objective-c - 如何检查传入的 JSON feed 是否包含单个或多个记录？

Question

我必须在 iOS 上解析此 JSON。

{
"log_by_dates": {
    "logs": [
        {
            "date": "Wednesday 5 December 2012",
            "exercises": "0",
            "workouts": "0",
            "log_entries": "0"
        },
        {
            "date": "Tuesday 4 December 2012",
            "exercises": "4",
            "workouts": "2",
            "log_entries": "7"
        }
    ]
 }
}

我编写了以下代码来解析它；

NSArray *logs = [[(NSDictionary*)results objectForKey:@"log_by_dates"] objectForKey:@"logs"];
        for (NSDictionary *aLog in logs) {
            Log *newLog = [[Log alloc] initWithDate:[aLog objectForKey:@"date"]               withExercises:[aLog objectForKey:@"exercises"]
                                       withWorkouts:[aLog objectForKey:@"workouts"]];
            if (!data) {
               data = [[NSMutableArray alloc] init];
            }

但问题是，有时我会得到这样的 JSON 值；

{

"log_by_dates": {
    "logs":
        {
            "date": "Wednesday 5 December 2012",
            "exercises": "0",
            "workouts": "0",
            "log_entries": "0"
        }
  }
} 

这使得我的代码崩溃。

请指导我，在解析之前我使用哪个 if() else 条件来检查传入的 JSON 对象是否包含单个记录的多个记录，以便我编写适当的代码来处理字典或数组。谢谢，

Answer 1

请像这样更新您的代码。

NSArray *logs = [[(NSDictionary*)results objectForKey:@"log_by_dates"] objectForKey:@"logs"];
if([logs isKindOfClass:[NSArray class]]) {
    for (NSDictionary *aLog in logs) {
        Log *newLog = [[Log alloc] initWithDate:[aLog objectForKey:@"date"]               withExercises:[aLog objectForKey:@"exercises"]
                                   withWorkouts:[aLog objectForKey:@"workouts"]];
        if (!data) {
            data = [[NSMutableArray alloc] init];
        }
    }
}
else if([logs isKindOfClass:[NSDictionary class]]) {
    NSDictionary *aLog = (NSDictionary *)logs;
    Log *newLog = [[Log alloc] initWithDate:[aLog objectForKey:@"date"]               withExercises:[aLog objectForKey:@"exercises"]
                               withWorkouts:[aLog objectForKey:@"workouts"]];
    if (!data) {
        data = [[NSMutableArray alloc] init];
    }
}