GDirections Route on Map View Crash

Question

I am using AFNetworking, and I am following a tutorial about drawing routes on the iphone screen by getting directions from google directions. I am using JSON, and AFNetworking. I copied the code in from the tutorial you can find here: Tutorial

If you also choose to copy and test this code, just a note: You need the AFNetworking from this github page: AFNetworking Download

You also have to define the variable _path as an NSMutableArray in the .h yourself or you will get errors as they have not defined it but referenced it.

Here is the code:

        AFHTTPClient *_httpClient = [AFHTTPClient clientWithBaseURL:[NSURL URLWithString:@"http://maps.googleapis.com/"]];

    [_httpClient registerHTTPOperationClass: [AFJSONRequestOperation class]];

    NSMutableDictionary *parameters = [[NSMutableDictionary alloc] init];

    [parameters setObject:[NSString stringWithFormat:@"%f,%f", location.coordinate.latitude, location.coordinate.longitude] forKey:@"origin"];

    [parameters setObject:[NSString stringWithFormat:@"%f,%f", location2.coordinate.latitude, location2.coordinate.longitude] forKey:@"destination"];

    [parameters setObject:@"true" forKey:@"sensor"];

    NSMutableURLRequest *request = [_httpClient requestWithMethod:@"GET" path: @"maps/api/directions/json" parameters:parameters];

    request.cachePolicy = NSURLRequestReloadIgnoringLocalCacheData;

    AFHTTPRequestOperation *operation = [AFHTTPClient HTTPRequestOperationWithRequest:request success:^(AFHTTPRequestOperation *operation, id response) { 
        NSInteger statusCode = operation.response.statusCode;
        if (statusCode == 200) {
            [self parseResponse:response];

        } else {

        }
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) { }]; 

    [_httpClient enqueueHTTPRequestOperation:operation];

So heres my problem

Thank you to those who helped. I have tested out the code with no errors, but now found that while trying to make a route. It crashes here:

- (void)parseResponse:(NSDictionary *)response {

    NSArray *routes = [response objectForKey:@"routes"]; // CRASH HERE

    NSDictionary *routePath = [routes lastObject];

    if (routePath) {

        NSString *overviewPolyline = [[routePath objectForKey: @"overview_polyline"] objectForKey:@"points"];

        _path = [self decodePolyLine:overviewPolyline];

        NSInteger numberOfSteps = _path.count;

        CLLocationCoordinate2D coordinates[numberOfSteps];
        for (NSInteger index = 0; index < numberOfSteps; index++) {
            CLLocation *location = [_path objectAtIndex:index];
            CLLocationCoordinate2D coordinate = location.coordinate;

            coordinates[index] = coordinate;
        }

        MKPolyline *polyLine = [MKPolyline polylineWithCoordinates:coordinates count:numberOfSteps];
        [self.mapView addOverlay:polyLine];

        }

    }

With the error description:

-[__NSCFData objectForKey:]: unrecognized selector sent to instance 0x2004bb80

Can you guys help? Thanks!

Answer 1

Let me also say that the AFHTTPClient previously did not have this HTTPOperationWithRequest class method as shown, but I had to copy and paste it in from AFHTTPRequestOperation.

I cloned AFNetworking from your github link and found this in AFHTTPClient.h file:

- (AFHTTPRequestOperation *)HTTPRequestOperationWithRequest:(NSURLRequest *)request 
                                                    success:(void (^)(AFHTTPRequestOperation *operation, id responseObject))success
                                                    failure:(void (^)(AFHTTPRequestOperation *operation, NSError *error))failure;

I wonder why you are getting errors instead of "method not found" warning. HTTPRequestOperationWithRequest is instance method, not class method:

AFHTTPRequestOperation *operation = [_httpClient HTTPRequestOperationWithRequest:request success:^(AFHTTPRequestOperation *operation, id responseObject) {
        // do something
        ;
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        ;
    }];

By the way, tutorial you linked has it correctly.

Answer 2

Alright after playing a bit I figured it out. The route would only be an NSDictionary if JSONKit was included. Some relation with AFNetworking and JSONKit here. So, I already had the JSONKit files from before, because I knew about this. But AFHTTPClient was not accepting it, so I had to put the line:

        [_httpClient setDefaultHeader:@"Accept" value:@"application/json"];