如何隐藏导航栏后退按钮中的后退箭头？

Question

I have a navigation controller for which I'd like to override the default back arrow image and text. Basically, instead of the < Back , I'd like to hide the little < arrow, and just show the Back text. I've been able to replace the back arrow with another image, so I figured i'd just try to replace it with an image and then set the image to match the color of the background. How can I accomplish this?

In AppDelegate.swift I have this:

extension UINavigationItem{
    override open func awakeFromNib() {
        super.awakeFromNib()
        let backItem = UIBarButtonItem()
        backItem.title = ""
        backItem.image = UIImage(named: "icons8_burger")
        self.backBarButtonItem = backItem
    }
}

In the viewDidLoad() for the controller that we are sent to when the button is clicked, I have this:

override func viewDidLoad() {
        super.viewDidLoad()
        let burger = UIImage(named: "icons8_burger")

        navigationController?.navigationBar.backIndicatorImage = burger
        navigationController?.navigationBar.backIndicatorTransitionMaskImage = burger
    }

So, any ideas how I can accomplish this? I haven't found what I'm looking for thus far.

Any advice appreciated!

Answer 1

If you do ,

navigationController?.navigationBar.backIndicatorImage = nil
navigationController?.navigationBar.backIndicatorTransitionMaskImage = nil

or

navigationController?.navigationBar.backIndicatorImage = UIImage(named: "")
navigationController?.navigationBar.backIndicatorTransitionMaskImage = UIImage(named: "")

Then by default iOS use < as default image.

To remove this image you need to add blank transparent image. I used sample from here and google image reference is here

Now reduce the image pixel size to (1,1) and add in your assets and use below code.

navigationController?.navigationBar.backIndicatorImage = UIImage(named: "Blank")
navigationController?.navigationBar.backIndicatorTransitionMaskImage = UIImage(named: "Blank")

Here Blank is the same image name in my asset.

Answer 2

Use an empty image object like below,

    let mask = UIImage()
    navigationController?.navigationBar.backIndicatorImage = mask
    navigationController?.navigationBar.backIndicatorTransitionMaskImage = mask
    self.navigationItem.backBarButtonItem = UIBarButtonItem(title: "Back", style: .plain, target: nil, action: nil)

Answer 3

If you want to use the appearance - both backIndicator* vars are read-only.
Try the next code-only approach. Tested on iOS 15.2

private func setupNavBar() {
    let navBarAppearance = UINavigationBarAppearance()
    let blankImage = UIImage.withColor(UIColor.white.withAlphaComponent(0))

    navBarAppearance.setBackIndicatorImage(blankImage, transitionMaskImage: blankImage)
}

extension UIImage {

    static func withColor(_ color: UIColor) -> UIImage {
        let onePx = pixelsToPoints(1)
        let rect = CGRect(x: 0, y: 0, width: onePx, height: onePx)

        UIGraphicsBeginImageContextWithOptions(rect.size, false, 0)
        let context = UIGraphicsGetCurrentContext()

        context!.setShouldAntialias(false)
        context!.setFillColor(color.cgColor)
        context!.fill(rect)

        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return image!
    }

    static func pixelsToPoints(_ pixels: CGFloat) -> CGFloat {
        return pixels / UIScreen.main.scale
    }
}

Answer 4

将emply图片应用于navigationController

navigationController?.navigationBar.backIndicatorImage = UIImage(named: "")