Java

Question

我的 appointmentViewWeeks 构造函数从其他类接收参数并创建一个 GUI。我如何在不知道 year 和 month 的值的情况下从我的 main 方法调用它？

public class appointmentViewWeeks extends Frame{

    public appointmentViewWeeks(String year,String month){

        List<LocalDate> mondays = new ArrayList<LocalDate>();
        Month m = Month.valueOf(monthIntToString(month).toUpperCase());

        LocalDate date = Year.of(Integer.valueOf(year)).atMonth(m).atDay(1).
             with(TemporalAdjusters.firstInMonth(DayOfWeek.MONDAY));
        Month mi = date.getMonth();
        while (mi == m) {
            mondays.add(date);
            date = date.with(TemporalAdjusters.next(DayOfWeek.MONDAY));
            mi = date.getMonth();
        }
        String[] mondaysList = mondays.toArray(new String[0]);

        JComboBox mondayList = new JComboBox(mondaysList);
        JLabel welcome = new JLabel("Please choose a monday in "+month+"/"+year);

        Container contentPane = getContentPane();
        contentPane.add(mondayList);
        contentPane.add(welcome);
    }

    public String monthIntToString(String month) {
         return new DateFormatSymbols().getMonths()[Integer.valueOf(month)-1];
    }

    public static void main(String[] args) {

        //windows feel and look
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (ClassNotFoundException | 
            InstantiationException | 
            IllegalAccessException | 
            UnsupportedLookAndFeelException e) {
                e.printStackTrace();
            }
        appointmentViewWeeks view = new appointmentViewWeeks();
        view.setVisible(true);
    }
}

Answer 1

您必须传入年份和月份来创建它（或仅传入两个 Strings），除非您添加第二个不带 String 参数的构造函数：

public appointmentViewWeeks() {
    //Code to create the object without using the String parameters...
    //Maybe just call your original constructor with some default values?
}

您还可以获取当前的年份和月份，并使用您当前的构造函数创建它：

LocalDateTime date = LocalDateTime.now();
appointmentViewWeeks view = new appointmentViewWeeks(String.valueOf(date.getYear()),
                                                        String.valueOf(date.getMonth()));

Java - 显示摆动 GUI

Java - Display swing GUI

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