如何快速将图像从一个视图控制器传递到另一个视图控制器？

Question

My task in generating QRCode by sending some details to server, backend people will generate hashed id. By using this hashed id, I need to generate QRCode and pass it from one viewcontroller to another viewcontroller.

I am able to get QRCode image.But ,while parsing it to another view controller I am getting an error like

Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value

at the line productdetails.qrimgobj.image = imgobj.image . If anyone helps me to pass images would be great, and thank you in advance.

@IBAction func generateQRCode(_ sender: Any) {
        type = "0"
        getqrandimage()

    }

     func getqrandimage(){
        name = nametxt.text!
        phonenum = phonenumbertxt.text!
        landnum = landlinetxt.text!
        email = emailtxt.text!
        web = websitetxt.text!
        desc = descriptiontxt.text!
        price = pricetxt.text!
        offer = offers.text!


        let acce:String = UserDefaults.standard.string(forKey: "access-tokenn")!
        print(acce)

        let headers:HTTPHeaders = ["Authorization":"Bearer \(acce)"]
        parameter = ["type":type,"name":name,"plus_code":pluscode,"latitude":lat,"longitude":long,"location":address,"phone":phonenum,"isd_code":isd,"landline":landnum,"std_code":std,"email":email,"website":web,"description":desc,"price":price,"offer":offer]
        //  imgobj.image=UIImage(named: "Mahi.png")
        let imageobj = UIImage(named: "Mahi.png")!

        let ImageData = imageobj.jpegData(compressionQuality: 0.5)

        Alamofire.upload(multipartFormData: { (multipartFormData) in
            multipartFormData.append(ImageData!, withName: "photo", fileName: self.filename, mimeType: "image/jpeg")
            for (key, value) in self.parameter {
                multipartFormData.append(self.type.data(using: String.Encoding.utf8)!,withName: "type")
                multipartFormData.append(self.name.data(using: String.Encoding.utf8)!,withName: "name")
                multipartFormData.append(self.pluscode.data(using: String.Encoding.utf8)!,withName: "plus_code")
                multipartFormData.append(self.str1.data(using: String.Encoding.utf8)!,withName: "latitude")
                multipartFormData.append(self.str2.data(using: String.Encoding.utf8)!,withName: "longitude")
                multipartFormData.append(self.address.data(using: String.Encoding.utf8)!,withName: "location")
                multipartFormData.append(self.phonenum.data(using: String.Encoding.utf8)!,withName: "phone")
                multipartFormData.append(self.isd.data(using: String.Encoding.utf8)!,withName: "isd_code")
                multipartFormData.append(self.landnum.data(using: String.Encoding.utf8)!,withName: "landline")
                multipartFormData.append(self.std.data(using: String.Encoding.utf8)!,withName: "std_code")
                multipartFormData.append(self.email.data(using: String.Encoding.utf8)!,withName: "email")
                multipartFormData.append(self.web.data(using: String.Encoding.utf8)!,withName: "website")
                multipartFormData.append(self.desc.data(using: String.Encoding.utf8)!,withName: "description")
                multipartFormData.append(self.price.data(using: String.Encoding.utf8)!,withName: "price")
                multipartFormData.append(self.offer.data(using: String.Encoding.utf8)!,withName: "offer")
            }
        },to:Constants.productcreate,
          method: .post,
          headers: headers)
        { (result) in
            switch result {
            case .success(let upload, _, _):

                upload.uploadProgress(closure: { (Progress) in
                    print("Upload Progress: \(Progress.fractionCompleted)")
                })

                upload.responseJSON { response in
                    //self.delegate?.showSuccessAlert()
                    print(response.request)  // original URL request
                    print(response.response) // URL response
                    print(response.data)     // server data
                    print(response.result)   // result of response serialization
                    //                        self.showSuccesAlert()
                    //self.removeImage("frame", fileExtension: "txt")
                    if let JSON = response.result.value {
                      //  print("JSON: \(JSON)")
                        var responsedict:Dictionary = response.result.value as! [String:Any]
                        print(responsedict)
                        var subdic:[String:Any] = responsedict["data"] as! [String:Any]
                        print(subdic)
                        var dict:[String:Any] = subdic["product"] as! [String:Any]
                        print(dict)

                        self.qrid = dict["hashed_id"] as! String
                        print("qrcode\(self.qrid)")

                        self.qrgenerate()




                    }

                }


            case .failure(let encodingError):
                //self.delegate?.showFailAlert()
                print(encodingError)
            }

        }


    }
    func qrgenerate(){
        let data = qrid.data(using: .ascii, allowLossyConversion: false)
        let filter = CIFilter(name: "CIQRCodeGenerator")
        filter?.setValue(data, forKey: "InputMessage")
        let ciImage = filter?.outputImage
        let  transform = CGAffineTransform(scaleX: 10, y: 10)
        let transformimage = ciImage?.transformed(by: transform)
        qrim = UIImage(ciImage: transformimage!)
        imgobj.image=qrim

        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        let productdetails = storyboard.instantiateViewController(withIdentifier: "LocatemypicViewController") as! LocatemypicViewController
        print(imgobj.image)
        productdetails.qrimgobj.image = imgobj.image
        self.navigationController?.pushViewController(productdetails, animated: true)
    }

Answer 1

You're getting a crash here:

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let productdetails = storyboard.instantiateViewController(withIdentifier: "LocatemypicViewController") as! LocatemypicViewController
print(imgobj.image)
productdetails.qrimgobj.image = imgobj.image

Specifically in this line: productdetails.qrimgobj.image = imgobj.image ... This is because you are trying to access or rather passing an object ( UIImage ) to your qrimgobj which I presume is a UIImageView while that qrimgobj property is not yet initialized. One of the things you can do is to have a property that holds the image temporarily and then pass it to qrimgobj after the whole screen is loaded.

Example:

var qrimage: UIImage?

viewDidLoad() {
    super.viewDidLoad()
    self.qrimgobj.image = self.qrimage // Pass
}