iphone - 尝试使用 SBJsonWriter 设置值/键对时出错

Question

尝试设置值/键对时出现以下错误：

2011-06-21 16:21:16.727 agent[94408:207] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<SBJsonWriter 0xab31230> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key key.'

这是代码：

SBJsonWriter *writer = [[SBJsonWriter alloc] init];

[writer setValue:@"val" forKey:@"key"];

NSString *json = [writer JSONRepresentation];

NSLog([NSString stringWithFormat:@"json: @%", json]); 

Answer 1

(NSObject)即使用类别中的键值编码，

使用字典接口：导入 JSON.h 然后：

    NSMutableDictionary * dict = [NSMutableDictionary new];
    [dict setValue:@"val" forKey:@"key"];

    NSLog(@"json: %@", [dict JSONRepresentation]);

ps NSLog 接受一种格式，因此您不需要从格式中创建一个字符串来传递给它。