Twitter.frameworkやSocial.frameworkのツイート画面でカーソルの初期位置を先頭にする

gistfile1.m

#import <Twitter/Twitter.h>
#import <Social/Social.h>

// TWTweetComposeViewControllerの場合 (for iOS5)
- (IBAction)tweet:(id)sender
{
    if ([TWTweetComposeViewController canSendTweet]) {
        // ツイート用の画面をを表示する
        TWTweetComposeViewController* composeViewController = [[TWTweetComposeViewController alloc] init];
        [composeViewController setInitialText:@"Hello World!"];
        [self presentViewController:composeViewController animated:YES completion:^{
            [self findTextViewAndMoveToTop:composeViewController.view];
        }];
    }
}

// SLComposeViewControllerの場合 (for iOS6)
- (IBAction)share:(id)sender
{
    if ([SLComposeViewController isAvailableForServiceType:SLServiceTypeTwitter]) {
        NSString *serviceType = SLServiceTypeTwitter;
        SLComposeViewController *composeViewController = [SLComposeViewController composeViewControllerForServiceType:serviceType];
        
        [composeViewController setInitialText:@"Hello World!"];
        [composeViewController setCompletionHandler:^(SLComposeViewControllerResult result) {
            if (result == SLComposeViewControllerResultDone) {
                NSLog(@"Done.");
            }
        }];
        [self presentViewController:composeViewController animated:YES completion:^{
            [self findTextViewAndMoveToTop:composeViewController.view];
        }];
    }
}

// TextViewが見つかればカーソル位置を先頭にする
- (void)findTextViewAndMoveToTop:(UIView *)view
{
    if ([view isKindOfClass:[UITextView class]]) {
        UITextView *textView = (UITextView *)view;
        textView.selectedRange = NSMakeRange(0, 0);
        return;
    }
    for (UIView *subview in [view subviews]) {
        [self findTextViewAndMoveToTop:subview];
    }
}

ARC環境の方はselfを__weakな変数に代入してから呼び出さないと循環参照になる可能性があるのでご注意下さい。