Java - 无法从 JComboBox 获取所选项目

Question

如果组合框中有三个项目:

123、456和789，只能得到第一个(123)，忽略其余的。

mainCombo.addPopupMenuListener(new PopupMenuListener() {

        ArrayList<Object> selectionSaver = new ArrayList<Object>();

        @Override
        public void popupMenuWillBecomeVisible(PopupMenuEvent arg0) {
            if (mainList.getSelectedValue() != null) {
                ArrayList<Object> arrayValue = mainMethods.returnArrayList(mainList.getSelectedValue());
                for (int i = 0; i < arrayValue.size(); i++) {
                mainCombo.addItem(arrayValue.get(i));
                }   
                Object lastSelected = mainCombo.getSelectedItem(); // It gets the bloody first and never the other ones, even when I select them.
                selectionSaver.add(lastSelected); // It adds the bloody first that was captured.
                System.out.println(selectionSaver); // Prints only the first, because it was selected by default.
            }
        }

        @Override
        public void popupMenuWillBecomeInvisible(PopupMenuEvent arg0) {
            mainCombo.removeAllItems();
        }

        @Override
        public void popupMenuCanceled(PopupMenuEvent arg0) {
            // TODO Auto-generated method stub

        }
    });

非常不愉快的问题。我仅在单击组合框(弹出窗口)时使用组合框，因此我此时添加其项目，然后删除它们。尽管如此，第一个/标题项从未更新，或者只是空白，并且我无法使用字段保存最后的选择状态，现在我也无法通过 ArrayList 的帮助来做到这一点。我尝试了鼠标和项目监听器，但每次都惨败，因为它总是返回第一个元素。

您是否知道如何跟踪所选内容，即使仅在弹出窗口内处理它？非常感谢您!

Answer 1

太棒了，mKorbel!我删除了弹出监听器并转到 JList，我终于让它工作了；现在它工作得很好，组合框根据 JList 完美更新，第一个项目神奇地随着组合框项目选择而更新。

出于学习目的，代码如下:

mainList.addListSelectionListener(new ListSelectionListener() {

        @Override
        public void valueChanged(ListSelectionEvent arg0) {
            int selected[] = mainList.getSelectedIndices();
            for (int i = 0; i < selected.length; i++) {
                String element = mainList.getModel().getElementAt(selected[i]);
                textItem.setText(element);
            }   
            if (arg0.getValueIsAdjusting() == true) {
                if (mainList.getSelectedValue() != null) {
                    ArrayList<Object> arrayValue = mainMethods.returnArrayList(mainList.getSelectedValue());
                    mainCombo.removeAllItems();
                    for (int i = 0; i < arrayValue.size(); i++) {
                        mainCombo.addItem(arrayValue.get(i));
                    }   
                }
            }

        }
    });