为什么我的导航栏颜色在 Swift 中没有改变？答案

【问题标题】：Mhy my NavigationBar Colour is not changing in Swift?为什么我的导航栏颜色在 Swift 中没有改变？
【发布时间】：2021-07-14 13:17:23
【问题描述】：

我制作了一个自定义 NavigationBar 以在所有屏幕上使用，如下所示：

 import Foundation
 import UIKit

extension UIViewController {

func setUpNavigationBar() {

    self.navigationController?.navigationBar.backgroundColor = .yellow
    self.navigationController?.navigationBar.isTranslucent = false
    self.navigationController?.navigationBar.layer.masksToBounds = false
    
    let menuImageView = UIImageView.init(image: #imageLiteral(resourceName: "menu8"))
    menuImageView.tintColor = .darkGray
    menuImageView.frame = CGRect(x:0.0,y:0.0, width:25,height:25.0)
    menuImageView.contentMode = .scaleAspectFit
    menuImageView.widthAnchor.constraint(equalToConstant: 25).isActive = true
    menuImageView.heightAnchor.constraint(equalToConstant: 25).isActive = true
    menuImageView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(menuClick)))
    let btnMenu = UIBarButtonItem(customView: menuImageView)
    
    self.navigationItem.setLeftBarButton(btnMenu, animated: true)
}

@objc func menuClick(){
    SideMenuController.preferences.basic.menuWidth = self.view.frame.width*0.8
    if !(self.sideMenuController?.isMenuRevealed ?? false){
        self.sideMenuController?.revealMenu()
    }
  }    
}

然后像这样调用SignupVC ViewWillAppear：

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(true)
          setUpNavigationBar()
}

使用上面的代码，我没有得到黄色NavigationBar。我在 SignupVC 中得到NavigationBar，就像唯一的白色一样。没有leftbutton 的菜单。为什么？我哪里错了？

谢谢。

【问题讨论】：

您是否尝试过检查self.navigationController 是否为nil？
@EmilioPelaez 在哪里？我应该试试吗？以及如何？
这里 self.navigationController?.navigationBar.backgroundColor = .yellow 检查是否为 self. navigationcontroller 是否为 nil
@EmilioPelaez 我试过了.. 它不是零

标签： swift uinavigationbarappearance

【解决方案1】：

为了改变背景：

navigationController?.navigationBar.barTintColor = UIColor.yellow

100% 测试正常

这段代码：

func setUpNavigationBar() {

    navigationController?.navigationBar.barTintColor = UIColor.yellow
    self.navigationController?.navigationBar.isTranslucent = false
    self.navigationController?.navigationBar.layer.masksToBounds = false
    
    let menuImageView = UIImageView.init(image: UIImage.init(named: "day")!)
    menuImageView.tintColor = .darkGray
    menuImageView.frame = CGRect(x:0.0,y:0.0, width:25,height:25.0)
    menuImageView.contentMode = .scaleAspectFit
    menuImageView.widthAnchor.constraint(equalToConstant: 25).isActive = true
    menuImageView.heightAnchor.constraint(equalToConstant: 25).isActive = true
    menuImageView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(menuClick)))
    let btnMenu = UIBarButtonItem(customView: menuImageView)
    
    self.navigationItem.setLeftBarButton(btnMenu, animated: true)
}

【讨论】：