我必须按日期和时间订购约会.我有一个约会的ArrayList,并试图创建一个比较器来比较他们的日期和时间.我正在尝试使用Collections.sort方法,将其传递给Appointments的ArrayList和我创建的AppointmentComparator.在编译时,我得到了“没有合适的排序方法”.这是编译器生成的完整错误消息的链接：
http://prntscr.com/7y4qb
比较：
public class AppointmentComparator implements Comparator
{
public int compare(Appointment a, Appointment b)
{
if (a.getDay() < b.getDay())
return -1;
if (a.getDay() == b.getDay())
{
if (a.getStart() < b.getStart())
return -1;
if (a.getStart() > b.getStart())
return 1;
return 0;
}
return 1;
}
带语法错误的行：
Collections.sort(book, new AppointmentComparator());
变量book是约会的ArrayList.的ArrayList
预约书类：
import java.util.ArrayList;
import java.util.Collections;
public class AppointmentBook
{
private ArrayList book;
public AppointmentBook()
{
book = new ArrayList();
}
public void addAppointment(Appointment appt)
{
book.add(appt);
Collections.sort(book, new AppointmentComparator());
}
public String printAppointments(int day)
{
String list = "";
for (int i = 0; i < book.size(); i++)
{
if (book.get(i).getDay() == day)
{
list = list + "Appointment description: " + book.get(i).getDescription() + "\n" + "Date of Appointment: " +
book.get(i).getDay() + "\n" + "Time: " + book.get(i).getStart() + " - " + book.get(i).getEnd() + "\n" + "\n";
}
}
return list;
}
预约课程：
public class Appointment
{
private String desc;
private int day; //in format mmddyyyy
private int start; //in format hhmm
private int end; //in format hhmm
public Appointment(String description, int aptDay, int startTime, int endTime)
{
desc = description;
day = aptDay;
start = startTime;
end = endTime;
}
public String getDescription()
{
return desc;
}
public int getDay()
{
return day;
}
public int getStart()
{
return start;
}
public int getEnd()
{
return end;
}
}