResource("/icons/arrow.gif"));
            return img;
        } catch (IOException e) {
            System.out.println("The image was not loaded.");
        }
        return null;
    }
}

MyImageProvider.java

public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, UnsupportedLookAndFeelException { 
    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
    JFrame f = new JFrame("Window");
    JPanel panel = new JPanel();
    panel.setBounds(0, 0, 400, 400);
    panel.setBackground(Color.gray);

    JComboBox<String> box = new JComboBox<>();//simple JComboBox with custom UI
    box.setPreferredSize(new Dimension(150, 30));
    box.setUI(MyBasicComboboxUI.createUI(box));

    box.addItem("BasicComboBoxUI1");
    box.addItem("BasicComboBoxUI2");
    box.addItem("BasicComboBoxUI3");

    panel.add(box);

    JButton btn = new JButton("SimpleJButton");//simple JButton with an image on it (to prove that the image loads)
    btn.setPreferredSize(new Dimension(120, 30));
    MyImageProvider imageProvider = new MyImageProvider();
    btn.setIcon(new ImageIcon(imageProvider.getImage()));
    btn.setBorder(new EmptyBorder(0, 0, 0, 0));

    panel.add(btn);
    f.add(panel);
    f.setSize(400, 400);
    f.setLayout(null);
    f.setVisible(true);
    f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
}

public class MyImageProvider {

    public Image getImage() {
        try {
            Image img = ImageIO.read(getClass().getResource("/icons/arrow.gif"));
            return img;
        } catch (IOException e) {
            System.out.println("The image was not loaded.");
        }
        return null;
    }
}

使用12px 12px的图像：

24像素x 24像素的图像：

运行程序时的输出：

箭头上设置的工具提示正在工作。如果我使用自定义背景色也是一样的。但如果我设定了一个形象就不会了。我尝试了：*.jpg、*.gif、*.png和不同的分辨率：16x16、14x14、12x12、8x8等，但没有成功。在所有情况下，图像仅加载在SimpleJButton上，而不加载在combobox的下拉箭头按钮上

Eclipse结构：

---

你的问题是线路

JButton arrowButton = super.createArrowButton();

你应该把它改成

JButton arrowButton = new JButton();

---

背景：

super.createArrowButton（）

返回

ArrowButton

类的一个实例，该类提供自定义箭头绘制，不支持

setIcon

方法。

非常感谢，这个答案节省了我数小时的搜索时间。