如何为ios 8创建发送电子邮件？

Question

首先，我为ios 7创建发送电子邮件但是当运行ios 8时无法输入目标电子邮件地址和其他人，之后弹出电子邮件关闭.. 是否有特殊的流程为ios 8发送电子邮件？

// Open Email and add attachment
MFMailComposeViewController *mailController = [[MFMailComposeViewController alloc] init];
NSArray *recipients = @[@""];
mailController.mailComposeDelegate = self;
[mailController setToRecipients:recipients];
[mailController setSubject:@"File"];
NSData *attachment = [[NSData alloc] initWithContentsOfFile:xlsPath];
[mailController addAttachmentData:attachment   mimeType:@"application/vnd.ms-excel" fileName:@"Export.xls"];

mailController.navigationBar.tintColor = [UIColor whiteColor];
[self.navigationController presentViewController:mailController animated:YES completion:nil];