如何使用web url解析ios中的json

嗨，我从外部源获取json并在ios中解析它。我的代码在下面

注=json和cats变量为NSArray

    NSURL * url = [NSURL URLWithString:@"http://myurl.json"];
    NSData * data = [NSData dataWithContentsOfURL:url];

    json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];

    cats = [[NSMutableArray alloc] init];

    for (int i=0; i < json.count; i++) {
        NSString * CatId = [[json objectAtIndex:i] objectForKey:@"id"];
        NSString * CatName = [[json objectAtIndex:i] objectForKey:@"name"];
        NSString * CatIcon = [[json objectAtIndex:i] objectForKey:@"icon"];
        categories * cat = [[categories alloc] initWithCId:CatId andCName:CatName andCIcon:CatIcon];

        [cats addObject:cat];

NSURL*url=[NSURL URLWithString:@”http://myurl.json"];
NSData*data=[NSData dataWithContentsOfURL:url]；
json=[NSJSONSerialization JSONObjectWithData:数据选项：kNilOptions错误：nil]；
cats=[[NSMutableArray alloc]init]；
for（int i=0；i

json就在这里

{“categories”：[{“id”：1，“name”：“Healthcare”，“icon”：“/icons/images/65/original_56.png？1386745569”}，{“id”：10，“name”：“Mall”，“icon”：“/icons/images/60/original_51.png？1386745369”}，{“id”：11，“name”：“tauphq”，“icon”：/icons/images：13，“名称”：“SPA”，“图标”：“/icons/images/48/original_39.png？1386745093”}，{“id”：14，“name”：“ATM”，“icon”：“/icons/images/22/original_13.png？138674578”}，{“id”：15，“name”：“Travel”，“icon”：“/images/12/original_3.png？138674393”}，{“id”：16，“name”：“游戏区”，“icon”：“/icons/images/68/original_59.png？1386745626”}，{“id”：17，“name”学术图标“：”“/icons/images/10/original_1.png？138674264”}，{“id”：18，“name”：“Textile”，“icon”：“/icons/images/46/original_37.png？13867445050”}

试试这个：

NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
json = [dict objectForKey:@"categories"];

---

当您尝试此操作时：

NSString * CatId = [[json objectAtIndex:i] objectForKey:@"id"];

它翻译成：数组->字典->字符串

但是你可以看到你不想要这个。
您需要：字典->数组->字典->字符串

代码：

NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
NSArray *array = [dict objectForKey:@"categories"];
NSString * CatId = [[array objectAtIndex:0] objectForKey:@"id"];

试试这个：

     NSURL * url = [NSURL URLWithString:@"http://myurl.json"];
     NSData * data = [NSData dataWithContentsOfURL:url];

    NSDictionary * json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
    NSArray *catsArray = [NSArray arrayWithArray:[json objectForKey:@"categories"]];

    cats = [[NSMutableArray alloc] init];

    for (int i = 0; i < catsArray.count; i++) {
        NSString * CatId = [[catsArray objectAtIndex:i] objectForKey:@"id"];
        NSString * CatName = [[catsArray objectAtIndex:i] objectForKey:@"name"];
        NSString * CatIcon = [[catsArray objectAtIndex:i] objectForKey:@"icon"];
        categories * cat = [[categories alloc] initWithCId:CatId andCName:CatName andCIcon:CatIcon];

        [cats addObject:cat];
    }

NSURL*url=[NSURL URLWithString:@”http://myurl.json"];
NSData*data=[NSData dataWithContentsOfURL:url]；
NSDictionary*json=[NSJSONSerialization JSONObject WithData:数据选项：kNilOptions错误：nil]；
NSArray*catsArray=[NSArray阵列WithArray:[json objectForKey:@“categories”]；
cats=[[NSMutableArray alloc]init]；
对于（int i=0；i

试试这个

NSURL * url = [NSURL URLWithString:@"http://myurl.json"];
NSData * data = [NSData dataWithContentsOfURL:url];

NSDictionary * json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];

NSArray * cat = [json objectForKey:@"categories"];

for(NSDictionary * tempdict in cat)
{
    NSString * CatId = [NSString stringWithFormat:@"%@",[tempdict objectForKey:@"id"]];
    NSString * CatName = [tempdict objectForKey:@"name"];
    NSString * CatIcon = [tempdict objectForKey:@"icon"];
    categories * cat = [[categories alloc] initWithCId:CatId andCName:CatName andCIcon:CatIcon];

}

---

此工作：将JSON视为NSMutabReLayle，然后很容易逐个获取对象数组：

 NSMutableArray  *userDetails = [NSJSONSerialization JSONObjectWithData:returnData options:0 error:nil];
    NSLog(@"User Det %@", userDetails);
    if (userDetails == nil || [userDetails count] == 0) {

    } else {

          // 3. iterate the array; each element is a dictionary...
          for (NSDictionary *lesson in userDetails)
          {

             NSString * CatId = [[catsArray objectAtIndex:i] objectForKey:@"id"];
             NSString * CatName = [[catsArray objectAtIndex:i] objectForKey:@"name"];
             NSString * CatIcon = [[catsArray objectAtIndex:i] objectForKey:@"icon"];
             categories * cat = [[categories alloc] initWithCId:CatId andCName:CatName andCIcon:CatIcon];
             [cats addObject:cat];
           }

}

---

当你使用上面的代码时，你得到了什么？一个空数组，对吗？

  NSURL * url = [NSURL URLWithString:@"http://myurl.json"];
    NSData * data = [NSData dataWithContentsOfURL:url];

    NSDictionary *jsonData = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];

    NSArray *myArray = [jsonData objectForKey:@"categories"];

    cats = [[NSMutableArray alloc] init];

    for (NSDictionary *temp in myArray) {

        NSString * CatId = [NSString stringWithFormat:@"%d",[temp objectForKey:@"id"]];
        NSString * CatName = [temp objectForKey:@"name"];
        NSString * CatIcon = [temp objectForKey:@"icon"];
        categories * cat = [[categories alloc] initWithCId:CatId andCName:CatName andCIcon:CatIcon];

        [cats addObject:cat];
   }