这与之前已解决的问题有关（请参阅此处：Sharing variables）。如果你的变量仍未被识别，但是你传递变量的代码看起来很稳固，我什么都没看到。
在尝试将用户的电子邮件地址用作将图像上传到Firebase存储的文件路径的一部分时，我收到了未解决的标识符错误“电子邮件”。代码在这里：
import UIKit
import Firebase
import MobileCoreServices
import FirebaseStorage
class ThirdViewController: UIViewController {
@IBOutlet weak var uploadButton: UIButton!
@IBOutlet weak var progressView: UIProgressView!
override func viewDidLoad() {
super.viewDidLoad()
self.view.backgroundColor = UIColor(patternImage: UIImage(named:"Book Funnel")!)
// Do any additional setup after loading the view.
}
@IBAction func uploadButtonWasPressed(sender: AnyObject) {
let imagePicker = UIImagePickerController()
imagePicker.sourceType = .photoLibrary
imagePicker.mediaTypes = [kUTTypeImage as String, kUTTypeMovie as String]
imagePicker.delegate = self
self.present(imagePicker, animated: true, completion: nil)
}
func uploadImageToFirebaseStorage(data: NSData) {
let storageRef = FIRStorage.storage().reference(withPath: email/"/image.jpg")
let uploadMetadata = FIRStorageMetadata()
uploadMetadata.contentType = "image/jpeg"
let uploadTask = storageRef.put(data as Data, metadata: uploadMetadata) { (metadata, error) in
_ = metadata?.downloadURL
if (error != nil) {
print("I recieved an error! \(error?.localizedDescription)")
} else {
print ("Upload complete! Here's some metadata! \(metadata)")
}
let alert = UIAlertController(title: "Success!", message: "Image uploaded", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "okay", style: UIAlertActionStyle.default, handler: nil))
self.present(alert, animated: true, completion: nil)
}
uploadTask.observe(.progress) { [weak self] (snapshot) in
guard let strongSelf = self else { return }
guard let progress = snapshot.progress else { return }
strongSelf.progressView.progress = Float(progress.fractionCompleted)
}
}
var toPass: String!
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
/*
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
}
*/
}
extension ThirdViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
dismiss(animated: true, completion: nil)
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
guard let mediaType: String = info[UIImagePickerControllerMediaType] as? String else {
dismiss(animated: true, completion: nil)
return
}
if mediaType == (kUTTypeImage as String) {
if let originalImage = info[UIImagePickerControllerOriginalImage] as? UIImage, let imageData = UIImageJPEGRepresentation(originalImage, 0.8) {
uploadImageToFirebaseStorage(data: imageData as NSData)
}
} else {
print("Please select an image")
}
dismiss(animated: true, completion: nil)
func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {
if (segue.identifier == "segueTest") {
//Checking identifier is crucial as there might be multiple
// segues attached to same view
if let fourthVC = segue.destination as? FourthViewController {
fourthVC.toPass = "email"
}
}
}
}
}