Java Swing : How does using a JTable work?

Question

我正在尝试构建一个小表来显示约会。这是我到目前为止所拥有的。也许你可以给我一些提示，告诉我我做错了什么，或者该走哪条路。

            public class AppointmentTable extends JFrame{


        public static void main(String[] args) {
            JTable table = new JTable(new AppointmentTableModel(10, 6, new   ArrayList<Appointment>()));
            JScrollPane scrollPane = new JScrollPane(table);
            table.setFillsViewportHeight(true);
            AppointmentTable  frame = new AppointmentTable();
            frame.add(scrollPane);
            frame.setVisible(true);
        }
    public class AppointmentTable extends JFrame{


    public static void main(String[] args) {
        JTable table = new JTable(new AppointmentTableModel(10, 6, new ArrayList<Appointment>()));
        JScrollPane scrollPane = new JScrollPane(table);
        table.setFillsViewportHeight(true);
        AppointmentTable  frame = new AppointmentTable();
        frame.add(scrollPane);
        frame.setVisible(true);
    }
    }

    public class AppointmentTableModel extends AbstractTableModel {
        private int columns;
        private int rows;
        ArrayList<Appointment> appointments;

        public AppointmentTableModel(int columns, int rows,
                ArrayList<Appointment> appointments) {
            this.columns = columns;
            this.rows = rows;
            this.appointments = appointments;
        }

        @Override
        public int getColumnCount() {

            return columns;
        }

        @Override
        public int getRowCount() {

            return rows;
        }

        @Override
        public Object getValueAt(int rowIndex, int columnIndex) {

            return appointments.get(rowIndex).getByColumn(columnIndex);
        }
    }

public class Appointment {

    private Date date;
    private Sample sample;
    private String comment;
    private ArrayList<Action> history;

    public Appointment(Date date, Sample sample, String comment) {
        this.date = date;
        this.sample = sample;
        this.comment = comment;
        this.history = new ArrayList<Action>();
    }

    public Object getByColumn(int columnIndex) {
        switch (columnIndex) {
        case 0: return date;

        case 1: return date;

        case 2: return sample;

        case 3: return sample;

        case 4: return history;

        case 5: return comment;


        }
        return null;
    }

}
public class Action {
String action;

public Action(String act){
    this.action=act;
}

}

Answer 1

首先，您模型的 getRowCount() 方法不正确，应该是

public int getRowCount() {
  return appointments.size();
}

然后，您将一个空的约会列表传递给您的模型，因此表格不显示任何内容!

JTable table = new JTable(new AppointmentTableModel(10, 6, new ArrayList<Appointment>()));

在创建表格之前使用一些数据初始化您的列表。