Question

我设置了一个iOS应用程序来下载和解析JSON Feed。它可以很好地获取数据，但我正在努力研究如何读取Feed的某些嵌套JSON数据。

以下是我尝试加载的JSON Feed： http://api.wunderground.com/api/595007cb79ada1b1/conditions/forecast/q/51.5171,0.1062.json

我要加载的JSON Feed部分是：

"forecast":{
    "txt_forecast": {
    "date":"1:00 AM BST",
    "forecastday": [
    {
    "period":0,
    "icon":"chancerain",
    "icon_url":"http://icons-ak.wxug.com/i/c/k/chancerain.gif",
    "title":"Thursday",
    "fcttext":"Clear with a chance of rain in the morning, then mostly cloudy with a chance of rain. High of 59F. Winds from the SSE at 5 to 10 mph. Chance of rain 60%.",
    "fcttext_metric":"Clear with a chance of rain in the morning, then mostly cloudy with a chance of rain. High of 15C. Winds from the SSE at 5 to 15 km/h. Chance of rain 60%.",
    "pop":"60"
    }

你看到有一个叫做“句号”：0和0期间有“icon”，“title”等......

我正在尝试访问该数据，但我不能。

以下是我访问嵌套JSON Feed的某个部分的代码：

NSError *myError = nil;
NSDictionary *res = [NSJSONSerialization JSONObjectWithData:responseData options:NSJSONReadingMutableLeaves  error:&myError];
NSArray *results = [res objectForKey:@"current_observation"];
NSArray *cur = [results valueForKey:@"weather"];
NSArray *windrep = [results valueForKey:@"wind_string"];
NSArray *UVrep = [results valueForKey:@"UV"];
NSArray *othertemprep = [results valueForKey:@"temperature_string"];
NSString *loc = [[results valueForKey:@"display_location"] valueForKey:@"city"];
NSString *countcode = [[results valueForKey:@"display_location"] valueForKey:@"country"];

如何更改以访问我想要的内容？

这是我的另一次尝试：

 NSString *test = [[[results valueForKey:@"forecast"] valueForKey:@"period:0"] valueForKey:@"title"];

感谢你的帮助，Dan。

Answer 1

period只是forecastday数组中包含的第一个字典中的一个键，值为0.它不会以任何方式识别字典。

要在forecastday的第一个元素中获取标题值，您的代码应如下所示：

NSString *title = results[@"forecast"][0][@"title"];

或者，如果您没有使用新的下标语法：

NSString *title = 
  [[[results objectForKey:@"forecast"] objectAtIndex:0] objectForKey:@"title"];

访问JSON Feed数据

1 个答案: