cant able to show all firebase data to line chart - swift

Question

I am trying to show my firebase data into my line chart, but it only showing one data from database and I want to show all the data from database. I am just new at this so if anyone can help me with this it would be great.
let ref = Database.database().reference().child("WeightTracker")
ref.child("\(currentUser)").queryOrderedByKey().observeSingleEvent(of: .value) { (snapshot) in
for rest in snapshot.children.allObjects as! [DataSnapshot] {
guard let restDict = rest.value as? [String: Any] else { continue }
let weight = restDict["weight"] as? String
print(weight as Any)
let date = restDict["date"] as? String
print(date as Any)
var xAxisValues = [""]
var yAxisValues = [0.0]
let total = Int(Double(weight!)!) * Int(2.20)
xAxisValues.append(date!)
yAxisValues.append(Double(total))
let formatter = WTRandomVC(lineChart: self.lineChartsView, xArray: xAxisValues , yArray: yAxisValues)
self.lineChartsView?.data?.setValueFormatter(formatter)
continue
}
}

Answer 1

Your code loops over the results that you get from the database, and then creates a new formatter with that data for each individual item and sets it to the chart. That means that the chart will only show the last result from the database once the code is done. To show all results, you'll need to gather the data into a single formatter and then show that on the chat.
The code should look something like this:
let ref = Database.database().reference().child("WeightTracker")
ref.child("\(currentUser)").queryOrderedByKey().observeSingleEvent(of: .value) { (snapshot) in
var xAxisValues = [""]
var yAxisValues = [0.0]
for rest in snapshot.children.allObjects as! [DataSnapshot] {
guard let restDict = rest.value as? [String: Any] else { continue }
let weight = restDict["weight"] as? String
let date = restDict["date"] as? String
let total = Int(Double(weight!)!) * Int(2.20)
xAxisValues.append(date!)
yAxisValues.append(Double(total))
}
let formatter = WTRandomVC(lineChart: self.lineChartsView, xArray: xAxisValues , yArray: yAxisValues)
self.lineChartsView?.data?.setValueFormatter(formatter)
}
So in the above we've pulled the arrays with data, and the creation of a WTRandomVC, outside of the for loop, so that they only happen once for all of the data.