AFNetworking freezes other actions - iphone

Question

I am building a chat application which repeatedly calls a web service using AFNetworking. The chat screen constantly polls this service for new chat messages. Everything related to the service works fine, but the UI keeps freezing and none of the buttons are working.
Here is the code:
- (void)GetAllIncomingMessages
{
NSURL *url = [NSURL URLWithString:weatherUrl];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
AFJSONRequestOperation *operation =
[AFJSONRequestOperation JSONRequestOperationWithRequest: request
success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
[self ParseJson:(NSDictionary *)JSON];
[self GetAllIncomingMessages];
} failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON)
{
[self GetAllIncomingMessages];
UIAlertView *av = [[UIAlertView alloc] initWithTitle:#"Error "
message:[NSString stringWithFormat:#"%#",error]
delegate:nil
cancelButtonTitle:#"OK" otherButtonTitles:nil];
[av show];
}];
[operation setAuthenticationChallengeBlock:
^( NSURLConnection* connection, NSURLAuthenticationChallenge* challenge )
{
if( [[challenge protectionSpace] authenticationMethod] == NSURLAuthenticationMethodHTTPBasic )
{
if( [challenge previousFailureCount] > 0 )
{
// Avoid too many failed authentication attempts which could lock out the user
[[challenge sender] cancelAuthenticationChallenge:challenge];
}
else
{
[[challenge sender] useCredential:[NSURLCredential credentialWithUser:#"username" password:#"password" persistence:NSURLCredentialPersistenceForSession] forAuthenticationChallenge:challenge];
}
}
else
{
// Authenticate in other ways than NTLM if desired or cancel the auth like this:
[[challenge sender] cancelAuthenticationChallenge:challenge];
}
}];
[operation start];
}
I reload the table view each time, but the UI still freezes. I tried using a background thread and that didn't work either.

Answer 1

I know this is an old question but I just bumped into it. Just FYI AFNetworking use a dispatched async queue to perform the connection operation and give back to you a JSON format of the NSData retrieved (as you probably already know) in the main queue. So AFNetworking is definitely not the problem.
My suggestion is try to perform ParseJson: and GetAllIncomingMessages: in a separated thread or dispatch an async queue yourself and you'll see your UI no longer freezing.
Something like:
static dispatch_queue_t your_app_queue() {
static dispatch_once_t onceToken;
static dispatch_queue_t _myQueue;
dispatch_once(&onceToken, ^{
_myQueue = dispatch_queue_create("com.myapp.queue", DISPATCH_QUEUE_SERIAL);
});
return _myQueue;
}
AFJSONRequestOperation *operation =
[AFJSONRequestOperation JSONRequestOperationWithRequest: request
success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
__block myClass = self;
dispatch_async(your_app_queue(), ^{
[myClass ParseJson:(NSDictionary *)JSON];
[myClass GetAllIncomingMessages];
});
}
failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON){
__block myClass = self;
dispatch_async(your_app_queue(), ^{
[myClass GetAllIncomingMessages];
dispatch_async(dispatch_get_main_queue(), ^{
UIAlertView *av = [[UIAlertView alloc] initWithTitle:#"Error "
message:[NSString stringWithFormat:#"%#",error]
delegate:nil
cancelButtonTitle:#"OK" otherButtonTitles:nil];
[av show];
});
});
}];
Or:
AFJSONRequestOperation *operation =
[AFJSONRequestOperation JSONRequestOperationWithRequest: nil
success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
[self performSelectorInBackground:#selector(ParseJson:) withObject:JSON];
[self performSelectorInBackground:#selector(GetAllIncomingMessages) withObject:nil];
}
failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON){
[self performSelectorInBackground:#selector(GetAllIncomingMessages) withObject:nil];
UIAlertView *av = [[UIAlertView alloc] initWithTitle:#"Error "
message:[NSString stringWithFormat:#"%#",error]
delegate:nil
cancelButtonTitle:#"OK" otherButtonTitles:nil];
[av show];
}];
And should be fine. Hope this help!