如何从NSData中获取细节

Question

我想从下面的URL获取指定的数据html_instructions。我可以从这个URL获取所有数据。

但是我只需要特定的html_instructions。如何分割数据?

我使用以下代码将URL转换为NSData:

 NSString *url = [NSString      stringWithFormat:@"http://maps.googleapis.com/maps/api/directions/json?origin=Chennai&destination=Madurai&sensor=false"];
    NSURL *googleRequestURL=[NSURL URLWithString:url];
    dispatch_async(kBgQueue, ^{
    NSData* data = [NSData dataWithContentsOfURL: googleRequestURL];
    });

Answer 1

用它作为:

    NSData* data = [NSData dataWithContentsOfURL:googleRequestURL];
    if (data == nil) {
        return;
    }
    NSError* error;
    NSMutableDictionary* json = [NSJSONSerialization
                                 JSONObjectWithData:data
                                 options:kNilOptions
                                 error:&error];
    NSLog(@"Json : %@",json);

希望对你有帮助。

Answer 2

我从下面的url中解析了json并打印了html指令尝试复制这段代码并尝试:http://maps.googleapis.com/maps/api/directions/json?origin=Toronto&目的地= Montreal&传感器= false

   NSData *receivedData = Received data from url;
   NSError* error;
   NSMutableDictionary* parsedJson = [NSJSONSerialization JSONObjectWithData:receiveData              options:kNilOptions  error:&error];
           NSArray *allkeys = [parsedJson allKeys];
        for(int i = 0; i < allkeys.count; i++){
            NSLog(@"############################");
            if([[allkeys objectAtIndex:i] isEqualToString:@"routes"]){
                NSArray *arr        = [responseJsonValue objectForKey:@"routes"];
                NSDictionary *dic   = [arr objectAtIndex:0];
                NSLog(@"ALL KEYS FROM ROUTE: %@", [dic allKeys]);
                NSArray *legs = [dic objectForKey:@"legs"];
                  NSLog(@"legs array count %d", legs.count);
                for(int i = 0;  i < legs.count; i++){
                    NSArray *stepsArr = [[legs objectAtIndex:i] objectForKey:@"steps"];
                    for (int i = 0; i < stepsArr.count; i++) {
                        NSLog(@"HTML INSTRUCTION %@", [[stepsArr objectAtIndex:i] objectForKey:@"html_instructions"]);
                    }
                }
            }
            NSLog(@"############################");
        }