Firebase Realtime Database Get Value and Increment - ios

Question

I have firebase realtime database. I have tags and users. When someone clicked the button i want to get like value from tag, increase it and update new value. But i have observer and i cant get updated value with this code:
DataService.dataService.TAG_REF.observe(.value, with: { (snapshot) in
self.tags = []
if let snapshots = snapshot.children.allObjects as? [FIRDataSnapshot] {
for snap in snapshots {
if let postDictionary = snap.value as? Dictionary<String, AnyObject> {
let key = snap.key
let tag = Tag(key: key, dictionary: postDictionary)
self.tags.insert(tag, at: 0)
}
}
}
self.dashCollectionView.reloadData()
}) { (error) in
print(error.localizedDescription)
}
And when i clicked button:
if sender.image(for: .normal) == UIImage(named: "like") {
DataService.dataService.TAG_REF.child(selectedTag.tagKey).observeSingleEvent(of: .value, with: { snapshot in
let totalLikeSnap = snapshot.value as! Dictionary<String, AnyObject>
var totalLike = totalLikeSnap["like"] as! Int
totalLike = totalLike + 1
DataService.dataService.TAG_REF.child(selectedTag.tagKey).child("like").setValue(totalLike)
})
let likedTags = DataService.dataService.CURRENT_USER_REF.child("likedTags").child(selectedTag.tagKey)
likedTags.setValue(["time": "getcurrenttimelater"])
sender.setImage(UIImage(named: "liked"), for: .normal)
sender.setTitle(String(selectedTag.tagLikes), for: .normal)
self.dashCollectionView.reloadData()
} else {
print("already liked")
}
But it is not increasing like. I will be happy if anyone help me to update data.
tags {
-bB1231e23a24 {
comment: 0
image: "1"
like: 1
}
}

Answer 1

First of all change the way you increment your like's in your Database.
func updateTotalNoOfPost(completionBlock : (() -> Void)){
let prntRef = FIRDatabase.database().reference().child("tags/\(selectedTag.tagKey)")
prntRef.child("like").runTransactionBlock({ (noOfLikes) -> FIRTransactionResult in
if let totalLikes = noOfLikes.value as? Int{
noOfLikes.value = totalLikes + 1
return FIRTransactionResult.successWithValue(noOfLikes)
}else{
return FIRTransactionResult.successWithValue(noOfLikes)
}
}, andCompletionBlock: {(error,completion,snap) in
print(error?.localizedDescription)
print(completion)
print(snap)
if !completion {
print("The value wasn't able to Update")
}else{
completionBlock()
}
})
}
There must be an array in which you must be saving your noOfLike's for your collectionView Datasource. When you update your Database, also update your collectionView Datasource.
When your user clicks the button, in your button Function :-
updateTotalNoOfLikes{
print("Value incremented!")
// Here add the value to your collectionView datasource
//And then call collectionView.reloadData()
}