I am failing to understand the fundamentals of what is needed to add my HomeViewController (UIViewController) as one of the tabs in my homeTabBarController (UITabBarController) using the setViewControllers method.
I have tried initializing this and simply adding it as a param in the method. There seems to be a difference between a view controller created via storyboard and one created programmatically because when I tried adding a viewcontroller:UIViewController programmatically to the setViewControllers method, it worked fine.
My code below compiles however I get a runtime exception Thread 1: EXC_BAD_ACCESS (code=2, address=0x7ff7b8491598) at the line when homeTabBarController.setViewControllers is called
`
func loadTabBar() {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let homeViewController = storyboard.instantiateViewController(identifier: Constants.Storyboard.homeViewController) as? HomeViewController
homeViewController!.title = "Home"
homeTabBarController.setViewControllers([homeViewController!], animated: false)
homeTabBarController.modalPresentationStyle = .fullScreen
present(homeTabBarController, animated: true)
}
`
//MARK: - Create the instances of ViewControllers
let grayViewController = HomeViewController()
let blueViewController = FirstViewController()
let brownViewController = SecondViewController()
override func viewDidLoad() {
super.viewDidLoad()
//set title of the viewcontrollers
grayViewController.title = "home"
blueViewController.title = "first"
brownViewController.title = "second"
//Assigne the viewcontrollers to the TabBarViewController
self.setViewControllers([ grayViewController, blueViewController, brownViewController], animated: false)
//set system images to each tabBars
guard let items = self.tabBar.items else {
return
}
let images = ["house.fill", "star.fill", "bell.fill"]
for i in 0...2 {
items[i].image = UIImage(systemName: images[i])
}
self.tabBar.tintColor = .black
}
// You can download the project from the below github link
https://github.com/ahmetbostanciklioglu/AddingTabBarControllerProgrammatically.git
Related
I have implemented a tabBar programmatically:
class ViewController: UIViewController {
let tabBarCnt = UITabBarController()
override func viewDidLoad() {
super.viewDidLoad()
tabBarCnt.tabBar.tintColor = UIColor.black
createTabBarController()
}
func createTabBarController() {
let firstVc = UIViewController()
let downloadViewController = DownloadsViewController()
downloadViewController.tabBarItem = UITabBarItem(tabBarSystemItem: .downloads, tag: 0)
let bookmarkViewController = BookmarksViewController()
bookmarkViewController.tabBarItem = UITabBarItem(tabBarSystemItem: .bookmarks, tag: 1)
let favoritesViewControllers = FavoritesViewController()
favoritesViewControllers.tabBarItem = UITabBarItem(tabBarSystemItem: .favorites, tag: 2)
// Adding navigationControllers
let controllerArray = [downloadViewController, bookmarkViewController, favoritesViewControllers]
// For somereason this made the word Home appear in first tab
tabBarCnt.viewControllers = controllerArray.map{ UINavigationController.init(rootViewController: $0)}
self.view.addSubview(tabBarCnt.view)
}
}
DownloadViewController.swift
class DownloadsViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = UIColor.green
self.title = "Downloads"
}
}
This is the result:
MY QUESTION IS:
Do I have to implement all the layouts of the different viewControllers downloadViewController, bookmarkViewController, favoritesViewControllers programmatically?
Can't I use the storyboard and associate a viewController and do all the UI design and implementation there like this:
The problem here is that if I will implement all the layout programmatically, it won't be an obvious or a practical thing to do.
And assigning DownloadsViewController to that storyboard ViewController, doesn't make it get display it when I navigate to DownloadsTab in the UITabBar.
Yes, you can do that currently your creating view controller instance programmatically, instead of that you have to load/get viewController instance from storyBoard like this.
UIStoryboard(name: "Main", bundle: Bundle.main).instantiateViewController(identifier: "downloadsVC") as! DownloadsViewController
before calling this method set viewController StoryboardID
There is such code, if user logged on - ViewController changes :
func ifLogged() {
let preferences = UserDefaults.standard
let token = "token"
if preferences.object(forKey: token) == nil {
// Doesn't exist and stop at the same viewController
} else {
let newViewController = GeneralChooser()
self.navigationController?.pushViewController(newViewController, animated: false)
// push new generalChooser when logged
}
}
But in this case I do not see view elements, just background color from ViewHelper class
class GeneralChooser: UIViewController{
override func viewDidLoad() {
super.viewDidLoad()
ViewHelper.BackGroundColor(view: self.view)
There is BackgroundColor func below
class func BackGroundColor(view: UIView){
let startColor = UIColor(red:0.15, green:0.50, blue:0.70, alpha:1.0)
let endColor = UIColor(red:0.58, green:0.65, blue:0.81, alpha:1.0)
let newLayer = CAGradientLayer()
newLayer.colors = [startColor.cgColor,endColor.cgColor]
newLayer.zPosition = -1
newLayer.frame = view.frame
view.layer.addSublayer(newLayer)
If i do not call this function in GeneralChooser class, the screen is black and there are not view elements, but in initial ViewController i see view elements, just background color is default.
What am I doing wrong. Thanks for all.
The problem is in this line
let newViewController = GeneralChooser()
this line doesn't load xib or reference the storyboard object associated with that class
Use instantiateViewController and give the viewController storyboard ID in storyboard say GeneralChooserView
let vc = self.storyboard?.instantiateViewController(withIdentifier:"GeneralChooserView")
self.navigationController?.pushViewController(vc!, animated: true)
Or if you are using xibs with GeneralChooser as xib file for GeneralChooser class
let vc = GeneralChooser(nibName: "GeneralChooser", bundle: nil)
self.navigationController?.pushViewController(vc, animated: true)
This seems to me like a basic question, but I have search for days and haven't been able to find an answer.
I have an empty View Controller in which I am trying to show a UIPageViewController populated with content from another VC. I have tried many ways of doing this but haven't been successful. I am following this tutorial: https://www.veasoftware.com/posts/uipageviewcontroller-in-swift-xcode-62-ios-82-tutorial, and I tried doing everything almost exactly the same as it explains. Can somebody point to what might be wrong?
By the way, my classes have their StoryboardID set correctly, and each VC is connected to its corresponding class.
Here is my Initial VC's code:
override func viewDidLoad() {
super.viewDidLoad()
pageViewController = self.storyboard?.instantiateViewController(withIdentifier: "PageViewController") as? UIPageViewController
pageViewController!.dataSource = self
let startVC = self.viewControllerAt(index: 0)
let viewControllers = NSArray(object: startVC)
pageViewController!.setViewControllers(viewControllers as! [ContentViewController], direction: .forward, animated: false, completion: nil)
self.pageViewController!.view.frame = self.view.bounds
addChildViewController(pageViewController!)
self.view.addSubview((pageViewController!.view)!)
pageViewController?.didMove(toParentViewController: self)
}
let cVC: ContentViewController = self.storyboard?.instantiateViewController(withIdentifier: "ContentViewController") as! ContentViewController
cVC.title = "Title \(index)"
cVC.nAuthor = "Author"
cVC.nCategory = "Sports"
cVC.nBody = "Lorem ipsum...."
cVC.pageIndex = index
return cVC
}
This is my content class:
override func viewDidLoad() {
super.viewDidLoad()
newsTitle.text = nTitle
newsAuthor.text = nAuthor
newsCategory.text = nCategory
newsBody.text = nBody
}
For future references to people with the same problem. After an arduous investigation, I saw than in swift (at least 3) I have to declare the storyboard before I call it! Might be an amateur mistake.
So before:
let cVC: ContentViewController = self.storyboard?.instantiateViewController(withIdentifier: "ContentViewController") as! ContentViewController
I had to include:
let storyboard = UIStoryboard(name: "Main", bundle: nil)
My goal is whenever i click a button on a first view controller, then it will navigate to another controller which is a navigation controller.
firstViewController and secondViewController has no connection or anything.
Picture
I used this code
#IBAction func buttonTapped(sender: UIButton) {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("secondViewCtrl") as! SecondViewController
self.presentViewController(vc, animated: true, completion: nil)
}
The reason why i instatiate so that I could pass data like
vc.name = "Myname"
The problem with this code is that it doesn't present navigation bar and as well as the tab bar. What should I do to show both?
Updated question
#IBAction func buttonTapped(sender: UIButton) {
guard let tabBarController = tabBarController else { return }
tabBarController.selectedIndex = 1
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("trackYourGenie") as! TrackYourGenieViewController
let navController = tabBarController.viewControllers![1]
let secondViewController = navController.topViewController
vc.name = "Myname"
}
You are instantiating the view controller hence you wouldn't get the navigation bar. To get the navigation bar please instantiate navigation controller and since the second view is only child you would get the second view by default.
#IBAction func buttonTapped(sender: UIButton) {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("Navigation Controller Id") as! UINavigationController
self.presentViewController(vc, animated: true, completion: nil)
}
The above code should give you the navigation bar.
A safe approach:
guard let tabBarController = tabBarController else { return }
tabBarController.selectedIndex = 1
If you need to access to your tabBarController to pass datas you can do simply:
let navController = tabBarController.viewControllers[1]! as! UINavigationController
let secondViewController = navController.topViewController
Your method could be:
#IBAction func buttonTapped(sender: UIButton) {
guard let tabBarController = tabBarController else { return }
let navController = tabBarController.viewControllers[1]! as! UINavigationController
let secondViewController = navController.topViewController as! SecondViewController
secondViewController.name = "my name"
tabBarController.selectedIndex = 1
}
In your case, the following code should be sufficient :
self.tabBarController.selectedIndex = 1
As UITabBarController is your rootViewController, you can access it with self.tabBarController. You don't have to instantiate UINavigationController as it is in the storyboard.
I can see from your StoryBoard that you have a TabBarController. If your configuration is that and FirstViewController is on first tab and SecondViewController on second tab, you can just change TabBarController selectedIndex property:
#IBAction func buttonTapped(sender: UIButton) {
tabBarController?.selectedIndex = 1
}
If you want to pass data to SecondViewController you can try one of these solutions:
let controller = tabBarController.viewControllers[1] as SecondViewController!
controller.data = "some data"
This soultion could not work since SecondViewController is not ready yet.
Create a singleton class where to save data, then retrieve data in SecondViewController viewDidLoad method
Save data in UserDefaults, then retrieve data in SecondViewController viewDidLoad method (bad solution if information doesn't have to be persistent)
Extend UITabBarController and use it, create a custom var in tabBarController, put data in that variable and then retrieve data in SecondViewController viewDidLoad method
Then clear data if needed.
Navigation will not work from firstViewController as to navigate something we need UINavigationController.
Try Like This
I have a tab bar, whose items I want to change depending on a user's settings. So I need to be able to add/remove items from the tab bar programmatically. Here is my code:
class TabBarViewController: UITabBarController {
var controllerArray = [UIViewController]()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
self.tabBar.tintColor = UIColor.greenColor()
let storyBoard = UIStoryboard(name: "Main", bundle: NSBundle.mainBundle())
let controller1 = storyBoard.instantiateViewControllerWithIdentifier("Navigation2") as! nav2
let controller2 = storyBoard.instantiateViewControllerWithIdentifier("Explore") as! ExploreNavigation
let controller3 = storyBoard.instantiateViewControllerWithIdentifier("friends") as! ExploreNav
let controller4 = storyBoard.instantiateViewControllerWithIdentifier("controller3ID") as! controller3VC
controllerArray.append(controller1)
controllerArray.append(controller2)
controllerArray.append(controller3)
controllerArray.append(controller4)
self.tabBarController?.setViewControllers(controllerArray, animated: true)
}
}
but if I comment out one of the lines, for example like this:
//controllerArray.append(controller2)
so that that controller is not apart of the controllersArray, the controller still displays in the tab bar. What am I doing wrong?
I also tried this, and it didn't work either:
self.tabBarController?.viewControllers = controllerArray
Just say
self.setViewControllers(controllerArray, animated: true)
instead of
self.tabBarController?.setViewControllers(controllerArray, animated: true)
You are subclassing UITabBarController not UIViewController so you don't have, or at least don't need, the property tabBarController.