Question

概述：
当Day类的start字段end或DayPeriod发生更改时，组合框（即每个字段一个）将对此作出反应，显示由toString()字段的方法。

问题：
虽然组合“getSelectedItem()和getSelectedIndex()确认在使用setSelectedItem方法后发生了更改，但它不可见，即旧选择仍然可见。

详细说明：
DayPeriod类包含私有Day start和Day end字段及其各自的设置者，实现PropertyChangeListener。

public class DayPeriod implements PropertyChangeListener {

    private Day                     start, end;
    private PropertyChangeSupport   propertyChangeSupport;                      

    DayPeriod () {
        setStart(new Day());
        setEnd(new Day());
        propertyChangeSupport = new PropertyChangeSupport(this);
        addPropertyChangeListener(this);
    }

    void setStart (Day newDay) {
        Day oldDay = start;
        start = newDay;
        try {
            propertyChangeSupport.firePropertyChange("dayStart", oldDay, start);
        }
        catch (NullPointerException ex) {
        }
    }

    void setEnd (Day day) {
        Day oldDay = end;
        end = day;
        try {
            propertyChangeSupport.firePropertyChange("dayEnd", oldDay, end);
        }
        catch (NullPointerException ex) {
        }
    }

    public void addPropertyChangeListener (PropertyChangeListener listener) {
        propertyChangeSupport.addPropertyChangeListener(listener);
    }

    @Override
    public void propertyChange (PropertyChangeEvent event) { // listener
        if (event.getPropertyName().equals("dayStart")) {
            Day day = (Day) event.getNewValue();
            if (getEnd().compareTo(day) < 0)
                setEnd(day);
        }
    }
}

最后的propertyChange方法只是为了确保start更改end，如果其值小于start，则Day会发生变化，即一段时间不能在它开始之前结束。

equals(Day other)课程几乎就是工作日。它实现了Comparable方法，toString()接口和public class Day implements Comparable<Day> { private DayOfWeek dayOfWeek; Day () { dayOfWeek = DayOfWeek.MONDAY; } Day (DayOfWeek day) { dayOfWeek = day; } public String toString () { return dayOfWeek.getDisplayName(TextStyle.FULL, OpeningHours.locale); } @Override public int compareTo (final Day other) { if (getDayOfWeek().compareTo(other.getDayOfWeek()) < 0) return -1; else if (getDayOfWeek().compareTo(other.getDayOfWeek()) > 0) return 1; else return 0; } DayOfWeek getDayOfWeek () { return dayOfWeek; } boolean equals (Day other) { return getDayOfWeek().equals(other.getDayOfWeek()); } }方法;一切按预期工作。

DayCombo

这里有组合框：
我在面板中创建的extends JComboBox类（propertyChange）的实例也有public class DayCombo extends JComboBox<Day> implements ItemListener, PropertyChangeListener { private DayPeriod period; private boolean isStart; { for (DayOfWeek day : DayOfWeek.values()) addItem(new Day(day)); addItemListener(this); } DayCombo (DayPeriod period, boolean isStart) { this.period = period; this.isStart = isStart; } public void itemStateChanged (final ItemEvent e) { if (e.getStateChange() == ItemEvent.SELECTED) { Day selectedDay = (Day) getSelectedItem(); if (isStart) period.setStart(selectedDay); else period.setEnd(selectedDay); } } @Override public void propertyChange (PropertyChangeEvent event) { Day selectedDay = (Day) getSelectedItem(); Day otherDay = (Day) (event.getNewValue()); String propertyName = event.getPropertyName(); if (!isStart && propertyName.equals("dayStart")) { // main focus, not working as expected setSelectedItem(otherDay); } } }方法，因此只要上述事件触发，它们就会做出反应。
在构造函数中，组合框中填充了所有可能的日期，并将其自身添加到要观察的时段。

{{1}}

我想这不是关于任何听众的，而是更多关于组合框没有刷新可见的内容。

如果需要在代码中添加更多评论，请告诉我。

JComboBox没有对setSelectedItem方法做出反应

0 个答案: