why doesn't my UIImage appear in my tabBar? - swift

Question

I'm trying to add an UIImage to customise my tabBar just like I did with my navigationBar, but it seems not work.
First I create a CAGradientLayer and then I turn it into UIImage. Here is the code:
extension CALayer {
func createImageFromLayer() -> UIImage?{
frame = CGRect(x: 0, y: 0, width: 1000, height: 1000)
UIGraphicsBeginImageContext(frame.size)
guard let context = UIGraphicsGetCurrentContext() else {return nil}
render(in: context)
let output = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return output
}
}
class CustomTabBarController: UITabBarController {
let grad: CAGradientLayer = {
let gradient = CAGradientLayer()
gradient.colors = [UIColor.clear, UIColor.black]
gradient.locations = [0,1]
return gradient
}()
override func viewDidLoad() {
super.viewDidLoad()
let tabImage = grad.createImageFromLayer()
self.tabBar.isTranslucent = true
self.tabBar.backgroundImage = tabImage
self.tabBar.shadowImage = UIImage()
}
}
Setting an image for my navigationBar worked perfectly using this method:
navigationController?.navigationBar.setBackgroundImage(barImg, for: UIBarMetrics.default)
In this code barImg is UIImage created from a CAGradientLayer just like with tabBar. I've checked if tabImage is nil and it's not.
It seems like tabBar doesn't have a function like tabBar.setBackgroundImage like navigationBar. How do I go about doing this?
The only result I get is a completely clear background for my tabBar with no gradient added and I don't know what I'm missing here once tabBar.backgroundImage doesn't work.
Thank you for the answers.

Answer 1

At first, when you setup colors for a CAGradientLayer you should use CGColor objects only. So you need to change that line to
gradient.colors = [UIColor.clear.cgColor, UIColor.black.cgColor]
After that your tabImage won't be empty and become visible.
The last problem is that you always set your image size to 1000x1000 pixels. That's way too much. To fix that you can pass target frame size to createImageFromLayer as a parameter. Its signature will become something like this.
func createImageFromLayer(targetFrame: CGRect) -> UIImage?
In your case targetFrame is tabBar.bounds.