ios - 按需重新加载 UITabBarController

Question

我有以下带有 2 个项目的 TabBarController。它显示正确。

我正在调用setupItems()当something时从另一个 Controller 运行改变它的值。

函数调用正确，问题是navFirstController.tabBarItem.image没有更新。

class TabBarController: UITabBarController {

  override func viewDidLoad() {
    super.viewDidLoad()
    setupItems()
  }

  func setupItems() {
    let scale: CGFloat = 0.35
    let navFirstController = UINavigationController(rootViewController: FirstController())

    let navSecondController = UINavigationController(rootViewController: SecondController())
    navSecondController.tabBarItem.image = UIImage.scale(image: UIImage(named: "image2")!, by: scale)
    navSecondController.tabBarItem.imageInsets = UIEdgeInsets(top: 8, left: 0, bottom: -8, right: 0)

    if something == true {
      navFirstController.tabBarItem.image = UIImage.scale(image: UIImage(named: "image1")!, by: scale)
    } else {
      navFirstController.tabBarItem.image = UIImage.scale(image: UIImage(named: "image3")!, by: scale)
    }

    navFirstController.tabBarItem.imageInsets = UIEdgeInsets(top: 8, left: 0, bottom: -8, right: 0)

    viewControllers = [navSecondController, navFirstController]
  }

}

我尝试过:

1) viewControllers?.remove(at: 1) setupItems()开头

2) navFirstController.removeFromParent() setupItems()开头

3) self.viewWillLayoutSubviews()在 setupItems() 末尾

4) self.view.setNeedsLayout() , self.view.setNeedsDisplay()在 setupItems() 末尾

Answer 1

我认为我们不需要再次创建 viewControllers 对象来更改选项卡栏图像。只是我们需要从 viewControllers 数组中获取 viewController 对象并更改图像。

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }
}

class SecondViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func btnClicked(_ sender: Any) {
        //change image of tab bar item on button clicked
        if let tabVC = self.tabBarController as? TabBarController {
            tabVC.changeImage()
        }
    }

}


class TabBarController: UITabBarController {

    override func viewDidLoad() {
        super.viewDidLoad()
        setupItems()
    }

    func setupItems() {
        let storyboard = UIStoryboard(name: "Main", bundle: Bundle.main)
        let firstVC = storyboard.instantiateViewController(withIdentifier: "First")
        let navFirstController = UINavigationController(rootViewController: firstVC)
        navFirstController.tabBarItem.image = UIImage(named: "Image1")

        let secondVC = storyboard.instantiateViewController(withIdentifier: "Second")
        let navSecondController = UINavigationController(rootViewController: secondVC)
        navSecondController.tabBarItem.image = UIImage(named: "Image2")

        viewControllers = [navSecondController, navFirstController]
    }

    func changeImage() {
        if let second = viewControllers?[1] as? UINavigationController {
            second.tabBarItem.selectedImage = UIImage(named: "Image3")
            second.tabBarItem.image = UIImage(named: "Image3")
        }
    }

}

注意如果您想更改选定的选项卡栏项目图像，请更改“selectedImage”值，否则更改“image”值。