How to update progressView when downloading something in realm - ios

Question

I am trying to figure out how to use a progressView to show the progress of a something being downloaded using Realm. Through reading it seems that a Float called progress needs to be found, but I don't know how to find that in Realm. I have looked at the following questions, but I don't think that they are too helpful in this situation:
Swift: Realm - Update UI (Progress) while adding Data to DB
iOS-Swift How to update progressView
This is what I have at the moment:
ViewController:
import UIKit
import Realm
import RealmSwift
class ViewController: UIViewController {
var data = "Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Nam liber te conscient to factor tum poen legum odioque civiuda."
var realm: Realm!
#IBOutlet weak var saveBtn: UIButton!
#IBOutlet weak var progressView: UIProgressView!
override func viewDidLoad() {
super.viewDidLoad()
print("Hello")
print(Realm.Configuration.defaultConfiguration.fileURL!)
realm = try! Realm()
}
#IBAction func saveBtnPressed(_ sender: Any) {
saveToRealm(id: 1, name: "One", data: data)
let progress: Float = 0
progressView.setProgress(progress, animated: true)
}
func saveToRealm(id: Int, name: String, data: String) {
let realmSave = RealmSave()
realmSave.id = id
realmSave.name = name
realmSave.data = data
try? realm!.write {
realm.add(realmSave, update: true)
}
}
}
If there is anything that I can help with, please ask. Thank you

Answer 1

First: defining a let constant with a value of 0 will always stay 0. You can't dynamically change that to reflect the state of your download.
As a Realm engineer pointed out in this post "Realm has no way to know the total amount of data."
Estimating the progress should be done in your code.
You could try something like this:
func estimateProgress() {
let dataString = "Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Nam liber te conscient to factor tum poen legum odioque civiuda."
let data = dataString.data(using: .utf8)
let count = Float((data?.count)!)
let percentage: Float = count / 100
var progress: Float = 0
if progress < count {
progress += percentage
} else {
progress = count
}
progressView.setProgress(progress, animated: true)
print(progress)
}
Please note that this solution is for updating the UI and letting the user know that the saving to Realm is in progress. Since it uses the amount of bytes in the data, the larger the data, the longer it will take for the progress bar to fill. So it is good for UI, but it is not the actual state of progress.
And if you feel the progress bar is filling to slow/fast you can always tweak the percentage.