MessageComposeResultFailed在这种情况下，如果触发以下代码

Question

对于这些下面的代码，我不理解MessageComposeResultFailed的情况。 当这些情况发生时

- (void)messageComposeViewController:(MFMessageComposeViewController *)controller didFinishWithResult:(MessageComposeResult) result
{
    switch (result)
    {
        case MessageComposeResultCancelled:
            break;

        case MessageComposeResultFailed:
            {
                UIAlertView *warningAlert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"Failed to send SMS!" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
                [warningAlert show];
                break;
            }

        case MessageComposeResultSent:
            break;

        default:
            break;
    }

    [self dismissViewControllerAnimated:YES completion:nil];
}

Answer 1

当用户尝试保存或发送消息失败时，将触发MessageComposeResultFailed 。 您可以参考文档以获取更多详细信息。 https://developer.apple.com/library/prerelease/ios/documentation/MessageUI/Reference/MFMessageComposeViewController_class/index.html#//apple_ref/c/tdef/MessageComposeResult