MFMailComposeViewController crashing while dismiss

问题:

I am using MFMailComposeViewController in my conde to provide Mail functionality but after sending mail or when i want to cancel mail it will be crashing.

below is my code:

(IBAction)FnForPlutoSupportEmailButtonPressed:(id)sender {
{
    if ([MFMailComposeViewController canSendMail])
    {
        MFMailComposeViewController *mailer = [[MFMailComposeViewController alloc] init];

        mailer.mailComposeDelegate = self;

        [mailer setSubject:@"Need help from Pluto support team"];

        NSArray *toRecipients = [NSArray arrayWithObjects:@"[e-mail]",nil];
        [mailer setToRecipients:toRecipients];


        NSString *emailBody = @"";

        [mailer setMessageBody:emailBody isHTML:NO];

        //mailer.modalPresentationStyle = UIModalPresentationPageSheet;

        [self presentModalViewController:mailer animated:YES];

    }
    else
    {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Failure"
                                                        message:@"Your device doesn't support the composer sheet"
                                                       delegate:nil
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles: nil];
        [alert show];
    }
} }

    (void)mailComposeController:(MFMailComposeViewController*)controller didFinishWithResult:(MFMailComposeResult)result error:(NSError*)error
{
// Notifies users about errors associated with the interface    
switch (result)
    {       case MFMailComposeResultCancelled:
                        break;
                    case MFMailComposeResultSaved:
                        break;
                    case MFMailComposeResultSent:
                        break;
                    case MFMailComposeResultFailed:
                        break;
                    default:
                        break;
    } 
    [self dismissModalViewControllerAnimated:YES];
     }

I have read all blog post but no solution is found, This blog post is having good explaination about this but as per this i am not presenting my view controller in viewdidload or viewdidappear.

I'm Getting EXE_BAD_ACCESS, Following is the crash log :

**

> #0  0x00000000 in ?? ()
> #1  0x01dc5aa4 in -[UIViewController _setViewAppearState:isAnimating:] ()
> #2  0x01dc5f47 in -[UIViewController __viewDidDisappear:] ()
> #3  0x01dc6039 in -[UIViewController _endAppearanceTransition:] ()
> #4  0x01dd2e7e in -[UIViewController(UIContainerViewControllerProtectedMethods) endAppearanceTransition] ()
> #5  0x01fc8de1 in -[UIWindowController transitionViewDidComplete:fromView:toView:] ()
> #6  0x01da334b in -[UITransitionView notifyDidCompleteTransition:] ()
> #7  0x01da3070 in -[UITransitionView _didCompleteTransition:] ()
> #8  0x01da531b in -[UITransitionView _transitionDidStop:finished:] ()
> #9  0x01d23fb6 in -[UIViewAnimationState sendDelegateAnimationDidStop:finished:] ()
> #10 0x01d24154 in -[UIViewAnimationState animationDidStop:finished:] ()
> #11 0x0163bbce in CA::Layer::run_animation_callbacks ()
> #12 0x03664fe4 in _dispatch_client_callout ()
> #13 0x03655997 in _dispatch_main_queue_callback_4CF ()
> #14 0x012c03b5 in __CFRunLoopRun ()
> #15 0x012bf804 in CFRunLoopRunSpecific ()
> #16 0x012bf6db in CFRunLoopRunInMode ()
> #17 0x030f1913 in GSEventRunModal ()
> #18 0x030f1798 in GSEventRun ()
> #19 0x01ce82c1 in UIApplicationMain ()

**

As per updated document of apple for ios 5 they mentioned :

presentModalViewController:animated:

Presents a modal view managed by the given view controller to the user. (Deprecated. Use presentViewController:animated:completion: instead.)

- (void)presentModalViewController:(UIViewController *)modalViewController animated:(BOOL)animated
Parameters

Dismisses the view controller that was presented by the receiver. (Deprecated. Use dismissViewControllerAnimated:completion: instead.)

- (void)dismissModalViewControllerAnimated:(BOOL)animated

I had tried this also but it still crashes

回答1:

You need to keep a strong reference to MFMailComposeViewController *mailer in your class, and after you dismiss it you can null that reference. Ask me how I know this :-)

@implememtation MyClass
{
    MFMailComposeViewController *mailer;
}
...

(IBAction)FnForPlutoSupportEmailButtonPressed:(id)sender {
{
    if ([MFMailComposeViewController canSendMail])
    {
        /* USE IVAR */mailer = [[MFMailComposeViewController alloc] init];

Later on, when completely done with it, you simply "mailer = nil;" to release it.

EDIT: What I do and suggest is to use a block to the main queue to do the release. If you just use 'self.mailer = nil' then the release happens after the final delegate method has finished and you are for sure no longer using it.

EDIT2: This crash does not happen all the time on all devices - I would say its somewhat of a race condition between when you receive the final delegate method and when its finished its work. Apple does not say anything about holding a reference one way or the other - however, general practice on Apple products is to assume any object you get is "on loan" through one runLoop, and thereafter if you want to keep a reference you have to retain the object.

回答2:

If your are having sharekit framework implemented in your code goto SHK.m and change

        [[currentView parentViewController] dismissModalViewControllerAnimated:YES];

to

        [currentView  dismissModalViewControllerAnimated:YES];

This will solve your problem.

Thanks everyone for response.

and also comment these lines

SHKSwizzle([MFMailComposeViewController class], @selector(viewDidDisappear:), @selector(SHKviewDidDisappear:));
if (NSClassFromString(@"MFMessageComposeViewController") != nil) SHKSwizzle([MFMessageComposeViewController class], @selector(viewDidDisappear:), @selector(SHKviewDidDisappear:));

回答3:

HI you can use following code to send mail mail app will not send any email form simulator you have to install you application on device. EXE_BAD_ACCESS comes when you try to access the object they are not in memory and remamber device is case sensitive.

-(void)sendMail:(id)sender
{
    //create instance of class at runtime.
    Class mailComposer = (NSClassFromString(@"MFMailComposeViewController"));
if (mailClass != nil)
{
        // check the current device is configured for sending emails
        //if it is not configured for mail you open mail application on device.
    if ([mailClass canSendMail])
    {
        [self displayComposerSheet];
    }
    else
    {
        [self launchMailAppOnDevice];
    }
}
else
{
    [self launchMailAppOnDevice];
}

}
-(void)displayComposerSheet 
 {
MFMailComposeViewController *mailPicker = [[MFMailComposeViewController alloc] init];
picker.mailComposeDelegate = self;

[picker setSubject:@"Welcome!"];

    //recipients

NSArray *to = [NSArray arrayWithObject:@"[e-mail]"];  

[picker setToRecipients:toRecipients];

    // Attach an image
NSString *filePath = [[NSBundle mainBundle] pathForResource:@"Default" ofType:@"png"];
NSData *imageData = [NSData dataWithContentsOfFile:filePath];
[picker addAttachmentData:myData mimeType:@"image/png" fileName:@"Default"];

    // Set email body text
    //NSString *emailBody = @"......!";
    //[picker setMessageBody:emailBody isHTML:NO];

[self presentModalViewController:picker animated:YES];
[picker release];
}


- (void)mailComposeController:(MFMailComposeViewController*)controller didFinishWithResult:   (MFMailComposeResult)result error:(NSError*)error 
{   
message.hidden = NO;
    // Notifies users about errors associated with the interface
switch (result)
{

    case MFMailComposeResultCancelled:
        message.text = @"Canceled";
        break;
    case MFMailComposeResultSaved:
        message.text = @"Saved";
        break;
    case MFMailComposeResultSent:
        message.text = @"Sent";
        break;
    case MFMailComposeResultFailed:
        message.text = @"Failed";
        break;
    default:
        message.text = @"Not sent";
        break;
}
[self dismissModalViewControllerAnimated:YES];
}

-(void)launchMailAppOnDevice
{
NSString *recipients = @"";
NSString *body = @"";

NSString *email1 = [NSString stringWithFormat:@"%@%@", recipients, body];
email1 = [email1 stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:email1]];
}

回答4:

Since the stop of the stack is 0x00000000, I'm assuming some code inside UIKit is jumping to a nil function pointer. Enable Zombies and see if you get a zombie object access error. (Edit your project scheme, under Run/Debug, Diagnostics tab, check "Enable Zombie Objects")

回答5:

try this code, this works well without crashing.. contact us method is button target selector..

    -(void)ContactUs:(UIButton*)button
    {
        Class mailClass = (NSClassFromString(@"MFMailComposeViewController"));
        if (mailClass != nil)
        {
            // We must always check whether the current device is configured for sending emails
            if ([mailClass canSendMail])
            {
                [self displayComposerSheet];
            }
            else
            {
                [self launchMailAppOnDevice];
            }
        }
        else
        {
            [self launchMailAppOnDevice];
        }

    }

-(void)displayComposerSheet 
{
    MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init];
    picker.mailComposeDelegate = self;

    //[picker setSubject:@"Hello from California!"];

    // Set up recipients

    NSArray *toRecipients = [NSArray arrayWithObject:@"[e-mail]"]; 
    //NSArray *ccRecipients = [NSArray arrayWithObjects:@"[e-mail]", @"[e-mail]", nil]; 
    //NSArray *bccRecipients = [NSArray arrayWithObject:@"[e-mail]"]; 

    [picker setToRecipients:toRecipients];
    //[picker setCcRecipients:ccRecipients];    
    //[picker setBccRecipients:bccRecipients];

    // Attach an image to the email
    /*NSString *path = [[NSBundle mainBundle] pathForResource:@"rainy" ofType:@"png"];
     NSData *myData = [NSData dataWithContentsOfFile:path];
     [picker addAttachmentData:myData mimeType:@"image/png" fileName:@"rainy"];*/

    // Fill out the email body text
    //NSString *emailBody = @"It is raining in sunny California!";
    //[picker setMessageBody:emailBody isHTML:NO];

    [self presentModalViewController:picker animated:YES];
    [picker release];
}
- (void)mailComposeController:(MFMailComposeViewController*)controller didFinishWithResult:(MFMailComposeResult)result error:(NSError*)error 
{   
    message.hidden = NO;
    // Notifies users about errors associated with the interface
    switch (result)
    {

        case MFMailComposeResultCancelled:
            message.text = @"Canceled";
            break;
        case MFMailComposeResultSaved:
            message.text = @"Saved";
            break;
        case MFMailComposeResultSent:
            message.text = @"Sent";
            break;
        case MFMailComposeResultFailed:
            message.text = @"Failed";
            break;
        default:
            message.text = @"Not sent";
            break;
    }
    [self dismissModalViewControllerAnimated:YES];
}

-(void)launchMailAppOnDevice
{
    NSString *recipients = @"";
    NSString *body = @"";

    NSString *email1 = [NSString stringWithFormat:@"%@%@", recipients, body];
    email1 = [email1 stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:email1]];
}

回答6:

If you are using ARC, the controller object will have been released before you call dismiss.

Retain the object somewhere besides a stack allocated variable.

回答7:

Have you set delegate MFMailComposeViewControllerDelegate in .h file. I have faced such problem in past. And error was very minor. Please check delegate in .h file.