ios – [__NSDictionaryI setObject：forKey：]：无法识别的选择器发送到实例

我试图将“dateTime”添加到我的字典中,如下所示：

Symptom Ranking: {
    5111ef19253b4a9150000000 = 1;
    5111f029253b4add4e000000 = 1;
    5111f036253b4a123d000001 = 1;
    5111f045253b4a404f000000 = 1;
}

NSLog(@"date selected: %@",[[self.datePicker date] description])

[self.results setobject:[[self.datePicker date] description] forKey:@"dateTime"];

应用程序崩溃,我得到这个：

Symptom Tracker[43134:c07] -[__NSDictionaryI setobject:forKey:]: unrecognized selector sent to instance 0x7603990
2013-02-06 08:15:58.741 Symptom Tracker[43134:c07] *** Terminating app due to uncaught exception 'NSinvalidargumentexception',reason: '-[__NSDictionaryI setobject:forKey:]: unrecognized selector sent to instance 0x7603990'
*** First throw call stack:
(0x171b012 0x1428e7e 0x17a64bd 0x170abbc 0x170a94e 0x521e 0x143c705 0x373920 0x3738b8 0x434671 0x434bcf 0x433d38 0x3a333f 0x3a3552 0x3813aa 0x372cf8 0x2652df9 0x2652ad0 0x1690bf5 0x1690962 0x16c1bb6 0x16c0f44 0x16c0e1b 0x26517e3 0x2651668 0x37065c 0x25dd 0x2505)

解决方法

你的字典是不可变的 – 它是一个NSDictionary,而不是NSMutableDictionary.解决这个问题,它可以正常工作.