demo地址:https://share.weiyun.com/5KdP6lw

创建一个类SortedTime继承于NSObject
在该类中有一个方法,对传入字符串数组中的时间字符串根据时间格式进行排序(升序/降序)

+ (NSMutableArray *)sortedTimeWithTimeArray:(NSMutableArray<NSString *> *)timeArray dateFormater:(NSString *)dateFormater ascending:(BOOL)ascending;

创建一个类CustomDate,继承于NSObject，该类中有两个属性

@property (nonatomic, strong) NSString *strTime;
@property (nonatomic, strong) NSDate *dateTime;

在SortedTime.m中,该方法的实现:

+ (NSMutableArray *)sortedTimeWithTimeArray:(NSMutableArray<NSString *> *)timeArray dateFormater:(NSString *)dateFormater ascending:(BOOL)ascending
{
    NSMutableArray *arrTemp = [[NSMutableArray alloc] init];
    NSMutableArray *arrResult = [[NSMutableArray alloc] init];
    
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    NSTimeZone *timeZone = [NSTimeZone localTimeZone];
    [formatter setTimeZone:timeZone];
    
    for (NSString *timeString in timeArray)
    {
        CustomDate *dateC = [[CustomDate alloc] init];
        [formatter setDateFormat: dateFormater];
        dateC.dateTime = [formatter dateFromString:timeString];
        dateC.strTime = timeString;
        [arrTemp addObject:dateC];
    }
    
    NSSortDescriptor *sorter = [[NSSortDescriptor alloc] initWithKey:@"dateTime" ascending:ascending];
    NSMutableArray *sortDescriptors = [[NSMutableArray alloc] initWithObjects:&sorter count:1];
    NSMutableArray *sortArray = [arrTemp sortedArrayUsingDescriptors:sortDescriptors].mutableCopy;
    
    for (CustomDate *dateCustom in sortArray)
    {
        [arrResult addObject:dateCustom.strTime];
    }
    return arrResult;
}

关于NSSortDescriptor的使用,可以参考链接:
https://www.jianshu.com/p/3e9f0884be6b

使用方法:

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    NSMutableArray *arrTest = [[NSMutableArray alloc] init];
    [arrTest addObject:@"2018-11-20"];
    [arrTest addObject:@"2018-11-19"];
    [arrTest addObject:@"2018-11-7"];
    [arrTest addObject:@"2018-5-15"];
    NSLog(@"%@",[SortedTime sortedTimeWithTimeArray:arrTest dateFormater:@"yyyy-M-d" ascending:YES]);
}

输出结果:

(
    "2018-5-15",
    "2018-11-7",
    "2018-11-19",
    "2018-11-20"
)

*注:时间的格式要传正确,且时间不能重复,否则可能导致排序失败