java - JList 覆盖单元格的 toString 以正确显示

Question

大家好! 我有几个问题:我如何重写 JList 的方法，我有一些 Point 数组，它们喜欢在服务器端和客户端之间行走，所以我不能只重写 Point 的 toString() 。我的逻辑告诉我，我可以在 JList 或 DefaultListModel 中做到这一点，但我找不到信息(可能我不知道如何谷歌)。那么也许有人知道怎么做？

P.s.抱歉我的英语和语法；

public class PointsList extends JPanel {
    private Extra extra;
    private JList<Point> pointsList;
    private DefaultListModel<Point> listModel;

    public PointsList(Extra extra) {
        this.extra = extra;
        setBackground(Settings.pointListBackround);
        listModel = new DefaultListModel<Point>();
        pointsList = new JList<Point>(
               //Which method i must override, to change cell toString
        };
        pointsList.getSelectionModel().addListSelectionListener(getSelectionListAction());
        setLayout(new BorderLayout());
        add(pointsList);
        setPreferredSize(new Dimension(150, 100));
    }

    private ListSelectionListener getSelectionListAction() {
        return new ListSelectionListener() {
            @Override
            public void valueChanged(ListSelectionEvent e) {
                if (e.getValueIsAdjusting()) {
                    extra.setSelectedPoint(pointsList.getSelectedValue());
                    extra.repaintCanvas();
                }
            }
        };
    }

    public void updateList() {
        listModel.removeAllElements();
        for (Map.Entry<Point, Boolean> currentPoint : extra.getPoints().entrySet()) {
            listModel.addElement(currentPoint.getKey());
        }
    }
}

我的回答:(我不想创建新类，因为这是很少的代码)

public class PointsList extends JPanel {
    private Extra extra;
    private JList<Point> pointsList;
    private DefaultListModel<Point> listModel;

    public PointsList(Extra extra) {
        this.extra = extra;
        setBackground(Settings.pointListBackround);
        listModel = new DefaultListModel<Point>();
        pointsList = new JList<Point>(listModel);
        pointsList.setCellRenderer(getRender());
        pointsList.getSelectionModel().addListSelectionListener(getSelectionListAction());
        setLayout(new BorderLayout());
        add(pointsList);
        setPreferredSize(new Dimension(150, 100));
    }

    private ListSelectionListener getSelectionListAction() {
        return new ListSelectionListener() {
            @Override
            public void valueChanged(ListSelectionEvent e) {
                if (e.getValueIsAdjusting()) {
                    extra.setSelectedPoint(pointsList.getSelectedValue());
                    extra.repaintCanvas();
                }
            }
        };
    }

    public void updateList() {
        listModel.removeAllElements();
        for (Map.Entry<Point, Boolean> currentPoint : extra.getPoints().entrySet()) {
            listModel.addElement(currentPoint.getKey());
        }
    }

    private ListCellRenderer<Point> getRender() {
        return new ListCellRenderer<Point>() {
            @Override
            public Component getListCellRendererComponent(JList<? extends Point> list, Point value, int index, boolean isSelected, boolean cellHasFocus) {
                JLabel cell = new JLabel("(" + value.x + " , " + value.y + ")");
                cell.setForeground(Color.black);
                return cell;
            }
        };
    }
}

Answer 1

i can't just override Point's toString().

您需要使用自定义渲染器。阅读Writing a Custom Renderer Swing 教程中关于如何使用列表的部分。