swift3 - Swift 3 - 生成的 QR 代码 UIImage 要附加到电子邮件，但出现错误 "found nil while unwrapping an Optional value"

Question

我的 QR 码生成器正在工作，它会将图像显示到我的 qrImageView UIImageView。

现在，我想做的是将 QR 码图像附加到电子邮件中。尝试了下面指定的代码，但出现错误“展开可选值时发现 nil”。

请帮忙!

生成二维码的函数

  func generateQRCode(from string:String) -> UIImage? {

    let data =  string.data(using: String.Encoding.isoLatin1)

    if let filter = CIFilter(name:"CIQRCodeGenerator") {
        filter.setValue(data, forKey: "inputMessage")
        let transform = CGAffineTransform(scaleX: 100, y: 100)

        if let output = filter.outputImage?.applying(transform) {
            return UIImage(ciImage: output)
        }
    }
    return nil
}

@IBAction func generateAction(_ sender: Any) {

    if let actualText = qrCodeTextField.text {
        let image = generateQRCode(from: actualText)
        qrImageView.image = image
    }



}

将二维码附加到电子邮件的代码

func configureMailController() -> MFMailComposeViewController {
    let mailComposerVC = MFMailComposeViewController()

    mailComposerVC.mailComposeDelegate = self

    mailComposerVC.setToRecipients(["tsm@yahoo.com"])
    mailComposerVC.setSubject("\(subject) QR Code")
    mailComposerVC.setMessageBody("Please see attached QR Code", isHTML: false)

    //Add Image as Attachment

    if let image = qrImageView.image {
        let data: NSData = UIImagePNGRepresentation(image)! as NSData

        mailComposerVC.addAttachmentData(data as Data, mimeType: "image/png", fileName: "image")

    }


    return mailComposerVC

}

Answer 1

这对我有用。我必须先将 CIImage 转换为 UIImage，以便将 QRCode 附加到电子邮件中

func convert(cmage:CIImage) -> UIImage
{       
    let context:CIContext = CIContext.init(options: nil)
    let cgImage:CGImage = context.createCGImage(cmage, from: cmage.extent)!        
    let image:UIImage = UIImage.init(cgImage: cgImage)        
    return image
}

来源:Unable to convert CIImage to UIImage in Swift 3.0