HTTP Request with nested dictionary - iphone

Question

I need to access a web service with a POST method, with nested dictionary to receive relevant data. But I keep getting empty response. What am I doing wrong?
NSURL *url = [NSURL URLWithString:#"http://appzander.com/gateway.php"];
ASIFormDataRequest *_request = [ASIFormDataRequest requestWithURL:url];
__weak ASIFormDataRequest *request = _request;
AppDelegate *app = [[UIApplication sharedApplication] delegate];
NSDictionary *paramsDic = [[NSDictionary alloc] initWithObjectsAndKeys:
[NSNumber numberWithDouble:app.myLocation.longitude],#"longitude",
[NSNumber numberWithDouble:app.myLocation.latitude],#"latitude",
#"500000",#"radius",
#"1000",#"maxResults",
nil];
NSDictionary *requestDic = [[NSDictionary alloc] initWithObjectsAndKeys:
#"GetNearestStations",#"function",
#"false",#"debug",
paramsDic,#"params",
nil];
[request addRequestHeader:#"Content-Type" value:#"application/json"];
[request appendPostData:[[SBJsonWriter new] dataWithObject:requestDic]];
request.requestMethod = #"POST";
[request setDelegate:self];
[request setCompletionBlock:^{
NSData *responseString = [request responseData];// responseString];
NSLog(#"Response: %#", responseString);
[self plotCrimePositions:responseString];
}];
[request setFailedBlock:^{
NSError *error = [request error];
NSLog(#"Error: %#", error.localizedDescription);
}];
// 6
[request startAsynchronous];

Answer 1

Use ASIFormDataRequest
NSURL *url = [NSURL URLWithString:#"yourUrlhere"];
ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:url];
[request setRequestMethod:#"POST"];
[request setPostValue:email forKey:#"username"];
[request setPostValue:pasw forKey:#"pass"];
[request setDelegate:self];
[request startAsynchronous];

Answer 2

Solved- I wasn't sending the parameters properly:
NSURL *url = [NSURL URLWithString:#"http://appzander.com/gateway.php"];
ASIFormDataRequest *_request = [ASIFormDataRequest requestWithURL:url];
__weak ASIFormDataRequest *request = _request;
AppDelegate *app = (AppDelegate*)[[UIApplication sharedApplication] delegate];
NSDictionary *paramsDic = [[NSDictionary alloc] initWithObjectsAndKeys:
[NSNumber numberWithDouble:32.071738],#"longitude",
[NSNumber numberWithDouble:34.791295],#"langitude",
#"500000",#"radius",
#"1000",#"maxResults",
nil];
[request setPostValue:#"false" forKey:#"debug"];
[request setPostValue:#"GetNearestStations" forKey:#"function"];
SBJsonWriter *jsonWriter = [[SBJsonWriter alloc] init];
NSString *paramsDicJSON = [jsonWriter stringWithObject:paramsDic];
[request setPostValue:paramsDicJSON forKey:#"params"];
request.requestMethod = #"POST";
[request setDelegate:self];
[request setCompletionBlock:^{
NSString *responseString = [request responseString];
[self plotBikes:responseString];
}];
[request setFailedBlock:^{
NSError *error = [request error];
NSLog(#"Error: %#", error.localizedDescription);
}];
[request startAsynchronous];