Question

我正在尝试获取iOS应用程序的JSON，但继续获取NULL值..



- (id)initWithDictionary:(NSDictionary *)dictionary {
    self.name      = [dictionary valueForKey:@"name"];
    self.amount    = [NSString stringWithFormat:@"%@", 
                      [dictionary valueForKey:@"amount"]];
    self.goalId    = [dictionary valueForKey:@"id"];
    self.createdAt = [dictionary valueForKey:@"created_at"];
    self.updatedAt = [dictionary valueForKey:@"updated_at"];
    return self;
}
+ (NSArray *)findAllRemote {
    NSURL *url = [NSURL URLWithString:@"http://localhost:3000/goals.json"];
    NSError *error = nil;
    NSString *jsonString = 
    [NSString stringWithContentsOfURL:url 
                         encoding:NSUTF8StringEncoding 
                            error:&error];

    NSLog(@"my string = %@",  jsonString);

   NSMutableArray *goals = [NSMutableArray array];
   if (jsonString) {
       SBJSON *json = [[SBJSON alloc] init];    
       NSArray *results = [json objectWithString:jsonString error:&error];

       [json release];


       for (NSDictionary *dictionary in results) {
           Goal *goal = [[Goal alloc] initWithDictionary:dictionary];
           [goals addObject:goal];
           [goal release];
        }
    }
    return goals;    
}

- (id)initWithDictionary:(NSDictionary *)dictionary { self.name = [dictionary valueForKey:@"name"]; self.amount = [NSString stringWithFormat:@"%@", [dictionary valueForKey:@"amount"]]; self.goalId = [dictionary valueForKey:@"id"]; self.createdAt = [dictionary valueForKey:@"created_at"]; self.updatedAt = [dictionary valueForKey:@"updated_at"]; return self; } + (NSArray *)findAllRemote { NSURL *url = [NSURL URLWithString:@"http://localhost:3000/goals.json"]; NSError *error = nil; NSString *jsonString = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:&error]; NSLog(@"my string = %@", jsonString); NSMutableArray *goals = [NSMutableArray array]; if (jsonString) { SBJSON *json = [[SBJSON alloc] init]; NSArray *results = [json objectWithString:jsonString error:&error]; [json release]; for (NSDictionary *dictionary in results) { Goal *goal = [[Goal alloc] initWithDictionary:dictionary]; [goals addObject:goal]; [goal release]; } } return goals; }

JSON字符串看起来正确：

my string = [{“goal”：{“amount”：“100.0”，“created_at”：“2011-08-20T00：55：34Z”，“id”：1，“name”：“User” “的updated_at”： “2011-08-20T00：55：34Z”}}，{ “目标”：{ “量”： “200.0”， “created_at”： “2011-08-20T00：56：48Z”，” ID “：2”，名称 “：” 用户2" ， “的updated_at”： “2011-08-20T00：56：48Z”}}，{ “目标”：{ “量”： “19999.0”， “created_at”：” 2011-08-20T19：15：10Z“，”id“：3，”name“：”这是我的目标“，”updated_at“：”2011-08-20T19：15：10Z“}}，{”目标“ ：{ “量”： “0.0”， “created_at”： “2011-08-20T20：46：44Z”， “ID”：4 “名称”： “目标”， “的updated_at”：“2011-08-20T20 ：46：44Z“}}]

我想遗失一些基本的东西......

更新：

这是一行返回NULL（来自另一个类）：

goal.name 和 goal.amount 是空的..

Answer 1

这可能不属于您的问题，但您应该通过继承来调用[self init]（或更重要的是，[super init]）：

- (id)initWithDictionary:(NSDictionary *)dictionary {
    if (self = [self init]) {
      self.name      = [dictionary valueForKey:@"name"];
      self.amount    = [NSString stringWithFormat:@"%@", 
                      [dictionary valueForKey:@"amount"]];
      self.goalId    = [dictionary valueForKey:@"id"];
      self.createdAt = [dictionary valueForKey:@"created_at"];
      self.updatedAt = [dictionary valueForKey:@"updated_at"];
    }
    return self;
}

此外：

    for (NSDictionary *dictionary in results) {
       Goal *goal = [[Goal alloc] initWithDictionary:
          [dictionary objectForKey:@"goal"]];
       [goals addObject:goal];
       [goal release];
    }

第3行的主要变化为[dictionary objectForKey:@"goal"]。

JSON数组是具有单个goal成员的对象，具有initWithDictionary方法正在查找的属性。

JSON解析返回null到iOS（json字符串看起来正确）

1 个答案: