Get the array list of the previous n days and the previous and subsequent days of the current time, and cycle through each day

Recently, a requirement appeared in the project , Before and after the current date N God choose , Get date

import java.text.DateFormat;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collections;
import java.util.Date;
import java.util.List;

----------------------------------------------------------------------------------- 

String afterTime;
String fetureTime;
List<String> listDatefan;

stay viewCreate The following code is written in this method

DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
afterTime = df.format(new Date().getTime() - 15 * 24 * 60 * 60 * 1000);// Before 15 God ,
fetureTime = df.format(new Date().getTime() + 15 * 24 * 60 * 60 * 1000);// future 15 God 
String nowTime = df.format(new Date());// current time 
handleCirculationDate(fetureTime, afterTime);
binding.tvTime.setSelected(true);

listDatefan = new ArrayList<>();
// trans 
Collections.reverse(listDate);
for (String n : listDate) {
    listDatefan.add(n);
}

 

 

 

List<String> listDate;

public List<String> handleCirculationDate(String fetureTime, String afterTime) {
    listDate = new ArrayList<>();
    SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");// Date format 
    try {
        Date startDate = dateFormat.parse(afterTime);// Before 
        Date endDate = dateFormat.parse(fetureTime);// future 
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(startDate);// Previous 
        while (calendar.getTime().before(endDate)) {
            listDate.add(dateFormat.format(calendar.getTime()));
            calendar.add(Calendar.DAY_OF_MONTH, 1);
        }
        return listDate;
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}