Swift2從Firebase中檢索圖片

Question

我試圖從Firebase中讀取/顯示圖片。我首先編碼圖像，然後將此編碼的字符串發佈到Firebase。這運行良好。當我嘗試解碼來自Firebase的編碼字符串並將其轉換爲圖像時，我得到一個零值異常。

這就是我現在的儲蓄圖像以火力

var base64String: NSString! 
func imagePickerController(picker: UIImagePickerController, didFinishPickingImage image: UIImage, editingInfo: [String : AnyObject]?) { 

    self.dismissViewControllerAnimated(true, completion: nil) 

    imageToPost.image = image 

    var uploadImage = image as! UIImage 
    var imageData = UIImagePNGRepresentation(uploadImage)! 
    self.base64String = imageData.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.Encoding64CharacterLineLength) 
    let ref = Firebase(url: "https://XXX.firebaseio.com") 

    var quoteString = ["string": self.base64String] 
    var usersRef = ref.childByAppendingPath("goalImages") 
    var users = ["image": quoteString] 
    usersRef.setValue(users) 

    displayAlert("Image Posted", message: "Your image has been successfully posted!") 
} 

這是我想讀從火力地堡

// ViewController.swift 

import UIKit 
import Firebase 

class ViewController: UIViewController { 
@IBOutlet weak var image: UIImageView! 
var base64String: NSString! 

@IBAction func buttonClicked(sender: AnyObject) { 

    sender.setTitle("\(sender.tag)", forState: UIControlState.Normal) 

} 

override func viewDidLoad() { 
    super.viewDidLoad() 
    // Do any additional setup after loading the view, typically from a nib. 

    let ref = Firebase(url: "https://XXX.firebaseio.com/goalImages/image/string") 

    ref.observeEventType(.Value, withBlock: { snapshot in 

     self.base64String = snapshot.value as! NSString 
     let decodedData = NSData(base64EncodedString: self.base64String as String, options: NSDataBase64DecodingOptions()) 
     //Next line is giving the error 
     var decodedImage = UIImage(data: decodedData!) 

     self.image.image = decodedImage 
     }, withCancelBlock: { error in 
      print(error.description) 
     }) 

} 

override func didReceiveMemoryWarning() { 
    super.didReceiveMemoryWarning() 
    // Dispose of any resources that can be recreated. 
} 
} 

錯誤的圖像說：「致命錯誤：意外發現零，同時展開一個可選值「; encodedData是零。有人可以解釋發生了什麼問題嗎？

Answer 1

而不是

let decodedData = NSData(base64EncodedString: self.base64String as String, 
            options: NSDataBase64DecodingOptions()) 

嘗試添加IgnoreUnknownCharacters

NSDataBase64DecodingOptions.IgnoreUnknownCharacters 

使用示例：編碼JPG，商店和火力

編碼讀取和寫入我們最喜歡的星船

if let image = NSImage(named:"Enterprise.jpeg") { 
    let imageData = image.TIFFRepresentation 
    let base64String = imageData!.base64EncodedStringWithOptions(.Encoding64CharacterLineLength) 
    let imageRef = myRootRef.childByAppendingPath("image_path") 
    imageRef.setValue(base64String) 

讀取和解碼

 imageRef.observeEventType(.Value, withBlock: { snapshot in 

      let base64EncodedString = snapshot.value 
      let imageData = NSData(base64EncodedString: base64EncodedString as! String, 
          options: NSDataBase64DecodingOptions.IgnoreUnknownCharacters) 
      let decodedImage = NSImage(data:imageData!) 
      self.myImageView.image = decodedImage 

      }, withCancelBlock: { error in 
       print(error.description) 
     }) 

Answer 2

火力地堡的工程師在這裏：

我強烈建議使用新的API Firebase Storage上傳圖像火力地堡。它使用簡單，成本低，並且由大規模的Google Cloud Storage支持。

您可以從NSData上傳或NSURL指向本地文件（我會告訴NSData，但原理是一樣的）：

// Data in memory 
let data: NSData = ... 

// Create a reference to the file you want to upload 
let riversRef = storageRef.child("images/rivers.jpg") 

// Upload the file to the path "images/rivers.jpg" 
let uploadTask = riversRef.putData(data, metadata: nil) { metadata, error in 
    if (error != nil) { 
    // Uh-oh, an error occurred! 
    } else { 
    // Metadata contains file metadata such as size, content-type, and download URL. 
    let downloadURL = metadata!.downloadURL 
    // This can be stored in the Firebase Realtime Database 
    // It can also be used by image loading libraries like SDWebImage 
    } 
} 

你甚至可以暫停和恢復上傳，你可以輕鬆地監控上傳進步：

// Upload data 
let uploadTask = storageRef.putData(...) 

// Add a progress observer to an upload task 
uploadTask.observeStatus(.Progress) { snapshot in 
    // Upload reported progress 
    if let progress = snapshot.progress { 
    let percentComplete = 100.0 * Double(progress.completedUnitCount)/Double(progress.totalUnitCount) 
    } 
}