Question

我创建了一个导航栏，我试图在另一个视图控制器中调用。我通过调用我分成左，中，右按钮的方法来设置它。在我的另一个控制器中，我调用navbarcontroller并尝试调用我为其设置导航工具栏的方法。没有任何事情发生，但没有崩溃。

import UIKit

class NavBarController : UIViewController{

var screenSize: CGRect!

override func viewDidLoad() {
    super.viewDidLoad()

    setupNavigationBarItems()
    setupToolBarItems()

    self.navigationController?.isToolbarHidden = false
    self.view!.backgroundColor = .white

}

我导航栏的方法就是这个

func setupNavigationBarItems() {
    setupCenterNavButton()
    setupLeftNavButton()
    setupRightNavButton()
}
func showCalendarController() {
    let navController = CalendarController()
    self.present(navController, animated: true, completion: nil)
} //connect bottom bar buttons to controller
func showEventsController() {
    let navController = EventsController()
    self.present(navController, animated: true, completion: nil)
} //connect bottom bar buttons to controller

func setupNavigationBarItems() {
    setupCenterNavButton()
    setupLeftNavButton()
    setupRightNavButton()
} // top bar button setup

private func setupCenterNavButton() {
    let buttonFrame = UIView(frame: CGRect(x: 0, y: 0, width: 165, 
height: 20))
    mainFeedButton.frame = CGRect(x: 0,y: 0, width: 80,height: 20) as 
CGRect
    mainFeedButton.backgroundColor = UIColor.blue
    peekFeedButton.frame = CGRect(x: 85,y: 0, width: 80,height: 20) as 
CGRect
    peekFeedButton.backgroundColor = UIColor.blue
    buttonFrame.addSubview(mainFeedButton)
    buttonFrame.addSubview(peekFeedButton)
    navigationItem.titleView = buttonFrame
} //center bar buttons / action setup

private func setupLeftNavButton() {
    navigationItem.leftBarButtonItem = UIBarButtonItem(customView: 
favoriteButton)
}// left bar buttons / action setup

private func setupRightNavButton() {
    navigationItem.rightBarButtonItem = UIBarButtonItem(customView: 
moreButton)
} //right bar buttons / action setup

lazy var mainFeedButton: UIButton! = {
    let button = UIButton(type: .custom) // button type
    button.setTitle("Main",for: .normal) //button title
    button.sizeToFit()  // size button to fit the title
    var frame = button.frame //create frame to manipulate the body
    button.frame = CGRect(x: 0, y: 0, width: 100, height: 40)
    button.addTarget(self, action: 
#selector(self.showMainFeedController),
                     for: .touchUpInside)
    return button
}() //mainFeed button connected to Feed Controller

lazy var peekFeedButton: UIButton! = {
    let button = UIButton(type: .custom) //button type
    button.setTitle("Spy",for: .normal) //button title
    button.sizeToFit()  // size button to fit the title
    var frame = button.frame //create frame to manipulate the body
    button.frame = CGRect(x: 20, y: 0, width: 100, height: 40)
    button.addTarget(self, action: 
#selector(self.showSpyFeedController),
                     for: .touchUpInside)
    return button
}()//peekFeed button frame and action setup 

lazy var favoriteButton: UIButton! = {
    let button = UIButton(type: .system) //default button with blue 
text
    button.setImage(#imageLiteral(resourceName: 
"star").withRenderingMode(.alwaysOriginal), for: .normal)
    button.contentMode = .scaleAspectFit
    button.frame = CGRect(x: 0, y: 0, width: 24, height: 24)
    button.addTarget(self, action: #selector(favoriteButton_tapped),
                     for: .touchUpInside)
    return button
}() //favorites button frame and action setup

lazy var moreButton: UIButton! = {
    let button = UIButton(type: .system) //default button with blue 
text
    button.setImage(#imageLiteral(resourceName: 
"more").withRenderingMode(.alwaysOriginal), for: .normal)
    button.contentMode = .scaleAspectFit
    button.frame = CGRect(x: 0, y: 0, width: 24, height: 24)
    button.addTarget(self, action: #selector(moreButton_tapped),
                     for: .touchUpInside)
    return button
}() //more button frame and action setup

func showMainFeedController() {
    let navController = MainFeedController()
    self.present(navController, animated: true, completion: nil)
} //mainFeed button connected to Feed Controller
func showSpyFeedController() {
    let navController = SpyFeedController()
    self.present(navController, animated: true, completion: nil)
}//peekFeed button connected to SpyFeedController
func favoriteButton_tapped(sender: UIButton) {
    print("You touched this!")
}
func moreButton_tapped(sender: UIButton) {
    print("You touched this!")
}
}

然后尝试通过setupNavigationBarItems（）调用该函数，就像这样

import UIKit

class EventsController: UIViewController{

    override func viewDidLoad() {
        super.viewDidLoad()

        let navbar = NavBarController()
        navbar.setupNavigationBarItems()
        self.navigationController?.isToolbarHidden = false
        self.view.backgroundColor = .white

     }
}

我不确定这是否有效。我仍然对这一切都不熟悉。

Answer 1

目前尚不清楚你期望发生什么，但这是发生了什么：

    let navbar = NavBarController()

创建一个全新的NavBarController对象。

    navbar.setupNavigationBarItems()

调用NavBarController对象的setupNavigationBarItems。

    self.navigationController?.isToolbarHidden = false
    self.view.backgroundColor = .white

您的代码即将结束。 navbar是一个局部变量，因此NavBarController对象在一团烟雾中消失。结束。此对象已创建并配置为无用。

Answer 2

我记得我在2015年的iOS第一个月：D，对OOP没有任何了解，我也不知道如何将数据传递到另一个屏幕或类。

无论如何，您不要在NavBarController中创建EventsController课程的新实例。如果您想与NavBarController中的EventsController对话，那么您需要一个当前有效的参考。您也可以使用delegate（稍后搜索）。

因此，在您从EventsController展示或展示NavBarController之前，请将当前NavBarController个实例传递到下一个EventsController屏幕。但首先，你需要在EventsController中声明一个变量，对吗？：）

在NavBarController类中声明类型为EventsController的变量，如下所示：
```
var navBarController: NavBarController!
```
然后在你的这段代码中，在展示或展示之前将你的自我（NavBarController实例）传递给EventsController类，请注意你错误地给了一个错误的名字您的EventsController新实例，因此我将其重命名为：
```
func showEventsController() {
    let eventsController = EventsController()
    eventsController.navBarController = self // THIS :)
    self.present(eventsController, animated: true, completion: nil)
}
```

最后，而不是：

let navbar = NavBarController()
navbar.setupNavigationBarItems()

使用你声明的变量，如下所示：

self.navBarController.navbar.setupNavigationBarItems()

希望这有帮助！ :)

尝试以实用方式在另一个类中调用导航栏功能

2 个答案: