CODEWITHSUNDEEP
swiftvariablesfirebasefirebase-realtime-database
dwinnbrown
dwinnbrown

Reputation: 4009

Swift - Firebase snapshot into variable

So I am trying to change the contents of a variable with a snapshot that is being taken from my firebase database.

I have defined the variable and am then trying to use the setValue method to change the value of the locally stored variable to the value that is held on the database. However despite getting no errors, my function is not running as it should be - nothing is added to the database despite my variable apparently being '0'.

This is my code:

    var myVar = 1 as AnyObject

    currentUserHasVotedVar.observeSingleEventOfType(.Value, withBlock: { snapshot in
        myVar = snapshot.value
        print(myVar)
//should be set to '0' from db
        }, withCancelBlock: { error in
            print(error.description)
    })

    if myVar as! NSObject == 0 {
        print("Hasn't voted yet")
        pollRef.childByAppendingPath("leave").childByAutoId()
        myVar = 1
        print(myVar)
    }

Upvotes: 0

Views: 321

Answers (1)

Ymmanuel
Ymmanuel

Reputation: 2533

In this case "myVar" will always be 1, because the single event of type Value is asynchronous. so the order of execution is first:

var myVar = 1 as AnyObject

then..

if myVar as! NSObject == 0 {
 print("Hasn't voted yet")
 pollRef.childByAppendingPath("leave").childByAutoId()
 myVar = 1
 print(myVar)
}

(this code is never executed because myVar is always 1) and at last it executes the content of the callback...

{ snapshot in
  myVar = snapshot.value
  print(myVar)
}, withCancelBlock: { error in
  print(error.description)
}

In order to access the value of the firebase path in the "currentUserHasVotedVar" reference, you have to put your validation code inside the callback.

Upvotes: 1

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