循环通过jComboBox

创建一个列表来跟踪添加到面板中的所有组合框,然后循环它们。例如:

List<JComboBox> list = new ArrayList<JComboBox>();

JComboBox box = new JComboBox();
panel.add(box);
list.add(box); //store reference to the combobox in list

// Later, loop over the list
for(JComboBox b: list){
    b.setSelectedIndex(0);
}

你可以在 Component 通过检查每个 组成部分 是 Container ,如果是,则对容器的子组件进行迭代,以此类推。您可以将此功能包装为 ComponentIterator ,它由层次结构中的根组件初始化。这将允许您在组件树上迭代并初始化每个组件树 JComboBox 一个特定的值。

然而 ,我不建议使用这种“通用”方法,因为随着时间的推移,随着代码的发展,它可能会产生不可预见的结果。相反,编写一个简单的工厂方法来创建和初始化 下拉框 ;例如。

private JComboBox createCombo(Object[] items) {
  JComboBox cb = new JComboBox(items);

  if (items.length > 0) {
    cb.setSelectedIndex(0);
  }

  return cb;
}

这是 成分致畸剂 在有任何用途的情况下实施:

public class ComponentIterator implements Iterator<Component> {
    private final Stack<Component> components = new Stack<Component>();

    /**
     * Creates a <tt>ComponentIterator</tt> with the specified root {@link java.awt.Component}.
     * Note that unless this component is a {@link java.awt.Container} the iterator will only ever return one value;
     * i.e. because the root component does not contain any child components.
     *
     * @param rootComponent Root component
     */
    public ComponentIterator(Component rootComponent) {
        components.push(rootComponent);
    }

    public boolean hasNext() {
        return !components.isEmpty();
    }

    public Component next() {
        if (components.isEmpty()) {
            throw new NoSuchElementException();
        }

        Component ret = components.pop();

        if (ret instanceof Container) {
            for (Component childComponent : ((Container) ret).getComponents()) {
                components.push(childComponent);
            }
        }

        return ret;
    }

    public void remove() {
        throw new UnsupportedOperationException();
    }
}