MFMailComposer崩溃

Question

在我的应用中，我使用的是MFMailComposer。当我在没有邮件配置的情况下发送邮件(没有在设备上的邮件应用程序中输入邮件ID和密码)时，它会崩溃。

这是导致崩溃的代码行：

[self presentModalViewController:picker animated:YES];

Answer 1

-(void) showEmailModalView
{
    NSLog(@"Start method <ExportStatisticsController> : <showEmailModalView>  --");


    MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init];
    picker.mailComposeDelegate = self; // &lt;- very important step if you want feedbacks on what the 
    //user did with your email sheet

    [picker setSubject:SendEmailSubject];

    NSArray *torec=[[NSArray alloc] initWithObjects:SendEmailToEmailID, nil];
    [picker setToRecipients:torec];
    [torec release];

    //------ message body ---

    NSString *body =@"";
    body=[NSString stringWithFormat:@"%@ From : %@\n",body, emailTextField.text];
    body=[NSString stringWithFormat:@"%@ Subject : %@\n",body,subjectTextField.text];



    //email contents
    body = [NSString stringWithFormat:@"%@ Message : \n  %@", body,messageBodyTextView.text];


    [picker setMessageBody:body isHTML:NO]; // depends. Mostly YES, unless you want to send it as plain text (boring)

    picker.navigationBar.barStyle = UIBarStyleBlack; // choose your style, unfortunately, Translucent colors behave quirky.

    [self presentModalViewController:picker animated:YES];
    [picker release];
    NSLog(@"End method <ExportStatisticsController> : <showEmailModalView>  --");

}

// Dismisses the email composition interface when users tap Cancel or Send. Proceeds to update the message field with the result of the operation.

- (void)mailComposeController:(MFMailComposeViewController*)controller didFinishWithResult:(MFMailComposeResult)result error:(NSError*)error
{ 
    NSLog(@"Start method <ExportStatisticsController> : <didFinishWithResult>  --");
    // Notifies users about errors associated with the interface
    switch (result)
    {
        case MFMailComposeResultCancelled:
            NSLog(@"Message MFMailComposeResultCancelled");
            break;
        case MFMailComposeResultSaved:
            NSLog(@"Message MFMailComposeResultSaved");
            break;
        case MFMailComposeResultSent:
            NSLog(@"Message sent Successfuly");

            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Email" message:@"Mail Sent Successfully!"
                                                           delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil];
            [alert show];
            [alert release];

            break;
        case MFMailComposeResultFailed:
            NSLog(@"Message MFMailComposeResultFailed");
            break;

        default:
        {
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Email" message:@"Sending Failed - Unknown Error :-("
                                                           delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil];
            [alert show];
            [alert release];
        }

            break;
    }
    [self dismissModalViewControllerAnimated:YES];
    NSLog(@"End method <ExportStatisticsController> : <didFinishWithResult>  --");
}

Answer 2

你应该打电话给

[MFMailComposeViewController canSendMail]

在呈现视图控制器之前，例如

if ([MFMailComposeViewController canSendMail]) {
    MFMailComposeViewController *composer = [[MFMailComposeViewController alloc] init];
    [self presentModalViewController:composer];
} else {
    // Show error message maybe
}

Answer 3

那是真的。你必须配置你的邮件应用程序，并检查设备是否可以发送邮件。因为如果没有邮件应用程序，我们就可以通过模拟器发送邮件(我认为这是不可能的)。你的邮件的收件人必须知道他/她从哪里收到邮件，我认为发件人不能从代码中设置。我可能是错的，但这只是我的观点，因为我也在与同样的情况作斗争。

希望能有所帮助。