Post a Twitter status update without using any of the built-in UI on iOS. This uses the Twitter 1.1 API (not the deprecated REST APIs).

TwitterStatusUpdateWithoutUI.m

@import Accounts;
#import <Twitter/Twitter.h>

- (void)postTwitterStatusUpdate:(NSString *)statusMessage
{
    ACAccountStore *account = [ACAccountStore new];
    ACAccountType *accountType = [account accountTypeWithAccountTypeIdentifier:ACAccountTypeIdentifierTwitter];
    
    [account requestAccessToAccountsWithType:accountType options:nil completion:^(BOOL granted, NSError *error) {
        if (granted) {
            // Populate an array with all available Twitter accounts.
            NSArray *arrayOfAccounts = [account accountsWithAccountType:accountType];
            
            if ([arrayOfAccounts count] == 0) {
                // There are no Twitter accounts configured. Display an appropriate error message.
            } else {
                NSDictionary *message = @{@"status": statusMessage};
                NSURL *requestURL = [NSURL URLWithString:@"https://api.twitter.com/1.1/statuses/update.json"];
                SLRequest *postRequest = [SLRequest requestForServiceType:SLServiceTypeTwitter
                                                            requestMethod:SLRequestMethodPOST
                                                                      URL:requestURL
                                                               parameters:message];
                postRequest.account = [arrayOfAccounts firstObject];
                
                [postRequest performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error) {
                     if (error) {
                        // There was an error performing the request.
                        NSLog(@"%@", error.description);
                     }
                     else {
                        NSLog(@"Successfully posted status update!");
                     }
                }];
            }
        }
    }];
}