How to set backgroundColor of UISegmentedControl t

问题:

iOS 13 introduced some changes to the UISegmentedControl including a really nice animation when switching the selected segment. However I'm noticing that it's not displaying the backgroundColor property correctly, it always seems to have a bit of a tint to it.

I've seen questions that answer how to set the selectedSegmentTintColor and such but I'm struggling to set the backgroundColor to say .white, no matter what I do it always shows up a bit of a gray even though there's no tintColor or similar setting applied. Setting the backgroundColor to other colors shows the same behavior but its most obvious with white. Adding to the mystery is that while this difference shows up on both iOS 13 simulators and a physical device running iOS 13, the visual debugger (in XCode 11 GM2) does not show this difference!

Here's a couple screenshots showing that even though the backgroundColor of the UISegmentedControl is set to the same as the backgroundColor of the view shown behind it they are slightly different.

Device running iOS 13 (white backgroundColor)

Same view/code shown in Visual Debugger (white backgroundColor)

Device running iOS 13 (blue backgroundColor)

I've tried the suggestion of applying a backgroundImage as suggested in this SO post: UISegmentedControl iOS 13 clear color but that ends up reverting the style back to how it looked in iOS 12 and you lose the nice animation as well.

Any guidance or suggestions is greatly appreciated! I've also filed a bug report with Apple, will see if anything comes of that.

回答1:

I have the same issue and there is no cool way to resolve it. So I did this small workaround. I dont like it and I am not proud of it, but it works.

func fixBackgroundSegmentControl( _ segmentControl: UISegmentedControl){
    if #available(iOS 13.0, *) {
        //just to be sure it is full loaded
        DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) { 
            for i in 0...(segmentControl.numberOfSegments-1)  {
                let backgroundSegmentView = segmentControl.subviews[i]
                //it is not enogh changing the background color. It has some kind of shadow layer 
                backgroundSegmentView.isHidden = true 
            }
        }
    }
}

回答2:

SWIFT 3 & 4+

From this answer https://stackoverflow.com/a/31652184/3249196 , if you want an all white background without the grey overlay justr replace tintColor and backgroundColor with UIColor.white

extension UISegmentedControl {
    func removeBorders() {
        setBackgroundImage(imageWithColor(color: backgroundColor!), for: .normal, barMetrics: .default)
        setBackgroundImage(imageWithColor(color: tintColor!), for: .selected, barMetrics: .default)
        setDividerImage(imageWithColor(color: UIColor.clear), forLeftSegmentState: .normal, rightSegmentState: .normal, barMetrics: .default)
    }

    // create a 1x1 image with this color
    private func imageWithColor(color: UIColor) -> UIImage {
        let rect = CGRect(x: 0.0, y: 0.0, width:  1.0, height: 1.0)
        UIGraphicsBeginImageContext(rect.size)
        let context = UIGraphicsGetCurrentContext()
        context!.setFillColor(color.cgColor);
        context!.fill(rect);
        let image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        return image!
    }
}

回答3:

Works for me (Swift 5).

let background = myColors.background
let selectedColor = myColors.foreground

if #available(iOS 13.0, *)
{
    segmentedControl.tintColor = background
    segmentedControl.backgroundColor = background
    segmentedControl.selectedSegmentTintColor = selectedColor
    segmentedControl.setTitleTextAttributes([.foregroundColor: selectedColor as Any], for: .normal)
    segmentedControl.setTitleTextAttributes([.foregroundColor: background as Any], for: .selected)
}
else
{
    segmentedControl.tintColor = background
    segmentedControl.backgroundColor = selectedColor
    segmentedControl.layer.cornerRadius = 4
}

回答4:

In Xamarin.iOS this worked for me:

class MySegmentedControl : UISegmentedControl
{
    int insertedIndex = 0;

    public override void InsertSubview(UIView view, nint atIndex)
    {
        base.InsertSubview(view, atIndex);

        if (insertedIndex == 2 || insertedIndex == 3)
            view.Hidden = true;

        insertedIndex++;
    }
}