I'm trying to display a custom button for the tab bar item in my Swift project.
I added a png file, called btn_new, to the Assets folder of the Xcode project and tried to display the custom button in the custom tabbar controller class. But I can only see a circle button with the default blue color and no custom image on it in my simulator.
this is the custom tabbar controller class.
import UIKit
class CustomTabBarController: UITabBarController {
var createEventViewController: CreateEventViewController!
override func viewDidLoad() {
super.viewDidLoad()
createEventViewController = CreateEventViewController()
self.delegate = self
self.tabBar.barTintColor = UIColor.customGreen()
}
func createListNC() -> UINavigationController {
let listVC = listViewController()
listVC.tabBarItem = UITabBarItem(title: "", image: UIImage(named: "btn_new"), tag: 0)
return UINavigationController(rootViewController: listVC)
}
func setUpTabbarItems() -> [UIViewController]{
return [createListNC()]
}
}
extension CustomTabBarController: UITabBarControllerDelegate {
func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
if viewController == tabBarController.viewControllers?[0] {
let vc = CreateEventViewController()
let nc = UINavigationController(rootViewController: vc)
nc.modalPresentationStyle = .popover
self.present(nc, animated: true, completion: nil)
return false
}
return true
}
}
I double-checked the name is called exactly "btn_new", so I was not sure why the button is not displayed. Not really sure but, one thing I am concerned about is that I did not set a size for this custom icon. Can anyone tell me how can I display the button image for the tabbar item?
In your CustomTabBarController viewDidload:
let buttonImage: UIImage! = UIImage(named:
"btn_new")!.withRenderingMode(.alwaysOriginal)
(tabBar.items![0] ).selectedImage = buttonImage
Goto Storyboard-> Select tabBarItem on VC(blue selected area)
Related
faced such an issue that the navigation controller is always black even if I change the appearance to light.
Here is how I create it:
class TabBarController: UITabBarController {
override func viewDidLoad() {
super.viewDidLoad()
viewControllers = [
createViewController(for: AssetViewController(), title: NSLocalizedString("Assets", comment: ""), image: UIImage(systemName: "dollarsign.circle")!),
createViewController(for: WalletViewController(), title: NSLocalizedString("Wallets", comment: ""), image: UIImage(systemName: "wallet.pass")!),
]
}
func createViewController(for rootViewController: UIViewController, title: String, image: UIImage) -> UIViewController {
let navController = UINavigationController(rootViewController: rootViewController)
navController.tabBarItem.image = image
navController.navigationBar.prefersLargeTitles = true
rootViewController.navigationItem.title = title
return navController
}
ViewController:
class AssetViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .systemBackground
self.view = CustomView()
}
The other navigation controllers I build the same way, but they are 100% fine.
What could be the problem? Thanks.
Found the problem. I set the backgroundColor and afterward, I set the custom view. Should switch the order. Still weird why other VCs worked fine.
In my iOS app I've a tabBarController and I want to use one of this buttons to PRESENT a viewController, like for instagram "+" item (when you want to add new posts).
Now I've tried with the following code, but when I dismiss viewController, it go to + page, and I don't want this.
I don't know if I explained myself well, but it works like the button on the instagram tabBar.
class TabBarController: UITabBarController, UITabBarControllerDelegate {
var window: UIWindow!
override func viewDidLoad() {
super.viewDidLoad()
tabBar.tintColor = .white
window = UIApplication.shared.connectedScenes
.filter({$0.activationState == .foregroundActive})
.map({$0 as? UIWindowScene})
.compactMap({$0})
.first?.windows
.filter({$0.isKeyWindow}).first
}
func presentView() {
let storyBoard = UIStoryboard(name: "CreateComment", bundle: nil)
let viewController = storyBoard.instantiateViewController(identifier: "NAV_CONTROLLER")
viewController.modalPresentationStyle = .fullScreen
// I tried to use window because I want to present this viewController over all other viewControllers.
window?.rootViewController = self // tabBarController
window?.makeKeyAndVisible()
present(viewController, animated: true, completion: nil)
}
override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {
guard let items = tabBar.items else { return }
switch item {
case items.first: break
case items.second: presentView()
case items.last: break
default: break
}
}
}
I have 3 items in my tab bar, each linked to a separate viewController, and I want them to reset each time I switch between any of these items.
How can I do this?
You can create a subclass for your tab bar controller and perform required actions in it.
class TabBarViewController: UITabBarController, UITabBarControllerDelegate {
override func viewDidLoad() {
super.viewDidLoad()
self.delegate = self
}
func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
let viewController0: UIViewController? = tabBarController.viewControllers?[0] as? UIViewController
let viewController1: UIViewController? = tabBarController.viewControllers?[1] as? UIViewController
let viewController2: UIViewController? = tabBarController.viewControllers?[2] as? UIViewController
switch self.selectedIndex {
case 0:
// Refresh viewController1
// Refresh viewController2
case 1:
// Refresh viewController2
// Refresh viewController3
case 2:
// Refresh viewController0
// Refresh viewController1
default:
break
}
}
}
I am having a bit of an issue with dismissing a modal view presented from a childviewController in a container view. I have a UINavigationController as the rootViewController (MainNavigationController), and present a modal from one of the childViewControllers from the selectedSegmentIndex 1 (secondViewController). The modal is presented fine, but when I dismiss the modal to go back to the secondViewController(a subclass of HomeController) it returns me back to selectedIndex 0, so not the selectedIndex 1 childViewController it was presented from. I would like the modal to dismiss and return the user back to childViewController it was presented from (the secondViewController) and not return back to selectedIndex 0. Thanks in advance!
// NavigationConroller as rootViewController
class MainNavigationController: UINavigationController {
var segmentedController: UISegmentedControl!
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
let vc1 = TravelersFeedVC()
let vc2 = ProfileVC()
if isLoggedIn() {
// assume user is logged in
let homeController = HomeController()
viewControllers = [homeController]
homeController.firstViewController = vc1
homeController.secondViewController = vc2
} else {
perform(#selector(showLoginController), with: nil, afterDelay: 0.01)
}
}
fileprivate func isLoggedIn() -> Bool {
return UserDefaults.standard.isLoggedIn()
}
func showLoginController() {
let loginController = LoginController()
present(loginController, animated: true, completion: {
// perhaps do something here later
})
}
}
// HomeController as parentViewController
class HomeController: UIViewController, FBSDKLoginButtonDelegate {
// child view controllers to put inside content view
var firstViewController: TravelersFeedVC?
var secondViewController: ProfileVC?
private var activeViewController: UIViewController? {
didSet {
removeInactiveViewController(inactiveViewController: oldValue)
updateActiveViewController()
}
}
private func removeInactiveViewController(inactiveViewController: UIViewController?) {
if let inActiveVC = inactiveViewController {
// call before removing child view controller's view from hierarchy
inActiveVC.willMove(toParentViewController: nil)
inActiveVC.view.removeFromSuperview()
// call after removing child view controller's view from hierarchy
inActiveVC.removeFromParentViewController()
}
}
private func updateActiveViewController() {
if let activeVC = activeViewController {
// call before adding child view controller's view as subview
addChildViewController(activeVC)
activeVC.view.frame = contentView.bounds
contentView.addSubview(activeVC.view)
// call before adding child view controller's view as subview
activeVC.didMove(toParentViewController: self)
}
}
// UI elements
lazy var contentView: UIView = {
let tv = UIView()
tv.backgroundColor = UIColor.purple
tv.translatesAutoresizingMaskIntoConstraints = false
tv.layer.masksToBounds = true
return tv
}()
var segmentedController: UISegmentedControl!
override func viewDidLoad() {
super.viewDidLoad()
activeViewController = firstViewController
checkIfUserIsLoggedIn()
view.addSubview(contentView)
setupProfileScreen()
let items = ["Travelers", "Me"]
segmentedController = UISegmentedControl(items: items)
navigationItem.titleView = segmentedController
segmentedController.tintColor = UIColor.black
segmentedController.selectedSegmentIndex = 0
// Add function to handle Value Changed events
segmentedController.addTarget(self, action: #selector(HomeController.segmentedValueChanged(_:)), for: .valueChanged)
navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Sign Out", style: .plain, target: self, action: #selector(handleSignOut))
navigationItem.leftBarButtonItem?.tintColor = UIColor.black
}
// reference to collectionViewController
var travelersFeedVC: TravelersFeedVC!
func segmentedValueChanged(_ sender:UISegmentedControl!)
{
switch segmentedController.selectedSegmentIndex {
case 0:
activeViewController = firstViewController
case 1:
activeViewController = secondViewController
default: // Do nothing
break
}
}
// secondViewcontroller in containerView where modal is presented from
class ProfileVC: UIViewController {
// button to present modal
lazy var placesButton: UIButton = {
let customButton = UIButton(type: .system)
customButton.backgroundColor = UIColor.clear
// customButton.frame = CGRect(x: 150, y: 50, width: 120, height: self.view.frame.height)
customButton.setTitle("## of Places", for: .normal)
customButton.titleLabel?.font = UIFont.boldSystemFont(ofSize: 16)
customButton.setTitleColor(.white, for: .normal)
customButton.addTarget(self, action: #selector(handleShowPlacesVC), for: .touchUpInside)
return customButton
}()
// function to call to present modal
func handleShowPlacesVC() {
let placesVC = PlacesTableVC()
let navigationController = UINavigationController(rootViewController: placesVC)
present(navigationController, animated: true, completion: nil)
}
// modal view to dismiss
override func viewDidLoad() {
super.viewDidLoad()
navigationItem.leftBarButtonItem = UIBarButtonItem(title: "back", style: .plain, target: self, action: #selector(handleCancel))
}
// dismiss modal view to return to secondViewController in childViewController containerView
func handleCancel() {
dismiss(animated: true, completion: nil)
}
When closing the modal dialog the viewDidAppear function in MainNavigationController is called. There you set a new homeController with it's childs. This will trigger a viewDidload in the HomeController with setting of firstViewController. Try to set a breakpoint there and you will see it.
I suggest to avoid content creation in viewDidAppear, use viewDidLoad instead.
Another hint: 'dismiss' is defined as: 'Dismisses the view controller that was presented modally by the view controller.' - If you open for instance an alert above your modal vc it closes the alert, not the modal view (self). A correct implementation has to call dismiss on the presenting controller (same controller that opened it): "presentingViewController?.dismiss()"
It works in your code because apple has implemented a fallback for the case that nothing is presented, but it's a trap that cause some headache sometime.
The chances are that although you're calling present from the child view controller, it isn't in fact handling the presentation. From the Apple docs:
The object on which you call this method may not always be the one that handles the presentation. Each presentation style has different rules governing its behavior. For example, a full-screen presentation must be made by a view controller that itself covers the entire screen. If the current view controller is unable to fulfill a request, it forwards the request up the view controller hierarchy to its nearest parent, which can then handle or forward the request.
Since you're keeping a reference of the active view controller, one solution may be to explicitly set the index upon dismissal.
How to create programmatically tabs from any class extended by UIViewController:
class DashboardTabBarController: UITabBarController {
override func viewDidLoad() {
//here
}
...
}
UPDATE SWIFT 5
One example of how to create an UITabBarController programmatically could be like this:
First we create the UIViewControllers that will be the content for each tab of the tab bar interface. For this example we only create one very simple.
class Item1ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = UIColor.green
self.title = "item1"
print("item 1 loaded")
}
}
Now, the UITabBarController:
We create the new instances of the UIViewControllers that we want to display in the tab bar. Then we create an icon for each instance we have created and then we create an array that contains all UIViewControllers that specify the content for each tab of the tab bar interface. The order of the view controllers in the array corresponds to the display order in the tab bar.
class DashboardTabBarController: UITabBarController, UITabBarControllerDelegate {
override func viewDidLoad() {
super.viewDidLoad()
delegate = self
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
let item1 = Item1ViewController()
let icon1 = UITabBarItem(title: "Title", image: UIImage(named: "someImage.png"), selectedImage: UIImage(named: "otherImage.png"))
item1.tabBarItem = icon1
let controllers = [item1] //array of the root view controllers displayed by the tab bar interface
self.viewControllers = controllers
}
//Delegate methods
func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
print("Should select viewController: \(viewController.title ?? "") ?")
return true;
}
}
If you are using storyboard for the viewcontrollers then you have to write like this in your tabbarcontroller class.
class CustomTabbarController : UITabBarController {
override func viewDidLoad() {
super.viewDidLoad()
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let firstViewController = FirstViewController()
let navigationController = UINavigationController(rootViewController: firstViewController)
navigationController.title = "First"
navigationController.tabBarItem.image = UIImage.init(named: "map-icon-1")
viewControllers = [navigationController]
if let secondViewController = storyboard.instantiateViewController(withIdentifier: "SecondViewController") as? SecondViewController {
let navgitaionController1 = UINavigationController(rootViewController: secondViewController)
navgitaionController1.title = "Second"
navgitaionController1.tabBarItem.image = UIImage.init(named: "second-icon-1")
var array = self.viewControllers
array?.append(navgitaionController1)
self.viewControllers = array
}
}
}
private lazy var tabbarViewController: UITabBarController = {
let tabbarViewController = UITabBarController()
tabbarViewController.setViewControllers([startVC,
offerVC,
benefitsVC,
shopVC,
recipesVC], animated: true)
return tabbarViewController
}()
window?.rootViewController = tabbarViewController