Question

编译时，我有一个空白窗口。没有元素添加到主框架。我错过了什么？

public class Gui extends JFrame {
    private JComboBox<String> box;
    private JLabel picture;
    private static String[] filename = {"pic1", "pic2.png" };
    private Icon[] pics = { new ImageIcon(getClass().getResource(filename[0])),
            new ImageIcon(getClass().getResource(filename[1])) };

    Gui() {
        super("window");
        setLayout(new FlowLayout());
        setVisible(true);
        setSize(600, 500);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        box = new JComboBox<String>(filename);
        box.addItemListener(new ItemListener() {
            public void itemStateChanged(ItemEvent e) {
                if (e.getStateChange() == ItemEvent.SELECTED) {
                    picture.setIcon(pics[box.getSelectedIndex()]);
                }
            }
        });
        picture = new JLabel(pics[0]);
        add(picture);
        add(box);
    }
}

Answer 1

可能出现的问题： 1.确保用于图片的相对或绝对路径正确。 2.在创建此类对象的位置，需要调用t.setVisible（true）。（即看看我的主要方法）

public class Gui extends JFrame {
    private JComboBox<String> box;
    private JLabel picture;
    private static String[] filename = {"C:\\Users\\..\\pic1.jpg","C\\Users\\..\\pic2.jpg" };
    private Icon[] pics = { new ImageIcon(filename[0]),
        new ImageIcon(filename[1] ) };

Gui() {
    super("window");
    setLayout(new FlowLayout());
    setVisible(true);
    setSize(600, 500);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    box = new JComboBox<String>(filename);
    box.addItemListener(new ItemListener() {
        public void itemStateChanged(ItemEvent e) {
            if (e.getStateChange() == ItemEvent.SELECTED) {
                picture.setIcon(pics[box.getSelectedIndex()]);
            }
        }
    });
    picture = new JLabel(pics[0]);
    add(picture);
    add(box);
}

public static void main(String[] args){
    Gui t = new Gui();
    t.setVisible(true);
}

如何显示从ComboBox中选择的图像

1 个答案: