Delegate ARC

EmailShareType.m

#import "EmailShareType.h"

@implementation EmailShareType
{
    UIViewController *pvController;
}

- (void)share:(UIViewController *)parentViewController
{
    pvController = parentViewController;
    
    MFMailComposeViewController *mailComposeController = [[MFMailComposeViewController alloc] init];
    mailComposeController.mailComposeDelegate = self;
    [mailComposeController setSubject:@"Title"];
    [mailComposeController setMessageBody:@"Message" isHTML:YES];
    [parentViewController presentModalViewController:mailComposeController animated:YES];
}

- (void)mailComposeController:(MFMailComposeViewController *)controller didFinishWithResult:(MFMailComposeResult)result error:(NSError *)error
{
    [pvController dismissModalViewControllerAnimated:YES];
    
    if(self.completionHandler)
    {
        self.completionHandler();
    }
}
@end

ViewController.m

#import "ViewController.h"

#import "EmailShareType.h"

@interface ViewController ()

@end

@implementation ViewController

- (IBAction)emailAction:(id)sender
{
    __block EmailShareType *email = [[EmailShareType alloc] init];
    email.completionHandler = ^{
        NSLog(@"Done");
    };
    [email share:self];
}

@end