iOS - Twitter连接问题：“操作无法完成。 （可可错误3840.）“

Question

I am creating an app displaying my twitter timeline. But I sometimes get the following error:

Error Domain=NSCocoaErrorDomain Code=3840 "The operation couldn’t be completed. (Cocoa error 3840.)" (JSON text did not start with array or object and option to allow fragments not set.) UserInfo=0x1fd807c0 {NSDebugDescription=JSON text did not start with array or object and option to allow fragments not set.}

I am using the following code to retrieve the timeline of twitter:

-(void) getTimeLine{

ACAccountStore *account=[[ACAccountStore alloc] init];
ACAccountType *accountType=[account accountTypeWithAccountTypeIdentifier:ACAccountTypeIdentifierTwitter];
[activityIndicatorLoadTweets setHidden:NO];
[activityIndicatorLoadTweets startAnimating];
[account requestAccessToAccountsWithType:accountType options:nil completion:^(BOOL granted, NSError *error)
{
    if (granted==YES) {
        NSArray *arrOfAccounts=[account accountsWithAccountType:accountType];
        if ([arrOfAccounts count]!=0)
        {
            ACAccount *twitterAccount=[arrOfAccounts lastObject];
            NSURL *requestURL=[NSURL URLWithString:@"http://api.twitter.com/1/statuses/home_timeline.json"];
            NSMutableDictionary *params=[[NSMutableDictionary alloc] init];
            [params setObject:@"20" forKey:@"count"];
            [params setObject:@"1" forKey:@"include_entities"];

            SLRequest *postRequest=[SLRequest requestForServiceType:SLServiceTypeTwitter requestMethod:SLRequestMethodGET URL:requestURL parameters:params];

            postRequest.account=twitterAccount;

            [postRequest performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error)
            {
                if (responseData==nil) {
                    NSLog(@"Could not connect. Try Again.");
                    [self showLabelAndStartTimer];
                    lblStatus.text=@"Could not connect at the moment. Please try Again.";
                    [activityIndicatorLoadTweets setHidden:YES];
                    [activityIndicatorLoadTweets stopAnimating];
                }
                else{
                    lblStatus.hidden=YES;
                    self.arrDataSource=[NSJSONSerialization JSONObjectWithData:responseData options:NSJSONReadingMutableLeaves error:&error];

                    if ([self.arrDataSource count]!=0)
                    {
                        dispatch_async(dispatch_get_main_queue(), ^
                        {
                            [self.tableTweetsView reloadData];
                            [activityIndicatorLoadTweets setHidden:YES];
                            [activityIndicatorLoadTweets stopAnimating];
                            //[self fetchBollyTweetsFrom:self.arrDataSource];
                        });
                    }
                }

            }];

        }
    }
    else{
        NSLog(@"Failure to access acount. Please check your internet connection.");
        [activityIndicatorLoadTweets setHidden:YES];
        [activityIndicatorLoadTweets stopAnimating];
    }


}];

}

Please note that the error description is from the line:

self.arrDataSource=[NSJSONSerialization JSONObjectWithData:responseData options:NSJSONReadingMutableLeaves error:&error];

The error is mostly self explanatory but If my JSON is wrong, why I am getting successful response half of the time? Comments and suggestions on the code are also welcome as I am newbie in iOS programming and using JSON. Thanks.

Answer 1

connections to api.twitter.com has been restricted to TLS/SSL connections only. If your application still uses HTTP plaintext connections you will need to update it to use HTTPS connections check this link : https://dev.twitter.com/discussions/24239

Answer 2

Add the below code to get the full JSON string and know the reason behind your error:

NSString* newStr = [[NSString alloc] initWithData:responseData 
                                         encoding:NSUTF8StringEncoding];
NSLog(@"%@", newStr);
self.arrDataSource=[NSJSONSerialization JSONObjectWithData:responseData options:NSJSONReadingMutableLeaves error:&error];

Hope it helps.

Answer 3

Your code is calling version 1 of the Twitter API which was officially retired on June 11, 2013 . You should be using v1.1 .