swift Firebase return in asynchron Task

Question

I have a problem with the Firebase SDK for iOS in swift 2. Im trying to set a picture to a downloaded from the Firebase storage. When I call the function it gives back nil. I th

Answer 1

Firebase is asynchronous as you mentioned so let it drive the flow of data within your app.

Don't try to return data from a Firebase block - let the block handle the returned data and then move to the next step once that data is valid within the block.

There's a couple of options:

One option is to populate your data from the .writeToFile completion handler

override func viewDidLoad() {
   super.viewDidLoad()
   downloadPic()
}

func downloadPic {
    let download = profilePicRef.writeToFile(localURL) { (URL, error) -> Void in
      if (error != nil) {
        // handle an error
      } else {
        imageView.image = UIImage(...
        //then update your tableview, start a segue, or whatever the next step is
      }
    }
}

A second option is add an observer to the node and when that completes, populate your imageView

override func viewDidLoad() {
   super.viewDidLoad()

   let download = storageRef.child('your_url').writeToFile(localFile)

   let observer = download.observeStatus(.Success) { (snapshot) -> Void in
     imageView.image = UIImage(...
     //then update your tableview, start a segue, or whatever the next step is
   }
}