In my scenario, I need to pass UIVIewController name and some more string values to particular function. I tried below code but not getting result.
Passing Parameters To Particular Function
self.accountoptionscall(vcName: UIViewController(), vcIdentifier: "profileviewcontroller", popUpVC: ProfileViewController.self)
func accountoptionscall<T: UIViewController>(vcName: UIViewController,vcIdentifier: String, popUpVC: T.self) {
let viewcontrollers = self.storyboard!.instantiateViewController(withIdentifier: vcIdentifier) as! vcName
let navController = UINavigationController(rootViewController: viewcontrollers)
self.present(navController, animated:true, completion: nil)
}
I use it in my app, I think it can help you.
extension UIViewController {
/// Load UIViewController type from UIStoryboard
class func loadFromStoryboard<T: UIViewController>() -> T {
let name = String(describing: T.self)
let storybord = UIStoryboard(name: name, bundle: nil)
if let viewController = storybord.instantiateInitialViewController() as? T {
return viewController
} else {
fatalError("Error: No initial view controller in \(name) storyboard!")
}
}
}
Here how you can use it:
func loadVC<T: UIViewController>(controller: T) {
let vc: T = T.loadFromStoryboard()
let navigationVC = UINavigationController(rootViewController: vc)
self.present(navController, animated:true, completion: nil)
// or if use in appDelegate you can do it: window?.rootViewController = navigationVC
}
Related
I am attempting to write a func that 1) instantiates a subclass of UIViewController and 2) pushes into the navigation controller of the caller UIViewController.
So far, I have this:
func pushAnyViewController<T>(viewController:T, storyboardName:String) {
// Instantiate the view controller of type T
guard let nextViewController = UIStoryboard(name: storyboardName, bundle: nil).instantiateViewController(withIdentifier: String(describing: T.self)) as? T else {
return
}
viewController.navigationController.pushViewController(nextViewController, animated: true)
}
This produces error
Value of type 'T' has no member 'navigationController'
I am not sure if somehow I should say that T will always be a subclass of UIViewController. If that is the case, it's not clear where I do that. For this, I thought about:
func pushAnyViewController<T>(viewController:T & UIViewController, storyboardName:String)
but that produces errors:
Generic parameter 'T' is not used in function signature
Non-protocol, non-class type 'T' cannot be used within a protocol-constrained type
You need to identify that T is a vc with <T:UIViewController>
func pushAnyViewController<T:UIViewController>(viewController:T, storyboardName:String) {
guard let nextViewController = UIStoryboard(name: storyboardName, bundle: nil).instantiateViewController(withIdentifier: String(describing: T.self)) as? T else { return }
viewController.navigationController?.pushViewController(nextViewController, animated: true)
}
The top answer didn't suit me, I needed a more generic solution. First, I needed the option to pass data, second, I wanted to have a generic function that can push or present VC, and last, I wanted that my generic function can be called from anywhere, not just from the UIViewController, that's why an extension of UIViewController didn't suit me.
I decided to create a struct with simple init, and two public methods so that I can create the copy anywhere and call those methods.
struct Navigator {
// MARK: - DisplayVCType enum
enum DisplayVCType {
case push
case present
}
// MARK: - Properties
private var viewController: UIViewController
static private let mainSBName = "Main"
// MARK: - Init
init(vc: UIViewController) {
self.viewController = vc
}
// MARK: - Public Methods
public func instantiateVC<T>(withDestinationViewControllerType vcType: T.Type,
andStoryboardName sbName: String = mainSBName) -> T? where T: UIViewController {
let storyBoard: UIStoryboard = UIStoryboard(name: sbName, bundle: nil)
let destinationVC = storyBoard.instantiateViewController(withIdentifier: String(describing: vcType.self))
return destinationVC as? T
}
public func goTo(viewController destinationVC: UIViewController,
withDisplayVCType type: DisplayVCType = .present,
andModalPresentationStyle style: UIModalPresentationStyle = .popover) {
switch type {
case .push:
viewController.navigationController?.pushViewController(destinationVC, animated: true)
case .present:
destinationVC.modalPresentationStyle = style
viewController.present(destinationVC, animated: true, completion: nil)
}
}
}
and example call in some VC, with passing string after push:
class SomeVC: UIViewController {
var navigator: Navigator?
override func viewDidLoad() {
super.viewDidLoad()
navigator = Navigator(vc: self)
}
func pushVC() {
guard let vc = navigator?.instantiateVC(withDestinationViewControllerType: VC1.self) else { return }
vc.someString = "SOME STRING TO BE PASSED"
navigator?.goTo(viewController: vc, withDisplayVCType: .push)
}
func presentVC() {
guard let vc = navigator?.instantiateVC(withDestinationViewControllerType: TableViewController.self) else { return }
navigator?.goTo(viewController: vc, withDisplayVCType: .present)
}
}
With Help of some keyword.
enum Storyboard : String {
case Main
}
func viewController(_ viewController: UIViewController.Type) -> some UIViewController {
return UIStoryboard(name: self.rawValue, bundle: nil).instantiateViewController(withIdentifier: String(describing: viewController.self))
}
nil Delegate between two ViewController with two different Bundle using swift 4 (commented in second code)
here is my code :
First ViewController :
class FirstVC : UIViewController, MerchantResultObserver{
var secVC = SecondVC()
override func viewDidLoad() {
secVC.delegate = self
let storyboard = UIStoryboard(name: “SecondVC”, bundle: Bundle(identifier: “SecondBundle”))
let controller = storyboard.instantiateInitialViewController()
self.present(controller!, animated: true, completion: nil)
secVC.initSecondVC(data)
}
func Error(data: String) {
print("-------------Error Returned------------- \(data)")
}
func Response(data: String) {
print("-------------Response Returned------------- \(data)")
}
}
Second ViewController :
public class SecondVC: UIViewController {
public weak var delegate: MerchantResultObserver!
public func initSecondVC(_ data : String){
print(data)
}
#IBAction func sendRequest(_ sender: UIButton) {
delegate?.Response(data: “dataReturnedSuccessfully”) // delegate is nil //
dismiss(animated: true, completion: nil) // returned to FirstVC without returning “dataReturnedSuccessfully” //
}
}
public protocol MerchantResultObserver: class{
func Response(data : String)
func Error(data : String)
}
Any help would be appreciated
var secVC = SecondVC()
and
let storyboard = UIStoryboard(name: “SecondVC”, bundle: Bundle(identifier: “SecondBundle”))
let controller = storyboard.instantiateInitialViewController() as? SecondVC
These both are different instances.
You can assign a delegate to the controller, like
controller.delegate = self
It will call the implemented delegate methods in First View Controller.
Full Code.
let storyboard = UIStoryboard(name: “SecondVC”, bundle: Bundle(identifier: “SecondBundle”))
if let controller = storyboard.instantiateInitialViewController() as? SecondVC {
//Assign Delegate
controller.delegate = self
//It's not init, but an assignment only, as per your code.
controller.initSecondVC(data)
self.present(controller, animated: true, completion: nil)
}
One more thing, Don't present View in ViewDidLoad. You can put a code in some button or in a delay method.
I am using this code for push SHOW and MODALLY programmatically in iOS Objective C.
And now want to know about Swift 3.
NewsDetailsViewController *vc = instantiateViewControllerWithIdentifier:#"NewsDetailsVCID"];
vc.newsObj = newsObj;
//--this(SHOW)
[self.navigationController pushViewController:vc animated:YES];
//-- or this(MODAL)
[self presentViewController:vc animated:YES completion:nil];
Push
do like
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("NewsDetailsVCID") as NewsDetailsViewController
vc.newsObj = newsObj
navigationController?.pushViewController(vc,
animated: true)
or safer
if let viewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "NewsDetailsVCID") as? NewsDetailsViewController {
viewController.newsObj = newsObj
if let navigator = navigationController {
navigator.pushViewController(viewController, animated: true)
}
}
present
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = self.storyboard?.instantiateViewControllerWithIdentifier("NewsDetailsVCID") as! NewsDetailsViewController
vc.newsObj = newsObj
present(vc!, animated: true, completion: nil)
or safer
if let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "NewsDetailsVCID") as? NewsDetailsViewController
{
vc.newsObj = newsObj
present(vc, animated: true, completion: nil)
}
With an elegant way.
Create an Navigatable protocol:
protocol Navigatable {
/// Storyboard name where this view controller exists.
static var storyboardName: String { get }
/// Storyboard Id of this view controller.
static var storyboardId: String { get }
/// Returns a new instance created from Storyboard identifiers.
static func instantiateFromStoryboard() -> Self
}
Create a default instantiate controller implementation:
/**
Extension of Navigatable protocol with default implementations.
*/
extension Navigatable {
static func instantiateFromStoryboard() -> Self {
let storyboard = UIStoryboard(name: self.storyboardName, bundle: nil)
guard
let viewController = storyboard
.instantiateViewController(withIdentifier: self.storyboardId) as? Self else {
fatalError("Cannot instantiate the controller.")
}
return viewController
}
}
Extends the UIViewController to push a view controller:
extension UIViewController {
/**
Pushes a view controller of the provided type.
- Parameter viewControllerType: Type of view controller to push.
- Parameter completion: Function to be executed on completion.
Contains the view controller that was pushed when successful and nil otherwise.
*/
func pushViewControllerOfType<T: Navigatable>(viewControllerType: T.Type, completion: (T) -> Void) {
let viewController = T.instantiateFromStoryboard()
if let vc = viewController as? UIViewController {
self.pushViewController(vc, animated: true)
}
completion(viewController)
}
/**
Pushes a view controller of the provided type.
- Parameter viewControllerType: Type of view controller to push.
*/
func pushViewControllerOfType<T: Navigatable>(viewControllerType: T.Type) {
self.pushViewControllerOfType(viewControllerType: viewControllerType) { _ in }
}
}
Then you can use the Navigatable protocol for a specific view controller.
class MySuperViewController {
override func viewDidLoad() {
...
}
// ...
}
extension MySuperViewController: Navigatable {
static var storyboardName: String {
return "Main"
}
static var storyboardId: String {
return "MySuperViewControllerId" // From your story board name Main
}
}
// Instantiate your controller
let vc = MySuperViewController.instantiateFromStoryboard()
// Or
//
// Push your view controller
// testViewController.swift
self.pushViewControllerOfType(viewControllerType: MySuperViewController)
//Create object of view controller
let obj = self.storyboard?.instantiateViewController(withIdentifier: "ViewControllerIdentifier”) as! ViewControllerName
//Push Controller
self.navigationController?.pushViewController(obj, animated: true)
//Present Controller
self.navigationController?.present(obj, animated: true, completion: nil)
I have a class 'MyViewController.swift' and a string "MyViewController". How can I create an instance of that viewController from the string and push it in the navigation controller?
I've checked this answer (How to create an object depending on a String in Swift?) but it doesn't seem to do the trick.
Assuming you are working with storyboard, you could extend UIStoryboard like:
class func mainStoryboard() -> UIStoryboard {
return UIStoryboard(name: "Main", bundle: NSBundle.mainBundle())
}
class func myViewController(s: String) -> UIViewController? {
return mainStoryboard().instantiateViewControllerWithIdentifier(s) as? UIViewController
}
and then you can use it like
myVC = UIStoryboard.myViewController("controller")
myVC.view.frame = view.frame
view.addSubview(myVC.view)
addChildViewController(myVC)
myVC.didMoveToParentViewController(self)
or
let vc = getVC("controller")
vc!.modalTransitionStyle = UIModalTransitionStyle.CrossDissolve
self.presentViewController(vc!, animated: true, completion: nil)
Update:
If you are not using storyboards, you can add a something like this to your controller:
func getVC(s: String) -> UIViewController {
switch s {
case "myVc":
return MyVC() as! UIViewController
default:
// handle default case
}
}
I'm trying to present a ViewController if there is any saved data in the data model. But I get the following error:
Warning: Attempt to present * on *whose view is not in the window hierarchy"
Relevant code:
override func viewDidLoad() {
super.viewDidLoad()
loginButton.backgroundColor = UIColor.orangeColor()
var request = NSFetchRequest(entityName: "UserData")
request.returnsObjectsAsFaults = false
var appDel:AppDelegate = (UIApplication.sharedApplication().delegate as AppDelegate)
var context:NSManagedObjectContext = appDel.managedObjectContext!
var results:NSArray = context.executeFetchRequest(request, error: nil)!
if(results.count <= 0){
print("Inga resultat")
} else {
print("SWITCH VIEW PLOX")
let internVC = self.storyboard?.instantiateViewControllerWithIdentifier("internVC") as internViewController
self.presentViewController(internVC, animated: true, completion: nil)
}
}
I've tried different solutions found using Google without success.
At this point in your code the view controller's view has only been created but not added to any view hierarchy. If you want to present from that view controller as soon as possible you should do it in viewDidAppear to be safest.
In objective c:
This solved my problem when presenting viewcontroller on top of mpmovieplayer
- (UIViewController*) topMostController
{
UIViewController *topController = [UIApplication sharedApplication].keyWindow.rootViewController;
while (topController.presentedViewController) {
topController = topController.presentedViewController;
}
return topController;
}
Swift 3
I had this keep coming up as a newbie and found that present loads modal views that can be dismissed but switching to root controller is best if you don't need to show a modal.
I was using this
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard?.instantiateViewController(withIdentifier: "MainAppStoryboard") as! TabbarController
present(vc, animated: false, completion: nil)
Using this instead with my tabController:
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let view = storyboard.instantiateViewController(withIdentifier: "MainAppStoryboard") as UIViewController
let appDelegate = UIApplication.shared.delegate as! AppDelegate
//show window
appDelegate.window?.rootViewController = view
Just adjust to a view controller if you need to switch between multiple storyboard screens.
Swift 3.
Call this function to get the topmost view controller, then have that view controller present.
func topMostController() -> UIViewController {
var topController: UIViewController = UIApplication.shared.keyWindow!.rootViewController!
while (topController.presentedViewController != nil) {
topController = topController.presentedViewController!
}
return topController
}
Usage:
let topVC = topMostController()
let vcToPresent = self.storyboard!.instantiateViewController(withIdentifier: "YourVCStoryboardID") as! YourViewController
topVC.present(vcToPresent, animated: true, completion: nil)
for SWIFT
func topMostController() -> UIViewController {
var topController: UIViewController = UIApplication.sharedApplication().keyWindow!.rootViewController!
while (topController.presentedViewController != nil) {
topController = topController.presentedViewController!
}
return topController
}
You just need to perform a selector with a delay - (0 seconds works).
override func viewDidLoad() {
super.viewDidLoad()
perform(#selector(presentExampleController), with: nil, afterDelay: 0)
}
#objc private func presentExampleController() {
let exampleStoryboard = UIStoryboard(named: "example", bundle: nil)
let exampleVC = storyboard.instantiateViewController(withIdentifier: "ExampleVC") as! ExampleVC
present(exampleVC, animated: true)
}
Swift 4
func topMostController() -> UIViewController {
var topController: UIViewController = UIApplication.shared.keyWindow!.rootViewController!
while (topController.presentedViewController != nil) {
topController = topController.presentedViewController!
}
return topController
}
Use of main thread to present and dismiss view controller worked for me.
DispatchQueue.main.async { self.present(viewController, animated: true, completion: nil) }
I was getting this error while was presenting controller after the user opens the deeplink.
I know this isn't the best solution, but if you are in short time frame here is a quick fix - just wrap your code in asyncAfter:
DispatchQueue.main.asyncAfter(deadline: .now() + 0.7, execute: { [weak self] in
navigationController.present(signInCoordinator.baseController, animated: animated, completion: completion)
})
It will give time for your presenting controller to call viewDidAppear.
For swift 3.0 and above
public static func getTopViewController() -> UIViewController?{
if var topController = UIApplication.shared.keyWindow?.rootViewController
{
while (topController.presentedViewController != nil)
{
topController = topController.presentedViewController!
}
return topController
}
return nil}
let storyboard = UIStoryboard(name: "test", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "teststoryboard") as UIViewController
UIApplication.shared.keyWindow?.rootViewController?.present(vc, animated: true, completion: nil)
This seemed to work to make sure it's the top most view.
I was getting an error
Warning: Attempt to present myapp.testController: 0x7fdd01703990 on myapp.testController: 0x7fdd01703690 whose view is not in the window hierarchy!
Hope this helps others with swift 3
I have tried so many approches! the only useful thing is:
if var topController = UIApplication.shared.keyWindow?.rootViewController
{
while (topController.presentedViewController != nil)
{
topController = topController.presentedViewController!
}
}
All implementation for topViewController here are not fully supporting cases when you have UINavigationController or UITabBarController, for those two you need a bit different handling:
For UITabBarController and UINavigationController you need a different implementation.
Here is code I'm using to get topMostViewController:
protocol TopUIViewController {
func topUIViewController() -> UIViewController?
}
extension UIWindow : TopUIViewController {
func topUIViewController() -> UIViewController? {
if let rootViewController = self.rootViewController {
return self.recursiveTopUIViewController(from: rootViewController)
}
return nil
}
private func recursiveTopUIViewController(from: UIViewController?) -> UIViewController? {
if let topVC = from?.topUIViewController() { return recursiveTopUIViewController(from: topVC) ?? from }
return from
}
}
extension UIViewController : TopUIViewController {
#objc open func topUIViewController() -> UIViewController? {
return self.presentedViewController
}
}
extension UINavigationController {
override open func topUIViewController() -> UIViewController? {
return self.visibleViewController
}
}
extension UITabBarController {
override open func topUIViewController() -> UIViewController? {
return self.selectedViewController ?? presentedViewController
}
}
The previous answers relate to the situation where the view controller that should present a view 1) has not been added yet to the view hierarchy, or 2) is not the top view controller.
Another possibility is that an alert should be presented while another alert is already presented, and not yet dismissed.
Swift Method, and supply a demo.
func topMostController() -> UIViewController {
var topController: UIViewController = UIApplication.sharedApplication().keyWindow!.rootViewController!
while (topController.presentedViewController != nil) {
topController = topController.presentedViewController!
}
return topController
}
func demo() {
let vc = ViewController()
let nav = UINavigationController.init(rootViewController: vc)
topMostController().present(nav, animated: true, completion: nil)
}
Swift 5.1:
let storyboard = UIStoryboard.init(name: "Main", bundle: Bundle.main)
let mainViewController = storyboard.instantiateViewController(withIdentifier: "ID")
let appDeleg = UIApplication.shared.delegate as! AppDelegate
let root = appDeleg.window?.rootViewController as! UINavigationController
root.pushViewController(mainViewController, animated: true)
Rather than finding top view controller, one can use
viewController.modalPresentationStyle = UIModalPresentationStyle.currentContext
Where viewController is the controller which you want to present
This is useful when there are different kinds of views in hierarchy like TabBar, NavBar, though others seems to be correct but more sort of hackish
The other presentation style can be found on apple doc