【问题标题】：MFMailComposeViewController delegate not called未调用 MFMailComposeViewController 委托
【发布时间】：2015-08-14 07:46:28
【问题描述】：

即使我正在编写以下代码，我也无法调用 Mail composer 委托方法：

-(void)openMailComposerInViewController:(UIViewController *)hostController{
if ([MFMailComposeViewController canSendMail])
{
    // Email Subject
    NSString *emailTitle = @"Test Email";
    // Email Content
    NSString *messageBody = @"Test Email";
    // To address
    NSArray *toRecipents = [NSArray arrayWithObject:@"support@test.com"];

    mailComposer = [[MFMailComposeViewController alloc] init];
    mailComposer.mailComposeDelegate = self;
    [mailComposer setSubject:emailTitle];
    [mailComposer setMessageBody:messageBody isHTML:NO];
    [mailComposer setToRecipients:toRecipents];

    // Present mail view controller on screen

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

pragma mark - 邮件

- (void) mailComposeController:(MFMailComposeViewController *)controller    didFinishWithResult:(MFMailComposeResult)result error:(NSError *)error
{
  switch (result)
  {
    case MFMailComposeResultCancelled:
        NSLog(@"Mail cancelled");
        break;
    case MFMailComposeResultSaved:
        NSLog(@"Mail saved");
        break;
    case MFMailComposeResultSent:
        NSLog(@"Mail sent");
        break;
    case MFMailComposeResultFailed:
        NSLog(@"Mail sent failure: %@", [error localizedDescription]);
        break;
    default:
        break;
}

// Close the Mail Interface
[mailController dismissViewControllerAnimated:YES completion:NULL];
}

我不想给自己打电话

但是，我的代表没有被调用。请帮忙。单击“取消”或“发送邮件”按钮时应用程序崩溃

【问题讨论】：

你能提供你的崩溃日志吗？
为什么在提交邮件控制器后设置mailController = hostController？

标签： ios iphone mfmailcomposeviewcontroller

【解决方案1】：

我遇到了这个问题，我的问题是我有以下代码：

self.mailComposer.mailComposeDelegate = self
self.mailComposer = MFMailComposeViewController()

我在初始化 mailComposer 对象之前设置了委托。我只是将这两行切换到此，它起作用了：

 self.mailComposer = MFMailComposeViewController()
 self.mailComposer.mailComposeDelegate = self

【讨论】：

【解决方案2】：

由于 ARC，我丢失了编写委托的视图控制器，因此它没有被调用。下面的代码帮助我解决了这个问题：

+(MailComposer *)sharedInstance
{

  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    sharedMailComposer = [[MailComposer alloc]init];
  });
  return sharedMailComposer;

}

然后我在调用 MailComposerViewController 时使用了上面的实例

    [[MailComposer sharedInstance] openMailComposerInViewController:[(UINavigationController *)moduleRouter.container topViewController]];

成功了:)

【讨论】：

【解决方案3】：

setMailComposeDelegate 和 presentViewController 的类实例必须相同。

mailComposer.mailComposeDelegate = hostController;

[hostController presentViewController:mailComposer animated:YES completion:nil];

【讨论】：