如何将JSON序列化数据转换为NSDictionary

Question

我用过这种方法,

NSDictionary *jsonObject=[NSJSONSerialization 
       JSONObjectWithData:jsonData 
                  options:NSJSONReadingMutableLeaves 
                    error:nil];
NSLog(@"jsonObject is %@",jsonObject);

它打印"jsonObject为null".
"error:nil"有问题吗？
我没有使用任何网址或连接方法.
我有一个json文件,我想在表中显示它.

Answer 1

请尝试以下代码.

NSError* error;
NSDictionary* json = [NSJSONSerialization JSONObjectWithData:responseData
                                                     options:kNilOptions 
                                                       error:&error];

NSArray* latestLoans = [json objectForKey:@"loans"];

NSLog(@"loans: %@", latestLoans);

Answer 2

万一有人在这里看到快速代码:

NSData到NSDictionary

let dictionary:NSDictionary = NSKeyedUnarchiver.unarchiveObjectWithData(jsonData)! as NSDictionary

NSData到NSString

let resstr = NSString(data: res, encoding: NSUTF8StringEncoding)

Answer 3

检查你的json输入,你的根元素既不是字典也不是数组？文档说明在这种情况下你必须指定NSJSONReadingAllowFragments作为选项.

#import <Foundation/Foundation.h>

int main(int argc, char *argv[]) {
    NSAutoreleasePool *p = [[NSAutoreleasePool alloc] init];

    NSData *jsonData = [@"{ \"key1\": \"value1\" }" dataUsingEncoding:NSUTF8StringEncoding];
    NSDictionary *jsonObject=[NSJSONSerialization 
           JSONObjectWithData:jsonData 
                      options:NSJSONReadingMutableLeaves 
                        error:nil];
    NSLog(@"jsonObject is %@",jsonObject);

    [p release];
}

输出:

2012-09-26 16:06:51.610 Untitled[19164:707] jsonObject is {
    key1 = value1;
}