为什么数组和字典的值在json解析中显示为null？

Question

hi i am new to iOS development. In above code i am calling a web service, which response is in json format. am want to do json parsing with response of that web service.

here, why value of json and registartion is showing null in console plz help me.

here is my WebSerVice.h file

@interface WebService : NSObject<NSURLConnectionDelegate ,NSURLConnectionDataDelegate> {
NSMutableData *data;
NSArray  * registrationDetail;
}
-(void)callWebService;
@end

here my web WebService.m file

@implementation WebService

-(void)callWebService {
NSString *JsonString =[ NSString stringWithFormat:@"http://bia.igreentechservices.com/ws/ws_registration.php?emailid=%@&password=%@&fname=%@&lname=%@&gender=%@&birthdate=%@&mobile=%@&address=%@&emergency_contact_no=%@&other_contact_no_1=%@&other_contact_no_2=%@",emailAdd,pwd,fName,lName,gen,bDate,mobileNum,add,emergencyContactNum,anotherContactNum1,anothercontactNum2]


   UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
   NSURL *url = [NSURL URLWithString:JsonString];
   NSURLRequest *request =[NSURLRequest  requestWithURL:url];
   NSURLConnection *myConnection =[[NSURLConnection alloc] initWithRequest:request delegate:self];
   [myConnection start];
}

-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {


 data= [[NSMutableData alloc] init];
}


-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)theData {
[data appendData:theData];
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection {
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
NSString *responseString = [[NSString alloc]
    initWithData:data encoding:NSUTF8StringEncoding];
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
registrationDetail = [json objectForKey:@"registration"];
NSLog(@"%@",json);
NSLog(@"%@",registrationDetail);
NSLog(@"%@",responseString);
NSLog(@"%@",data);

}

Answer 1

may be in your URL string inculding some whiteSpace you must add %20 in white-space. you just add bellow line of code :-

JsonString = [JsonString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

you also called you method using NSURLConnection like bellow:-

-(void)callWebService {
NSString *JsonString =[ NSString stringWithFormat:@"http://bia.igreentechservices.com/ws/ws_registration.php?emailid=%@&password=%@&fname=%@&lname=%@&gender=%@&birthdate=%@&mobile=%@&address=%@&emergency_contact_no=%@&other_contact_no_1=%@&other_contact_no_2=%@",emailAdd,pwd,fName,lName,gen,bDate,mobileNum,add,emergencyContactNum,anotherContactNum1,anothercontactNum2]


   UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
   NSURL *url = [NSURL URLWithString:JsonString];
   NSURLRequest *request =[NSURLRequest  requestWithURL:url];
   NSURLConnection *myConnection =[[NSURLConnection alloc] initWithRequest:request delegate:self];

    if(myConnection)
        {
            data=[[NSMutableData alloc]init]; 
        }
        else
        {
            NSLog(@"connection not complet")
        }

}


-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {

    [data setLength: 0];
}
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [data appendData:data];
}
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {

    NSLog(@"Error is %@",error);
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection {

    NSString *responseString = [[NSString alloc] initWithData:self.webData encoding:NSUTF8StringEncoding];

    data = nil;
    [connection release];
    [data release];

}