Rowan Stanley Rowan Stanley - 6 months ago 40
iOS Question

Page View Navigation Bar Title

I am having this issue with my code, whereby I have a function for my PageViewController, where it displays the title of the view controller on the navigation bar based on the view that the user is looking at. However, when I run the app, it starts off with no title, and the function only implements once the user starts to scroll through the pages. I was wondering if there is anything that I can do to fix this ? The function that I have used includes a switch statement, which can be seen below and in the whole class' code below:

func pageViewController(pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
if (!completed) {
return
}

if let firstViewController = viewControllers?.first,
let arrayIndex = orderedViewControllers.indexOf(firstViewController) {
switch arrayIndex {
case 0:
self.navigationController!.navigationBar.topItem!.title = "Monday"
break

case 1:
self.navigationController!.navigationBar.topItem!.title = "Tuesday"
break

case 2:
self.navigationController!.navigationBar.topItem!.title = "Wednesday"
break

case 3:
self.navigationController!.navigationBar.topItem!.title = "Thursday"

case 4:
self.navigationController!.navigationBar.topItem!.title = "Friday"
break

case 5:
self.navigationController!.navigationBar.topItem!.title = "Saturday"
break

case 6:
self.navigationController!.navigationBar.topItem!.title = "Sunday"
break

default:
self.navigationController!.navigationBar.topItem!.title = "Timetable"


}
}
}


Code: (PageViewController.swift)

import UIKit
import ChameleonFramework

class PageViewController: UIPageViewController,UIPageViewControllerDelegate {

// created for use in the function which determines the title of the navigationBar
var arrayIndex: Int = 0
// reference for later function to determine title of navigationBar
var pageControl = UIPageControl.self

// NSUserDefaults
let defaults = NSUserDefaults.standardUserDefaults()

// set of viewControllers (based on their storyboard ID)

private(set) lazy var orderedViewControllers: [UIViewController] = {
return [self.newDayViewController("monday"),
self.newDayViewController("tuesday"),
self.newDayViewController("wednesday"),
self.newDayViewController("thursday"),
self.newDayViewController("friday"),
self.newDayViewController("saturday"),
self.newDayViewController("sunday")
]
}()


override func viewDidLoad() {
super.viewDidLoad()


self.setNeedsStatusBarAppearanceUpdate()
// setting the datasource & Delegate of the UIPageViewController
dataSource = self
delegate = self



// set the first viewController for the pageView (monday as it is the first in the set)

if let firstViewController = orderedViewControllers.first {
setViewControllers([firstViewController],
direction: .Forward,
animated: true,
completion: nil)


}

}





// function to add view controllers
// function will only instantiateViewControllers which have a storyboard id containing 'day' e.g Monday, Tuesday, Wednesday

private func newDayViewController(day: String) -> UIViewController {
return UIStoryboard(name: "Main", bundle: nil) .
instantiateViewControllerWithIdentifier("\(day)")
}




// set the navigationBar title to the dayViewController's title
// if the user is looking at orderedViewControllers[1], then the title of that day is "Tuesday"

func pageViewController(pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
if (!completed) {
return
}

if let firstViewController = viewControllers?.first,
let arrayIndex = orderedViewControllers.indexOf(firstViewController) {
switch arrayIndex {
case 0:
self.navigationController!.navigationBar.topItem!.title = "Monday"
break

case 1:
self.navigationController!.navigationBar.topItem!.title = "Tuesday"
break

case 2:
self.navigationController!.navigationBar.topItem!.title = "Wednesday"
break

case 3:
self.navigationController!.navigationBar.topItem!.title = "Thursday"

case 4:
self.navigationController!.navigationBar.topItem!.title = "Friday"
break

case 5:
self.navigationController!.navigationBar.topItem!.title = "Saturday"
break

case 6:
self.navigationController!.navigationBar.topItem!.title = "Sunday"
break

default:
self.navigationController!.navigationBar.topItem!.title = "Timetable"


}
}
}
}
// Mandatory functions and setup for the pageViewController to work

extension PageViewController: UIPageViewControllerDataSource {


func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = orderedViewControllers.indexOf(viewController) else {
return nil
}
let previousIndex = viewControllerIndex - 1
guard previousIndex >= 0 else {
return orderedViewControllers.last
}
guard orderedViewControllers.count > previousIndex else {
return nil
}
return orderedViewControllers[previousIndex]
}

func pageViewController(pageViewController: UIPageViewController,
viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = orderedViewControllers.indexOf(viewController) else {
return nil
}
let nextIndex = viewControllerIndex + 1
let orderedViewControllersCount = orderedViewControllers.count


guard orderedViewControllersCount != nextIndex else {
return orderedViewControllers.first
}
guard orderedViewControllersCount > nextIndex else {
return nil
}
return orderedViewControllers[nextIndex]
}
// set number of viewControllers to be presented
func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int {
return orderedViewControllers.count
}
func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int {
guard let firstViewController = viewControllers?.first,
firstViewControllerIndex = orderedViewControllers.indexOf(firstViewController) else {
return 0
}
return firstViewControllerIndex
}
}

Answer

try self.navigationItem.title"or self.title

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