Question

我试图处理Facebook JSON数据并将其转换为NSMutable词典，但是当我尝试打印数据时，我得到（null）。虽然当我尝试计算时，我会得到一个数字。

User_likes是全局定义的NSMutableDictionary。我在这一行得到（null）：

NSLog(@"User likes: %@", user_likes);

这是我的代码：

NSString *query =
 @"SELECT page_id, type FROM page_fan WHERE uid = me() ";
 // Set up the query parameter
 NSDictionary *queryParam = @{ @"q": query };
 // Make the API request that uses FQL
 [FBRequestConnection startWithGraphPath:@"/fql"
 parameters:queryParam
 HTTPMethod:@"GET"
 completionHandler:^(FBRequestConnection *connection,
 id results,
 NSError *error) {
 if (error) {
 NSLog(@"Error: %@", [error localizedDescription]);
 } else {

 user_likes = [NSJSONSerialization JSONObjectWithData:results options:kNilOptions error:&error];
 NSLog(@"User likes: %@", user_likes);

 NSInteger* n_user_likes = [results count];
 NSInteger* n_user_likes2 = [user_likes count];

 NSLog(@"n user likes %qi", n_user_likes);
 NSLog(@"n user likes2 %qi", n_user_likes2);

 id val = nil;
 id values = [[user_likes allKeys] objectAtIndex:0 ];
 NSLog(@"values id %@", values);

当我打印结果时，我从Facebook获得了大量数据，这是一个样本：

data =     (
                {
            "page_id" = 253370381511811;
            type = "PUBLIC FIGURE";
        },
                {
            "page_id" = 148389618201;
            type = "LOCAL BUSINESS";
        },
                {
            "page_id" = 213631462169238;
            type = COMMUNITY;
        },
                {
            "page_id" = 162297750451425;
            type = "NON-PROFIT ORGANIZATION";
        },
                {
            "page_id" = 503620106320217;
            type = "MEDIA/NEWS/PUBLISHING";
        },

Answer 1

你不能直接做

user_likes = [NSJSONSerialization JSONObjectWithData:results options:kNilOptions error:&error];

您需要首先使用results中的数据创建一个字典，如下所示：

    NSDictionary *dictionary = [NSDictionary dictionaryWithJSONData:results]; 
    user_likes = [NSString stringWithFormat:@"%d",[[dictionary objectForKey:@"value_of_the_likes"] intValue]];
    NSLog(@"%@",user_likes);
    NSLog(@"%@",dictionary);

修改

请为您的项目创建此类，并在需要使用它的类中导入。

#import <Foundation/Foundation.h> @interface NSDictionary (JSONExtensions) +(NSDictionary*)dictionaryWithJSONData:(NSData*)data; -(NSData*)JSONValue; -(NSString*)JSONString; @end @implementation NSDictionary(JSONExtensions) +(NSDictionary*)dictionaryWithJSONData:(NSData*)data{ NSError *error = nil; NSDictionary *result = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error]; if(error){ NSLog(@"%@",error); return nil; }; return result; } -(NSData*)JSONValue{ NSError *error = nil; NSData *result = [NSJSONSerialization dataWithJSONObject:self options:kNilOptions error:&error]; if(error){ NSLog(@"%@",error); return nil; }; return result; } -(NSString*)JSONString{ return [[NSString alloc] initWithData:self.JSONValue encoding:NSUTF8StringEncoding]; } @end

希望它可以帮到你。

Answer 2

也许你忘了设置选项：

NSJSONReadingOptions options = NSJSONReadingAllowFragments | NSJSONReadingMutableContainers | NSJSONReadingMutableLeaves;

user_likes = [NSJSONSerialization JSONObjectWithData:results options:options error:&error];

我希望这对你有用！

<强>更新

检查一下： NSJsonSerialzation not parsing results from Facebook - Cocoa error 3840

如果有帮助，请告诉我！

操纵Facebook / JSON数据

2 个答案: