How do I get the progress bar to work in my iOS app? - ios

Question

I made a timer in Swift using the following code:
import UIKit
class ViewController: UIViewController {
// #IBOutlet var ProgressBar: UIProgressView!
#IBOutlet var label: UILabel!
var hours: Int = 0
var mins: Int = 0
var secs: Int = 0
override func viewDidLoad() {
super.viewDidLoad()
//ProgressBar.progress = 0.0
}
#IBAction func didTapAddButton() {
// var progress: Float = 0.0
//ProgressBar.progress = progress
let vc = storyboard?.instantiateViewController(identifier:"date_picker") as! DateViewController
vc.title = "New Event"
vc.completionHandler = { [weak self] name, date in
DispatchQueue.main.async {
self?.didCreateEvent(name: name, targetDate: date)
}
}
navigationController?.pushViewController(vc, animated: true)
}
private func didCreateEvent(name: String, targetDate: Date){
self.title = name
let difference = floor(targetDate.timeIntervalSince(Date()))
if difference > 0.0 {
let computedHours: Int = Int(difference) / 3600
let remainder: Int = Int(difference) - (computedHours * 3600)
let minutes: Int = remainder / 60
let seconds: Int = Int(difference) - (computedHours * 3600) - (minutes * 60)
print("\(computedHours) \(minutes) \(seconds)")
hours = computedHours
mins = minutes
secs = seconds
updateLabel()
startTimer()
}
else{
print("negative interval")
}
}
private func startTimer() {
Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true, block: { _ in
if self.secs > 0 {
self.secs = self.secs - 1
}
else if self.mins > 0 && self.secs == 0 {
self.mins = self.mins - 1
self.secs = 59
}
else if self.hours > 0 && self.mins == 0 && self.secs == 0 {
self.hours = self.hours - 1
self.mins = 59
self.secs = 59
}
self.updateLabel()
})
}
private func updateLabel() {
label.text = "\(hours):\(mins):\(secs)"
}
}
I am trying to make a progress bar somewhat show how much time is left. I want the bar to be full when there is no time left. How should I do this?
I tried searching how to do this but Google wasn't helpful.

Answer 1

So the first thing you want to do is bring all your values for hour, minutes, and seconds into a singular combined value, represented as something like totalSeconds or whatever you want.
var hours: Int = XXX
var minutes: Int = XXX
var seconds: Int = XXX
var totalSeconds: Int = 0
totalSeconds = getTotalSecondsFrom(hours, minutes, seconds)
func getTotalSecondsFrom(hours: Int, minutes: Int, seconds: Int) -> Int {
let hoursToSec = (hours * 60) * 60
let minutesToSec = minutes * 60
return hoursToSec + minutesToSec + seconds
}
Once you have all of your values brought down into a singular value now you have a representation for calculating a progress bar's maximum limit. Remember that a progress bar can only have values betweeen 0.0 and 1.0 which is perfect for a percentage calculation. In the interest of explaining in a way that will make sense for learning, let's look at this from a different perspective. How can we get a percentage from a total maximum, then map it to a value in the range of 0.0 -> 1.0?
func getCompletedPercent(currentSeconds: Int, totalSeconds: Int) -> Float {
return Float(currentSeconds) / Float(totalSeconds)
}
Why does this work? Well, let's assume our total seconds are 5000 and current is 500. Doing the math, 500 / 5000 = 0.1 which is 1/10th or 10% of 5000, which is exactly what we're looking for. With this knowledge in hand all you need to do at this point is set your progress bars maximum to 1.0 and then every second, in your timer, update it's current progress using the functional examples getTotalSecondsFrom(...) and getCompletedPercent(...). Of course your version may vary slightly, but the concepts are the same.