ios - 如何按日期对 nsmutabledictionary 进行排序

Question

我有一个 JSON 返回的 NSMutabledictionary，其中包含以下内容

OdometerStart = "9 miles";
    Size = 40;
    StartTime = "01-30-2013 2:30 PM";
    Tractor = T04;

  OdometerStart = "668 miles";
    Size = 40;
    StartTime = "01-30-2013 2:23 PM";
    Tractor = T04;

我需要按 StartTime 对其进行排序，有没有办法对其进行排序？谢谢。

Answer 1

排序的方法有很多种。这是一个:

NSMutableDictionary *dict; //dictionary to be sorted

        NSArray *sortedKeys = [dict keysSortedByValueUsingComparator: ^(id obj1, id obj2) {
            //get the key value.
            NSString *s1 = [obj1 objectForKey:@"StartTime"];
            NSString *s2 = [obj2 objectForKey:@"StartTime"];

            //Convert NSString to NSDate:
            NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
            //Set the AM and PM symbols
            [dateFormatter setAMSymbol:@"AM"];
            [dateFormatter setPMSymbol:@"PM"];
           //Specify only 1 M for month, 1 d for day and 1 h for hour
           [dateFormatter setDateFormat:@"M/d/yyyy h:mm:ss a"]; 
           NSDate *d1 = [dateFormatter dateFromString:s1];
           NSDate *d2 = [dateFormatter dateFromString:s2];
           [dataFormatter release];

            if ([d1 compare:d2] == NSOrderedAscending) 
                return (NSComparisonResult)NSOrderedAscending;
            if ([d1 compare:d2] == NSOrderedDescending)
                return (NSComparisonResult)NSOrderedDescending; 
            return (NSComparisonResult)NSOrderedSame;
        }];
        NSArray *sortedValues = [[dict allValues] sortedArrayUsingSelector:@selector(compare:)];

查看苹果文档: https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/Collections/Articles/Dictionaries.html

排序描述符苹果文档在这里: https://developer.apple.com/library/ios/#documentation/Cocoa/Conceptual/SortDescriptors/Articles/Creating.html