我正在尝试创建一个使用Material Design库底部导航功能的iOS应用。我可以使用底部导航栏来编辑和显示视图控制器，但是我无法添加其他视图控制器并在单击不同选项卡时在它们之间切换。我将所有内容简化为两个文件：一个是我的入口视图控制器，底部导航的东西，另一个是一个死的简单视图控制器，我实例化3次用作三个标签的目标。
目前，我的具体错误是：
Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'headerViewController does not have a parentViewController. Use [self addChildViewController:appBar.headerViewController]. This warning only appears in DEBUG builds'
据我所知，这与我的标签视图有关。如果我注释掉self.viewControllers = [...]的行，那么它将加载得很好，但不能在视图控制器之间切换。
我并没有嫁给这种方法。如果还有另一种方法可以实现这一目标，我很乐意去了解它。我无法从文档中学到很多东西，但如果有其他类似标签的Material Design功能的文档可以大大相似，我认为这会指向正确的方向。这是我的入口视图控制器。我使用其中一个示例作为基础并对其进行了大量修改。
import Foundation
import MaterialComponents
import UIKit
class ICEBottomNavController: UITabBarController, MDCBottomNavigationBarDelegate
{
let appBar = MDCAppBar()
var colorScheme = MDCSemanticColorScheme()
// Create a bottom navigation bar to add to a view.
let bottomNavBar = MDCBottomNavigationBar()
init()
{
super.init(nibName: nil, bundle: nil)
initCommon()
}
@available(*, unavailable)
required init?(coder aDecoder: NSCoder)
{
super.init(coder: aDecoder)
initCommon()
}
func initCommon()
{
self.title = "Bottom Navigation (Swift)"
let statusVC = ICEChildBottomBarViewController( title: "Status", color: UIColor.orange )
let eventsVC = ICEChildBottomBarViewController( title: "Events", color: UIColor.blue )
let contactsVC = ICEChildBottomBarViewController( title: "Contacts", color: UIColor.cyan )
self.viewControllers = [ statusVC, eventsVC, contactsVC ]
self.addChildViewController( appBar.headerViewController )
let color = UIColor(white: 0.2, alpha:1)
appBar.headerViewController.headerView.backgroundColor = color
appBar.navigationBar.tintColor = .white
appBar.navigationBar.titleTextAttributes = [NSAttributedStringKey.foregroundColor : UIColor.white]
//appBar.headerViewController.viewControllers
commonBottomNavigationTypicalUseSwiftExampleInit()
}
func bottomNavigationBar(_ bottomNavigationBar: MDCBottomNavigationBar, didSelect item: UITabBarItem)
{
print( "did select item \(item.tag)" )
self.selectedIndex = item.tag
//self.viewControllers?[item.tag].addChildViewController( appBar.headerViewController )
//self.selectedViewController = self.viewControllers?[item.tag]
// self.viewControllers
}
func commonBottomNavigationTypicalUseSwiftExampleInit()
{
view.backgroundColor = .lightGray
view.addSubview(bottomNavBar)
// Always show bottom navigation bar item titles.
bottomNavBar.titleVisibility = .always
// Cluster and center the bottom navigation bar items.
bottomNavBar.alignment = .centered
// Add items to the bottom navigation bar.
let tabBarItem1 = UITabBarItem( title: "Status", image: nil, tag: 0 )
let tabBarItem2 = UITabBarItem( title: "Events", image: nil, tag: 1 )
let tabBarItem3 = UITabBarItem( title: "Contacts", image: nil, tag: 2 )
bottomNavBar.items = [ tabBarItem1, tabBarItem2, tabBarItem3 ]
// Select a bottom navigation bar item.
bottomNavBar.selectedItem = tabBarItem1;
bottomNavBar.delegate = self
}
func layoutBottomNavBar()
{
let size = bottomNavBar.sizeThatFits(view.bounds.size)
let bottomNavBarFrame = CGRect( x: 0,
y: view.bounds.height - size.height,
width: size.width,
height: size.height )
bottomNavBar.frame = bottomNavBarFrame
}
override func viewWillLayoutSubviews()
{
super.viewWillLayoutSubviews()
layoutBottomNavBar()
}
#if swift(>=3.2)
@available(iOS 11, *)
override func viewSafeAreaInsetsDidChange()
{
super.viewSafeAreaInsetsDidChange()
layoutBottomNavBar()
}
#endif
override func viewDidLoad()
{
super.viewDidLoad()
self.selectedIndex = 0
appBar.addSubviewsToParent()
// Theme the bottom navigation bar.
MDCBottomNavigationBarColorThemer.applySemanticColorScheme(colorScheme, toBottomNavigation: bottomNavBar);
}
override func viewWillAppear(_ animated: Bool)
{
super.viewWillAppear(animated)
self.navigationController?.setNavigationBarHidden( true, animated: animated )
}
}
// MARK: Catalog by convention
extension ICEBottomNavController
{
class func catalogBreadcrumbs() -> [String] {
return ["Bottom Navigation", "Bottom Navigation (Swift)"]
}
class func catalogIsPrimaryDemo() -> Bool {
return false
}
func catalogShouldHideNavigation() -> Bool {
return true
}
}
我的简单视图控制器应该由标签切换出来：
import Foundation
import MaterialComponents
import UIKit
class ICEChildBottomBarViewController: UIViewController
{
//let appBar = MDCAppBar()
//var colorScheme = MDCSemanticColorScheme()
var color: UIColor?
init( title: String, color: UIColor )
{
super.init(nibName: nil, bundle: nil)
self.title = title
self.color = color
}
@available(*, unavailable)
required init?(coder aDecoder: NSCoder)
{
super.init(coder: aDecoder)
}
override func viewDidLoad()
{
super.viewDidLoad()
view.backgroundColor = self.color
//appBar.addSubviewsToParent()
}
override func viewWillAppear(_ animated: Bool)
{
super.viewWillAppear(animated)
self.navigationController?.setNavigationBarHidden( true, animated: animated )
}
}
答案 0 :(得分：0)
只需在情节提要板上创建带有所需项目数量的常规导航栏即可。然后将其连接到这样的控制器。 （在这里，我在故事板中使用了3个项目的底部栏。）
//
// TabViewController.swift
// Test Navigation Bar
//
// Created by ido cohen on 25/11/2018.
// Copyright © 2018 IdoCohen. All rights reserved.
//
import UIKit
import MaterialComponents.MaterialBottomNavigation_ColorThemer
class TabViewController: UITabBarController, MDCBottomNavigationBarDelegate {
var colorScheme = MDCSemanticColorScheme()
let bottomNavBar = MDCBottomNavigationBar()
override func viewDidLoad() {
colorScheme.backgroundColor = .white
view.backgroundColor = colorScheme.backgroundColor
let tabBarItem1 = UITabBarItem(title: "Home", image: UIImage(named: "Home"), tag: 0)
let tabBarItem2 = UITabBarItem(title: "Messages", image: UIImage(named: "Email"), tag: 1)
let tabBarItem3 = UITabBarItem(title: "Favorites", image: UIImage(named: "Cake"), tag: 2)
tabBarItem3.selectedImage = UIImage(named: "Favorite")
bottomNavBar.items = [ tabBarItem1, tabBarItem2, tabBarItem3 ]
bottomNavBar.selectedItem = tabBarItem1
view.addSubview(bottomNavBar)
bottomNavBar.delegate = self
MDCBottomNavigationBarColorThemer.applySemanticColorScheme(colorScheme, toBottomNavigation: bottomNavBar)
}
func bottomNavigationBar(_ bottomNavigationBar: MDCBottomNavigationBar, didSelect item: UITabBarItem){
guard let fromView = selectedViewController?.view, let toView = customizableViewControllers?[item.tag].view else {
return
}
if fromView != toView {
UIView.transition(from: fromView, to: toView, duration: 0.3, options: [.transitionCrossDissolve], completion: nil)
}
self.selectedIndex = item.tag
}
func layoutBottomNavBar() {
let size = bottomNavBar.sizeThatFits(view.bounds.size)
let bottomNavBarFrame = CGRect(x: 0,
y: view.bounds.height - size.height,
width: size.width,
height: size.height)
bottomNavBar.frame = bottomNavBarFrame
}
override func viewWillLayoutSubviews() {
super.viewWillLayoutSubviews()
layoutBottomNavBar()
}
}
在本示例中，我还使用了一个过渡，以防您想拥有一个过渡。如果不是就删除它。
答案 1 :(得分：0)
您可以使用它来切换控制器的主要代码
class MaterialTabBarSimple: UITabBarController {
let bottomNavBar = MDCBottomNavigationBar()
// other code copy from Material doc
override func viewDidLoad() {
bottomNavBar = [ your tabBarItems ]
bottomNavBar.delegate = self
self.viewControllers = [ your controllers ]
}
}
extension MaterialTabBarSimple: MDCBottomNavigationBarDelegate {
func bottomNavigationBar(_ bottomNavigationBar: MDCBottomNavigationBar, didSelect item: UITabBarItem) {
print("did select item \(item.tag)")
self.selectedViewController = self.viewControllers![item.tag]
}
}
答案 2 :(得分：0)
此代码对我来说可以正常工作，因为它可以制作MDCBottomNavBar并在视图控制器之间进行切换。但是请确保您正在使用TabBarController。
import UIKit
import MaterialComponents
class TabBarController: UITabBarController, MDCBottomNavigationBarDelegate {
let bottomNavBar = MDCBottomNavigationBar()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func viewWillAppear(_ animated: Bool)
{
super.viewWillAppear(animated)
self.navigationController?.setNavigationBarHidden( true, animated: animated )
}
//Initialize Bottom Bar
init()
{
super.init(nibName: nil, bundle: nil)
commonBottomNavigationTypicalUseSwiftExampleInit()
}
@available(*, unavailable)
required init?(coder aDecoder: NSCoder)
{
super.init(coder: aDecoder)
commonBottomNavigationTypicalUseSwiftExampleInit()
}
// Bottom Bar Customization
func commonBottomNavigationTypicalUseSwiftExampleInit()
{
view.backgroundColor = .lightGray
view.addSubview(bottomNavBar)
// Always show bottom navigation bar item titles.
bottomNavBar.titleVisibility = .always
// Cluster and center the bottom navigation bar items.
bottomNavBar.alignment = .centered
// Add items to the bottom navigation bar.
let tabBarItem1 = UITabBarItem( title: "Status", image: nil, tag: 0 )
let tabBarItem2 = UITabBarItem( title: "Events", image: nil, tag: 1 )
let tabBarItem3 = UITabBarItem( title: "Contacts", image: nil, tag: 2 )
bottomNavBar.items = [ tabBarItem1, tabBarItem2, tabBarItem3 ]
// Select a bottom navigation bar item.
bottomNavBar.selectedItem = tabBarItem1;
bottomNavBar.delegate = self
}
func bottomNavigationBar(_ bottomNavigationBar: MDCBottomNavigationBar, didSelect item: UITabBarItem)
{
self.selectedIndex = item.tag
}
override func viewWillLayoutSubviews()
{
super.viewWillLayoutSubviews()
layoutBottomNavBar()
}
#if swift(>=3.2)
@available(iOS 11, *)
override func viewSafeAreaInsetsDidChange()
{
super.viewSafeAreaInsetsDidChange()
layoutBottomNavBar()
}
#endif
// Setting Bottom Bar
func layoutBottomNavBar()
{
let size = bottomNavBar.sizeThatFits(view.bounds.size)
let bottomNavBarFrame = CGRect( x: 0,
y: view.bounds.height - size.height,
width: size.width,
height: size.height )
bottomNavBar.frame = bottomNavBarFrame
}
}