objective-c - 在 NSDictionary 中获取值

Question

我想从 NSDictionary 中获取值。我想根据代码键控制“代码”键，我会得到数据值。当我尝试不同的方法时收到错误消息。

错误信息

2011-08-11 12:45:21.549 AOK[6312:207] -[__NSArrayM getObjects:andKeys:]: unrecognized selector sent to instance 0x5e138b0 2011-08-11 12:45:21.550 AOK[6312:207] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSArrayM getObjects:andKeys:]: unrecognized selector sent to instance 0x5e138b0' * Call stack at first throw:

NS字典

(
        {
        Omschrijving = "ADDD";
        Ophaaldata =         {
            Datum =             (
                "2011-07-04",
                "2011-07-11",
                "2011-07-18",
                "2011-07-25"
            );
        };
    },
        {
        Omschrijving = "BBBB";
        Ophaaldata =         {
            Datum =             (
                "2011-07-05",
                "2011-07-12",
                "2011-07-19",
                "2011-07-26"
            );
        };
    },
        {
        Omschrijving = "KKKK";
        Ophaaldata =         {
            Datum =             (
                "2011-07-07",
                "2011-07-14",
                "2011-07-21",
                "2011-07-28"
            );
        };
    },
        {
        Omschrijving = "LLLLL";
        Ophaaldata =         {
            Datum =             (
                "2011-07-01",
                "2011-07-08",
                "2011-07-15",
                "2011-07-22",
                "2011-07-29"
            );
        };
    },
        {
        Omschrijving = "MMMMM";
        Ophaaldata =         {
            Datum =             (
                "2011-07-01",
                "2011-07-15",
                "2011-07-29"
            );
        };
    },
        {
        Code = POP;
        Omschrijving = "FFFF";
        Ophaaldata =         {
            Datum = "2011-07-12";
        };
    },
        {
        Code = 00;
        Omschrijving = "SSSS";
        Ophaaldata =         {
            Datum =             (
                "2011-07-14",
                "2011-07-27"
            );
        };
    },
        {
        Code = 01;
        Omschrijving = "CCCCC";
        Ophaaldata =         {
            Datum =             (
                "2011-07-06",
                "2011-07-20"
            );
        };
    }
)

Answer 1

您显示的是 NSDictionaries 的 NSArray，每个包含一个带有描述 (Omschrijving) 的 NSString 和一个带有一个键 (Datum) 的 NSDictionary (Ophaaldata)，这是一个日期数组。如果您将 Objects:andKeys: 发送到 NSArray，它将不起作用。

这些是您如何获取单个项目的几个示例:

NSArray          *dicts = ...; // wherever you get the array
  NSDictionary   *mijnDict = [dicts objectAtIndex: n];
    NSString     *omschrijving = [mijnDict objectForKey: @"Omschrijving"];
    NSDictionary *ophaaldata = [mijnDict objectForkey: @"Ophaaldata"];
      NSArray    *datum = [ophaaldata objectForkey: @"Datum"];
        NSString *eersteDatum = [datum objectAtIndex: 0];

这些只是您如何处理这些项目的示例。但这是您的输出显示的结构。无论如何，其他任何东西都是无用的，因为字典只能包含每个键一次。我对代码进行了一些格式化，因此您可以更好地看到结构。