Question

我知道之前曾有人问过这个问题，但对我没有任何帮助，我不得不再问一次。我想要一个图像作为导航栏中的后退按钮，只想更改后退按钮的外观。我不想添加按钮并为其添加选择器。

我尝试了以下代码：

let backImage = UIImage(named: "Back_button")

        let backAppearance = UIBarButtonItem.appearance()
        backAppearance.setBackButtonBackgroundImage(backImage, for: .normal, barMetrics: .default)

        navigationController?.navigationBar.backIndicatorTransitionMaskImage = backImage
        navigationItem.backBarButtonItem = UIBarButtonItem(title: "", style: UIBarButtonItem.Style.plain, target: nil, action: nil)

我还尝试使用情节提要设置背面图像和背面蒙版，但是这两种方法都在背面图像上放置了一个黑色圆圈。

我尝试通过使用代码将另一张图片的Alpha值设置为零来设置另一张图片作为后掩膜，但是它也不起作用。

请帮助。

Answer 1

我使用自定义UINavigationController进行此操作：

import Foundation
import UIKit

class NavigationViewController : UINavigationController
{
    override func viewDidLoad()
    {
        super.viewDidLoad()

        self.navigationBar.backIndicatorImage = UIImage(named: "Back_button")
        self.navigationBar.backIndicatorTransitionMaskImage = UIImage(named: "Back_button")

        self.navigationItem.backBarButtonItem = UIBarButtonItem(title: "", style: .plain, target: nil, action: nil)
    }
}

只需在界面构建器中更改UINavigationController的类。

Answer 2

let backButton = UIBarButtonItem()
backButton.title = "Back"
backButton.image = UIImage(named: "Back_button")
self.navigationController?.navigationBar.topItem?.backBarButtonItem = backButton

您可以执行此操作以自定义后退按钮。而且，您不必担心添加选择器。

Answer 3

只需在ViewController中添加以下方法：

func setLeftBarBackItem() {

    var leftBarBackItem = UIBarButtonItem()
    leftBarBackItem = UIBarButtonItem(image: #imageLiteral(resourceName: "imgBack"), style: .plain, target: self, action: #selector(self.clickToBtnBackItem(_:)))
    self.navigationItem.leftBarButtonItem = leftBarBackItem

}

func clickToBtnBackItem(_ sender: UIBarButtonItem) {
    view.endEditing(true)

    _ = navigationController?.popViewController(animated: true)

}

func setTranspertNavigation()
{    
    self.navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
    self.navigationController?.navigationBar.shadowImage = UIImage()
    self.navigationController?.navigationBar.isTranslucent = true
    self.navigationController?.view.backgroundColor = .clear
}

在ViewController的ViewDidLoad方法内部，将backButton设置为：

    self.navigationController?.isNavigationBarHidden = false
    AppDelegate.shared().setupNavigationBar()
    setLeftBarBackItem()
    setTranspertNavigation()
    self.title = "Title Here"

Answer 4

创建用于定义导航栏特征的自定义类
为UINavigationController创建扩展以对其进行配置


import UIKit

private final class MyNavigationBarTraits {

  public var backIndicatorImage: UIImage?
  public var backIndicatorTransitionMaskImage: UIImage?

  public func apply(to navigationBar: UINavigationBar) {
    navigationBar.backIndicatorImage = backIndicatorImage
    navigationBar.backIndicatorTransitionMaskImage = backIndicatorTransitionMaskImage
  }

  public init(navigationBar: UINavigationBar) {
    backIndicatorImage = navigationBar.backIndicatorImage
    backIndicatorTransitionMaskImage = navigationBar.backIndicatorTransitionMaskImage
  }
}

public typealias Callback<T> = (_: T) -> Void

public extension UINavigationController {

  private struct AssociationKeys {
    static var navigationBarTraits = "ws_nc_navigationBarTraits"
  }

  private var navigationBarTraits: MyNavigationBarTraits? {
    get {
      return objc_getAssociatedObject(self, &AssociationKeys.navigationBarTraits) as? MyNavigationBarTraits
    }
    set {
      objc_setAssociatedObject(self, &AssociationKeys.navigationBarTraits, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
    }
  }

  func configureBar(block: Callback<UINavigationBar>) {
    navigationBarTraits = MyNavigationBarTraits(navigationBar: navigationBar)
    block(navigationBar)
  }

  func resetBar() {
    navigationBarTraits?.apply(to: navigationBar)
    navigationBarTraits = .none
  }
}

然后您可以在ViewController的viewWillAppear（例如tintColor）中配置导航栏

  public override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    navigationController?.configureBar { navigationBar in
      // You can customize your navigation bar in here!
      navigationBar.tintColor = .red
    }
  }

如果只想在一个View Controller中使用此自定义设置，则应重置View Controller的viewWillDisappear

中的栏

  public override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)

    navigationController?.resetBar()
  }

iOS导航中的自定义后退按钮

4 个答案: