获取每月的天数
第一种方法，自己写方法判断：
//是不是闰年
private BooleanisRunYear(int year) {
return (year %4 ==0) && (year %100 !=0) || (year %400 ==0);
}
//是不是二月
private BooleanisFebruary(int month) {
return month ==2;
}
//是不是30天的月份
private BooleanisHasThirtyDays(int month) {
return month ==4 || month ==6 || month ==9 || month ==11;
}
private ArrayList getDayList() {
int nowYear = Integer.valueOf(yearList.get(yearSelectIndex));
int nowMonth = Integer.valueOf(monthList.get(monthSelectIndex))-1;
ArrayList dayList =new ArrayList<>();
int maxDay;
if (!isRunYear(nowYear) && isFebruary(nowMonth)) {
maxDay =28;
}else if (isRunYear(nowYear) && isFebruary(nowMonth)) {
maxDay =29;
}else if (isHasThirtyDays(nowMonth)) {
maxDay =30;
}else {
maxDay =31;
}
for (int i =01; i <= maxDay; i++) {
dayList.add(getTwoNumber(i +""));
}
return dayList;
}
第二种方法，用Calendar：
Map<Integer, ArrayList<String>> DAYS = new HashMap<>()；
明显第二种更好用！
