如何在 JPanel.getComponents() 中循环时获取 JButton 属性

Question

我有一个JPanel，里面装满了JButtons。

void addMealsMenuBarTitles() {
    JToggleButton test;
    int i=0;
    for (Categoria c: categories.categorias) {
        test = new JToggleButton(c.categoria);
        test.setForeground(Color.white);
        test.setBackground(new Color(52, 152, 219));
        test.setSize(new Dimension(menuMealsBar.getWidth()/categories.categorias.size(), menuMealsBar.getHeight()));
        test.setLocation(i++*(test.getWidth()), 0);
        menuMealsBar.add(test);
    }
}

我想做的是在循环遍历该 JPanel 的组件时访问 JButton 的属性（边框）

void addClickEventCategories() {
    for (Component jtb: menuMealsBar.getComponents())
        jtb.addMouseListener(new MouseListener() {
        @Override
        public void mouseClicked(MouseEvent e) {
            //jtb.setBorder(BorderFactory.createMatteBorder(0, 0, 5, 0, Color.white));
        }
        @Override public void mousePressed(MouseEvent e) {}
        @Override public void mouseReleased(MouseEvent e) {}
        @Override public void mouseEntered(MouseEvent e) {}
        @Override public void mouseExited(MouseEvent e) {}
    });
}

我得到的错误是组件没有边框属性（显然）...我怎样才能解决这个问题？

Answer 1

你可能应该使用更像...

for (Component comp: menuMealsBar.getComponents()) {
    if (comp instanceof JToggleButton) {
         JToggleButton jtb = (JToggleButton)comp;

因为你不应该对容器实际包含的内容做出假设（你会在很多时候感到惊讶;)）

另一种解决方案可能是在mouseClicked方法中执行类似操作

@Override
public void mouseClicked(MouseEvent e) {
    Component comp = e.getComponent();
    if (comp instanceof JToggleButton) {
        JToggleButton jtb = (JToggleButton)comp;
        jtb.setBorder(BorderFactory.createMatteBorder(0, 0, 5, 0, Color.white));
    }
}

Answer 2

    @Override
    public void mouseClicked(MouseEvent e) {
        //jtb.setBorder(BorderFactory.createMatteBorder(0, 0, 5, 0, Color.white));
    }

您可以从 MouseEvent 中获取组件：

    @Override
    public void mouseClicked(MouseEvent e) {
        JToggleButton button = (JToggleButton)e.getSource();
        button.setBorder(BorderFactory.createMatteBorder(0, 0, 5, 0, Color.white));
    }