Mail Compose Builder - Easy to use helper to present MailComposer, includes convenient category for UIViewController

MailComposerBuilder.h

//  Created by Andrew on 24.08.13.
//  Copyright (c) 2013 Andrew Tokarev. All rights reserved.
//
#import <Foundation/Foundation.h>
#import <MessageUI/MessageUI.h>

@interface MailComposerBuilder : NSObject<MFMailComposeViewControllerDelegate>

+ (id) builder;

- (id) withParentController:(UIViewController*)parentViewController;

- (id) withText:(NSString*)text;

- (id) withHtml:(NSString*)html;

- (id) withSubject:(NSString*)subject;

- (id) withToRecipient:(NSString*)recipient;

- (void) present;

@end


@interface UIViewController(MailComposerBuilder)

- (void) presentMailComposerWithRecipient:(NSString*)recipient subject:(NSString*)subject;

- (void) presentMailComposerWithSubject:(NSString*)subject text:(NSString*)text;

@end

MailComposerBuilder.m

//  Created by Andrew on 24.08.13.
//  Copyright (c) 2013 Andrew Tokarev. All rights reserved.
//
#import "MailComposerBuilder.h"

@interface MailComposerBuilder(/*Private*/)
@property (nonatomic, strong) UIViewController            * parentViewController;
@property (nonatomic, strong) MFMailComposeViewController *   mailViewController;

@property (nonatomic, strong) id this;
@end

@implementation MailComposerBuilder {
    
    MFMailComposeViewController * mailComposeViewController;
}

- (void) present
{
    if ([self isUnableToPresentMailComposer]) {
        [self showAlertAboutMailUnavaliability];
    }
    
    self.this = self;
    
    [self.parentViewController presentViewController:self.mailViewController
                                            animated:YES
                                          completion:NULL];
}

- (BOOL) isUnableToPresentMailComposer
{
    return !(self.parentViewController && self.mailViewController);
}

#pragma mark - MFMailComposeViewControllerDelegate

- (void)mailComposeController:(MFMailComposeViewController*)controller didFinishWithResult:(MFMailComposeResult)result error:(NSError*)error
{
	if (result == MFMailComposeResultFailed) {
        [self showAlertAboutMailSendingFailure];
	}
	
	[controller dismissViewControllerAnimated:YES completion:NULL];
    
    self.this = nil;
}

#pragma mark -

+ (id) builder
{
    return [self new];
}

- (id) withParentController:(UIViewController*)parentViewController
{
    self.parentViewController = parentViewController;
    
    return self;
}

- (id) withText:(NSString*)text
{
    [self.mailViewController setMessageBody:text isHTML:NO];
    
    return self;
}

- (id) withHtml:(NSString*)html
{
    [self.mailViewController setMessageBody:html isHTML:YES];
    
    return self;
}

- (id) withSubject:(NSString*)subject
{
    [self.mailViewController setSubject:subject];
    
    return self;
}


- (id) withToRecipient:(NSString*)recipient
{
    [self.mailViewController setToRecipients:@[recipient]];
    
    return self;
}

#pragma mark - 

- (MFMailComposeViewController *)mailViewController
{
    if (![MFMailComposeViewController canSendMail])
    {
        return nil;
    }
    
    if(!_mailViewController) {
        _mailViewController = [MFMailComposeViewController new];
        _mailViewController.mailComposeDelegate    = self; 
        _mailViewController.modalPresentationStyle = UIModalPresentationPageSheet;
    }
    
    return _mailViewController;
}

#pragma mark - Alerts

- (void)showAlertAboutMailUnavaliability
{
    [self showAlertWithMessage:NSLocalizedString(@"Mail is not configured on this device", @"MailComposer Mail Unavaliability Message")];
}

- (void)showAlertAboutMailSendingFailure
{
    [self showAlertWithMessage:NSLocalizedString(@"Mail was not sent", @"MailComposer Mail Failure Message")];
}

- (void)showAlertWithMessage:(NSString*)message
{
    [[[UIAlertView alloc]initWithTitle:NSLocalizedString(@"Mail", @"MailComposer Alert Title")
                               message:message
                              delegate:nil
                     cancelButtonTitle:@"OK" otherButtonTitles:nil]show];
}

@end


@implementation UIViewController(MailComposerBuilder)

- (void) presentMailComposerWithRecipient:(NSString*)recipient subject:(NSString*)subject
{
    [[[[[MailComposerBuilder builder] withParentController:self] withToRecipient:recipient] withSubject:subject] present];
}

- (void) presentMailComposerWithSubject:(NSString*)subject text:(NSString*)text;
{
    [[[[[MailComposerBuilder builder] withParentController:self] withSubject:subject] withText:text] present];
}

@end