ios - MFMailComposeViewController 的委托(delegate)未处理 'Cancel' 按钮或 iOS 4.x 及更早版本

Question

我已经根据 Apple 提供的代码示例在我的应用程序中实现了标准邮件功能。我的代码如下

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

    [mailer setDelegate:self];

    [mailer setSubject:@"Een berichtje via de iPhone app"];         mailer.mailComposeDelegate = self;
    NSArray *toRecipients = [NSArray arrayWithObjects:@"studio@vrtfm.be", nil];
    [mailer setToRecipients:toRecipients];

    NSString *emailBody = @"";
    [mailer setMessageBody:emailBody isHTML:NO];

    [self presentModalViewController:mailer animated:YES];
}
else
{
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Oeps..."
                                                    message:@"Dit toestel ondersteunt geen mail functionaliteit."
                                                   delegate:nil
                                          cancelButtonTitle:@"OK"
                                          otherButtonTitles:nil];
    [alert show];
}

- (void)mailComposeController:(MFMailComposeViewController*)controller didFinishWithResult:(MFMailComposeResult)result error:(NSError*)error 
{   
    switch (result)
    {
        case MFMailComposeResultCancelled:
            NSLog(@"Mail cancelled: you cancelled the operation and no email message was queued.");
            break;
        case MFMailComposeResultSaved:
            NSLog(@"Mail saved: you saved the email message in the drafts folder.");
            break;
        case MFMailComposeResultSent:
            NSLog(@"Mail send: the email message is queued in the outbox. It is ready to send.");
            break;
        case MFMailComposeResultFailed:
            NSLog(@"Mail failed: the email message was not saved or queued, possibly due to an error.");
            break;
        default:
            NSLog(@"Mail not sent.");
            break;
    }
        [self becomeFirstResponder];
    // Remove the mail view
    [self dismissModalViewControllerAnimated:YES];
}

点击“发送”按钮调用委托(delegate)，一切正常。但是，点击“取消”按钮并不会调用委托(delegate)，它只会使 View 变暗；该应用程序卡在那里。

注意事项: 我没有在我的应用程序中显示 StatusBar。

我没有使用 xib，而是代码 [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

此邮件功能在 iOS5、iOS5.1 上运行良好。但仅在较低版本中面临此问题。

我也尝试过使用 [mailer setMailComposeDelegate:self];

我当前的 xib 类大小为 (280,480)。

我在包含内容大小 (1540,960) 的 ScrollView 的单个 View 中使用多个 View 。

使用方法显示 View [scrollView scrollRectToVisible:frame animated:YES];

Answer 1

试试看这个example

简答:

尝试更改代码行

[mailer setDelegate:self];

到

mailer.mailComposeDelegate = self;