Programmatically setting progressTint on ProgressView changes progress bar size

Question

It's taken me days to track down where this issue is coming from.

I have a TableView with rows of custom Table Cells, inside each of which is a progress view. The app calls for the progress view tint to be green/amber/red based on how full it is.

I have discovered that setting the progressTint programmatically causes the progress bar to appear fuller than it should do.

Relevant code (tableView cellForRowAt):

    let Max:Double = MyGroup!.EndTimeSeconds - MyGroup!.StartTimeSeconds //10771
    let Progress:Double = Date().timeIntervalSince1970 - MyGroup!.StartTimeSeconds //1599.7007069587708       
    
    if (Max >= Progress) {
        Cell.DescriptionLabel.textColor = UIColor.black
        Cell.SubtitleLabel.textColor = UIColor.black
        Cell.TargetDeliveryTimeLabel.textColor = UIColor.pts_darkergrey
        Cell.ProgressView.setProgress(Float(Progress / Max), animated: false)
        Cell.ProgressView.progress = Float(Progress / Max)
        Cell.ProgressView.progressTintColor = UIColor.pts_green //if i comment these out it works.
        if (Max * 0.75 <= Progress) {
            Cell.ProgressView.progressTintColor = UIColor.pts_pbamber //if i comment these out it works.
        }
    } else {
        Cell.DescriptionLabel.textColor = UIColor.white
        Cell.SubtitleLabel.textColor = UIColor.white
        Cell.TargetDeliveryTimeLabel.textColor = UIColor.white
        Cell.ProgressView.setProgress(1, animated: false)
        Cell.ProgressView.progress = 1
        Cell.ProgressView.progressTintColor = UIColor.pts_pbred //if i comment these out it works.
    }
            
    Cell.ProgressView.layer.cornerRadius = 4
    Cell.ProgressView.clipsToBounds = true

Screenshot with progressTint calls commented out:

Screenshot with progressTint calls in effect:

Notice the second item's progress bar erroneously gets filled to almost 50% when the tint is set.

The progress bar should fill linearly over time - but this will stay stationary until the progress legitimately passes this point and then it continues like normal.

I may be seeing things but the problem seems to affect the top two items constantly, and not the rest (either as much, or not at all)

I have tried both ProgressView.progress and ProgressView.setProgress, and ProgressView.progressTintColor and PogressView.tintColor.

Answer 1

After some searching and testing... it would appear that the standard UIProgressView does not like some combination(s) of height, tint color and/or layer modified.

Try replacing your UIProgressView with this SimpleProgressView

It has defaults of:

• backgroundColor = white
• tintColor = blue
• cornerRadius = 4
• intrinsic height = 4

You should be able to use this as a direct replacement - no need to make any other changes to your existing code. It's @IBDesignable with cornerRadius and progress as @IBInspectable so you can set those and see the result in Storyboard.

@IBDesignable
class SimpleProgressView: UIView {
    
    @IBInspectable public var cornerRadius: CGFloat = 0 {
        didSet {
            progressBarView.layer.cornerRadius = cornerRadius
            layer.cornerRadius = cornerRadius
        }
    }
    
    private let progressBarView = UIView()
    private var widthConstraint: NSLayoutConstraint!

    // default height of
    override var intrinsicContentSize: CGSize {
        return CGSize(width: UIView.noIntrinsicMetric, height: 4.0)
    }
    
    // set the background color of the progressBarView to the tint color
    override var tintColor: UIColor! {
        didSet {
            progressBarView.backgroundColor = tintColor
        }
    }

    // update width constraint multiplier when progress changes
    @IBInspectable public var progress: Float = 0 {
        didSet {
            if let wc = widthConstraint {
                // cannot modify multiplier directly, so
                //  deactivate
                wc.isActive = false
                //  create new width constraint with percent as multiplier
                //  maximum of 1.0
                let pct = min(progress, 1.0)
                self.widthConstraint = progressBarView.widthAnchor.constraint(equalTo: widthAnchor, multiplier: CGFloat(pct))
                //  activate new width constraint
                self.widthConstraint.isActive = true
            }
        }
    }
    // we can set .progress property directly, or
    // call setProgress (with optional animated parameter)
    public func setProgress(_ p: Float, animated: Bool) -> Void {
        // don't allow animation if frame height is zero
        let doAnim = animated && progressBarView.frame.height != 0
        self.progress = p
        if doAnim {
            UIView.animate(withDuration: 0.3, animations: {
                self.layoutIfNeeded()
            })
        }
    }
    
    override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()
        if backgroundColor == nil {
            backgroundColor = UIColor.black.withAlphaComponent(0.1)
        }
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        commonInit()
    }
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        commonInit()
    }
    private func commonInit() -> Void {

        // default background color: black with 0.1 alpha
        if backgroundColor == nil {
            backgroundColor = UIColor.black.withAlphaComponent(0.1)
        }
        
        // default tint color
        tintColor = .blue

        // default corner radius
        cornerRadius = 4

        progressBarView.translatesAutoresizingMaskIntoConstraints = false
        addSubview(progressBarView)
        // create width constraint
        //  progressBarView width will be set to percentage of self's width
        widthConstraint = progressBarView.widthAnchor.constraint(equalTo: widthAnchor, multiplier: 0.0)
        NSLayoutConstraint.activate([
            // constrain progressBarView Top / Leading / Bottom to self
            progressBarView.topAnchor.constraint(equalTo: topAnchor),
            progressBarView.leadingAnchor.constraint(equalTo: leadingAnchor),
            progressBarView.bottomAnchor.constraint(equalTo: bottomAnchor),
            // activate width constraint
            widthConstraint,
        ])
        clipsToBounds = true
    }

}

Here's a quick test implementation, comparing UIProgressView on top and SimpleProgressView below. Progress bar will start at 10%, increment by 10% with each tap on the view, and change colors at 25, 75 and 100%:

class ViewController: UIViewController {

    let uiProgressView = UIProgressView()
    let simpleProgressView = SimpleProgressView()
    let labelA = UILabel()
    let labelB = UILabel()

    var curProgress: Float = 0
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
        
        labelA.text = "Default UIProgressView"
        labelB.text = "Custom SimpleProgressView"

        [labelA, uiProgressView, labelB, simpleProgressView].forEach { v in
            v.translatesAutoresizingMaskIntoConstraints = false
            view.addSubview(v)
        }
        
        let g = view.safeAreaLayoutGuide
        NSLayoutConstraint.activate([

            labelA.topAnchor.constraint(equalTo: g.topAnchor, constant: 100.0),
            labelA.leadingAnchor.constraint(equalTo: g.leadingAnchor, constant: 20.0),
            labelA.trailingAnchor.constraint(equalTo: g.trailingAnchor, constant: -20.0),

            uiProgressView.topAnchor.constraint(equalTo: labelA.bottomAnchor, constant: 12.0),
            uiProgressView.leadingAnchor.constraint(equalTo: g.leadingAnchor, constant: 20.0),
            uiProgressView.trailingAnchor.constraint(equalTo: g.trailingAnchor, constant: -20.0),
            uiProgressView.heightAnchor.constraint(equalToConstant: 80.0),

            labelB.topAnchor.constraint(equalTo: uiProgressView.bottomAnchor, constant: 40.0),
            labelB.leadingAnchor.constraint(equalTo: g.leadingAnchor, constant: 20.0),
            labelB.trailingAnchor.constraint(equalTo: g.trailingAnchor, constant: -20.0),
            
            simpleProgressView.topAnchor.constraint(equalTo: labelB.bottomAnchor, constant: 12.0),
            simpleProgressView.leadingAnchor.constraint(equalTo: g.leadingAnchor, constant: 20.0),
            simpleProgressView.trailingAnchor.constraint(equalTo: g.trailingAnchor, constant: -20.0),
            simpleProgressView.heightAnchor.constraint(equalToConstant: 80.0),
            
        ])
        
        let t = UITapGestureRecognizer(target: self, action: #selector(self.incProgress(_:)))
        view.addGestureRecognizer(t)
        
        // start at 10%
        incProgress(nil)
    }
    
    @objc func incProgress(_ g: UITapGestureRecognizer?) -> Void {
        // increment progress by 10% on each tap, up to 100%
        curProgress = min(1.0, curProgress + 0.10)

        uiProgressView.progress = curProgress
        simpleProgressView.progress = curProgress

        let formatter = NumberFormatter()
        formatter.numberStyle = .percent
        formatter.maximumFractionDigits = 2
        if let sPct = formatter.string(for: curProgress) {
            labelA.text = "Default UIProgressView: " + sPct
            labelB.text = "Custom SimpleProgressView: " + sPct
        }
        
        print(curProgress)

        if curProgress == 1.0 {
            uiProgressView.tintColor = .pts_red
            simpleProgressView.tintColor = .pts_red
        } else if curProgress >= 0.75 {
            uiProgressView.tintColor = .pts_amber
            simpleProgressView.tintColor = .pts_amber
        } else if curProgress >= 0.25 {
            uiProgressView.tintColor = .pts_green
            simpleProgressView.tintColor = .pts_green
        } else {
            uiProgressView.tintColor = .pts_blue
            simpleProgressView.tintColor = .pts_blue
        }

    }
}

I tried to match your custom colors:

extension UIColor {
    static let pts_green = UIColor(red: 0.35, green: 0.75, blue: 0.5, alpha: 1.0)
    static let pts_amber = UIColor(red: 0.95, green: 0.7, blue: 0.0, alpha: 1.0)
    static let pts_red = UIColor(red: 0.9, green: 0.35, blue: 0.35, alpha: 1.0)
    static let pts_blue = UIColor(red: 0.25, green: 0.75, blue: 1.0, alpha: 1.0)
    static let pts_darkergrey = UIColor(white: 0.2, alpha: 1.0)
}