How to present programmatically a view controller from a UIVIew - ios

I am using a Class which is a subclass of MessageView (Swift Message Library) which is inherit from UIView. Inside, I have a UIButton and I want to present programmatically another ViewController through it.
Here is my code below :
import Foundation
import SwiftMessages
import UIKit
class MyClass: MessageView {
var hideBanner: (() -> Void)?
#IBAction func helpButtonPressed(_ sender: UIButton) {
let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let newViewController = storyBoard.instantiateViewController(withIdentifier: "newViewController") as! NewViewController
self.present(newViewController, animated: true, completion: nil)
#IBAction func tryAgainButtonPressed(_ sender: UIButton) {
hideBanner?()
}
open override func awakeFromNib() {
}
}
I have tried this, but it is not working since the UIView do not have the present method.

First get top ViewController using this. Then you can present your viewController.
if var topController = UIApplication.sharedApplication().keyWindow?.rootViewController {
while let presentedViewController = topController.presentedViewController {
topController = presentedViewController
}
// topController now can use for present.
let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let newViewController = storyBoard.instantiateViewController(withIdentifier: "newViewController") as! NewViewController
topController.present(newViewController, animated: true, completion: nil)
}

.present is a method in UIViewController class, that's the reason you cannot present view controller from UIView class.
To achieve this, get the root view controller and present the controller as follows:
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let viewController = appDelegate.window!.rootViewController as! YourViewController
let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let newViewController = storyBoard.instantiateViewController(withIdentifier: "newViewController") as! NewViewController
viewController .present(newViewController, animated: true, completion: nil)

The iOS convention is that only a ViewControllers presents another ViewController.
So the answers above - where the View is finds the current ViewController via UIApplication.sharedApplication().keyWindow?.... will work but is very much an anti-pattern.
The preferred way would be:
Your MyClass view has presentation code only
You must have a ViewController which has a reference to this MyClass view
This ViewController has the #IBAction func tryAgainButtonPressed
From there, you can present the next ViewController

Try this #simple code.
import Foundation
import SwiftMessages
import UIKit
class MyClass: MessageView {
var hideBanner: (() -> Void)?
#IBAction func helpButtonPressed(_ sender: UIButton) {
let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let newViewController = storyBoard.instantiateViewController(withIdentifier: "newViewController") as! NewViewController
UIApplication.shared.keyWindow?.rootViewController?.present(newViewController, animated: true, completion: nil)
}
#IBAction func tryAgainButtonPressed(_ sender: UIButton) {
hideBanner?()
}
open override func awakeFromNib() {
}
}

Here is the example code using delegation pattern.
class YourViewController: UIViewController {
var yourView: MyClass // may be outlet
override func viewDidLoad() {
super.viewDidLoad()
yourView.delegate = self
}
}
protocol MyClassDelegate:class {
func tryAgainButtonDidPressed(sender: UIButton)
}
class MyClass: MessageView {
weak var delegate: MyClassDelegate?
#IBAction func tryAgainButtonPressed(_ sender: UIButton) {
delegate?.tryAgainButtonDidPressed(sender: sender)
}
}

You can achieve this by two ways
Protocol
By giving reference of that view controller to the view when you are initializing view

Sorry for the late reply. MessageView already provides a buttonTapHandler callback for you:
/// An optional button tap handler. The `button` is automatically
/// configured to call this tap handler on `.TouchUpInside`.
open var buttonTapHandler: ((_ button: UIButton) -> Void)?
#objc func buttonTapped(_ button: UIButton) {
buttonTapHandler?(button)
}
/// An optional button. This buttons' `.TouchUpInside` event will automatically
/// invoke the optional `buttonTapHandler`, but its fine to add other target
/// action handlers can be added.
#IBOutlet open var button: UIButton? {
didSet {
if let old = oldValue {
old.removeTarget(self, action: #selector(MessageView.buttonTapped(_:)), for: .touchUpInside)
}
if let button = button {
button.addTarget(self, action: #selector(MessageView.buttonTapped(_:)), for: .touchUpInside)
}
}
}
which is automatically invoked for any button you connect to the button outlet. So the recommended method for presenting another view controller is to have the presenting view controller configure the presentation logic in this callback:
messageView.tapHandler = { [weak self] in
guard let strongSelf = self else { return }
let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let newViewController = storyBoard.instantiateViewController(withIdentifier: "newViewController") as! NewViewController
strongSelf.present(newViewController, animated: true, completion: nil)
}
If your view has more than one button, you can handle them all through buttonTapHandler since it takes a button argument. You just need to configure the target-action mechanism for each button:
otherButton.addTarget(self, action: #selector(MessageView.buttonTapped(_:)), for: .touchUpInside)
Or you can add one callback for each button by duplicating the above pattern.

Related

how to enable the customview controller with view after dismiss Second viewcontroller in swift

I have two view controller
imag
1.first view controller is main and second is CustomAlertviw controller
main view controller is like above image, when I click continues am showing the customalertview controller, like image. when click the enter pin button I have to dismiss view contoller and show the view controller with uiview on main view controller but tried, it's showing the view controller, there one more custom view is not showing it crashing my app
main view code
#IBAction func backButtonClicked(_ sender: UIButton) {
let myAlert = UIStoryboard(name: "CustomAlertview", bundle: nil).instantiateViewController(withIdentifier: "CustomAlertViewController") as? CustomAlertViewController
myAlert?.modalPresentationStyle = UIModalPresentationStyle.overCurrentContext
myAlert?.modalTransitionStyle = UIModalTransitionStyle.crossDissolve
self.present(myAlert!, animated: true, completion: nil)
}
Customalertview controller
#IBAction func enterPinButtonClick(_ sender: Any) {
self.dismiss(animated: true, completion: nil)
let myAlert = UIStoryboard(name: "ScanAndPay", bundle: nil).instantiateViewController(withIdentifier: "ScanAndPayDetailsEntryViewController") as? ScanAndPayDetailsEntryViewController
myAlert?.modalPresentationStyle = UIModalPresentationStyle.overCurrentContext
myAlert?.modalTransitionStyle = UIModalTransitionStyle.crossDissolve
self.present(myAlert!, animated: true, completion: nil)
myAlert.valuespass()
}
inside main view controller one function calling from the customalrerview
func valuespass()
{
DispatchQueue.main.async {
self.authType = 1
self.authStatus = false
print("this is calling")
self.pinStatusLabel.text = "Please enter a 4-digit Security PIN"
}
when I am calling this function from the custom alert view application is crashing and showing the hread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value this error. how to can show the all information after dismissing the custom view controller.
You are almost done. present ScanAndPay from FirstView instead of CustomAlertview.
I have done using Delegate as I think it will be fit in this scenario. Follow below steps -
Step 1:
In FirstViewController ,
Add - CustomAlertviewDelegate something like this -
class FirstViewController: UIViewController, CustomAlertviewDelegate {
Now replace your backButtonClicked method -
#IBAction func backButtonClicked(_ sender: UIButton) {
let myAlert = UIStoryboard(name: "CustomAlertview", bundle: nil).instantiateViewController(withIdentifier: "CustomAlertViewController") as? CustomAlertViewController
myAlert?.modalPresentationStyle = UIModalPresentationStyle.overCurrentContext
myAlert?.modalTransitionStyle = UIModalTransitionStyle.crossDissolve
myAlert.delegate = self
self.present(myAlert!, animated: true, completion: nil)
}
Add a new Delegate method of CustomAlertviewDelegate -
func ScanAndPayView(){
DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
let myAlert = UIStoryboard(name: "ScanAndPay", bundle: nil).instantiateViewController(withIdentifier: "ScanAndPayDetailsEntryViewController") as? ScanAndPayDetailsEntryViewController
myAlert?.modalPresentationStyle = UIModalPresentationStyle.overCurrentContext
myAlert?.modalTransitionStyle = UIModalTransitionStyle.crossDissolve
self.present(myAlert!, animated: true, completion: nil)
}
}
Step 2:
Now time for CustomAlertview ,
Add protocol for delegate top of the Class -
protocol CustomAlertviewDelegate: class {
func ScanAndPayView()
}
class CustomAlertview: UIViewController{
weak var delegate : CustomAlertviewDelegate!
...
override func viewDidLoad() { // Rest of your code
}
Now time to dismiss current view controller and notify FirstViewController for presenting ScanAndPay view Controller -
#IBAction func enterPinButtonClick(_ sender: Any) {
delegate.ScanAndPayView()
self.dismiss(animated: true, completion: nil)
}
Hope it will help you to achieve what you want.

Accessing elements from another view controller comes up nil

I have an alert view that i made using presentr from GitHub. I used a simple view controller that will overlay over the current view controller. Now i have elements such as a UIImage and a UIlabel from the first view controller that needs to be accessed by the alert view controller. But when I click a unbutton in the alert view controller to access the uiimage and text from uilabel from the firstviewcontroller. Here is the code. Can you show me how I can fix this. I can't segue the data because I'm presenting the view controller and the data I'm trying to access is too much too segue anyway. I keep getting this error "fatal error: unexpectedly found nil while unwrapping an Optional value" overtime i click the save button in alertviewcontroller.
class firstviewcontroller: UIViewController{
var photos2: [ImageSource]?
#IBOutlet weak var Label: UIlabel!
#IBOutlet weak var Image: UIImage!
}
class alertviewcontroller: UIViewController{
#IBAction func Save(_ sender: Any) {
dismiss(animated: true, completion: nil)
let storyboard: UIStoryboard = UIStoryboard.init(name: "Main", bundle: nil)
let firstViewController: firstviewcontroller = storyboard.instantiateViewController(withIdentifier: "firstviewcontroller") as! firstviewcontroller
if let image = firstViewController.Image {
imageview.image = image
}
if let label = firstViewController.Label {
label.text = Label.text
}
}
}
The biggest mistake you're making is that you are creating a new instance of firstviewcontroller instead of just accessing the current one.
class alertviewcontroller: UIViewController{
#IBAction func Save(_ sender: Any) {
dismiss(animated: true, completion: nil)
let storyboard: UIStoryboard = UIStoryboard.init(name: "Main", bundle: nil)
let firstViewController: firstviewcontroller = storyboard.instantiateViewController(withIdentifier: "firstviewcontroller") as! firstviewcontroller // This is the mistake
if let image = firstViewController.Image {
imageview.image = image
}
if let label = firstViewController.Label {
label.text = Label.text
}
}
}
What you should do instead is access the presentingViewController since you presented the alertviewcontroller using the present function
The code would look like this
class alertviewcontroller: UIViewController{
#IBAction func Save(_ sender: Any) {
dismiss(animated: true, completion: nil)
let storyboard: UIStoryboard = UIStoryboard.init(name: "Main", bundle: nil)
// NOTE: only do implicit unwrapping `as!` if you're sure that the value you're unwrapping is not `nil` or it is of the correct `data type` cause it might cause your app to crash
let firstViewController: firstviewcontroller = self.presentingViewController as! firstviewcontroller
if let image = firstViewController.Image {
imageview.image = image
}
if let label = firstViewController.Label {
label.text = Label.text
}
}
}
Tip: Please review Swift coding guidelines since there are some minor mistakes regarding your naming of methods, variables, and classes.
Might I am wrong but after review your code I have found this messing statement
let firstViewController: firstviewcontroller = storyboard.instantiateViewController(withIdentifier: "firstviewcontroller") as! firstviewcontroller
In this statement you are creating a new instance of firstviewcontroller not accessing already created instance of firstviewcontroller.
Next, you said
I used a simple view controller that will overlay over the current
view controller
So I have assumed you didn't present or push alertviewcontroller on current viewController, on that behave I suggest you the following solutions
In alertviewcontroller get the instance of topViewController by using this method
class func topViewController(base: UIViewController? = (UIApplication.shared.delegate as! AppDelegate).window?.rootViewController) -> UIViewController? {
if let nav = base as? UINavigationController {
return topViewController(base: nav.visibleViewController)
}
if let tab = base as? UITabBarController {
if let selected = tab.selectedViewController {
return topViewController(base: selected)
}
}
if let presented = base?.presentedViewController {
return topViewController(base: presented)
}
return base
}
then you can transfer your data from alertviewcontroller to topViewController.
Next solution is that you can pass values from alertviewcontroller to firstviewcontroller by using delegates.

Cannot update textfield in delegate callback method

I have implemented delegate in LoginViewController defined in RegistrationViewController. Callback function is calling but the problem is that I am not able to update the textfield of LoginViewController in delegate method.
LoginViewController.swift
import UIKit
class LoginViewController :UIViewController,RegisterViewDelegate {
#IBOutlet weak var mobileNumber: UITextField!
#IBAction func showRegistrationView(_ sender: Any) {
let controller = storyboard?.instantiateViewController(withIdentifier: "registration") as! RegistrationViewController
controller.delegate = self
present(controller, animated: false, completion: nil)
}
func onUserRegistrationCompletion(number: String) {
print(number) // output is 05010101010
DispatchQueue.main.async {
self.mobileNumber.text! = number
print(self.mobileNumber.text!) . // output is empty
}
}
}
RegistrationViewController.swift
import UIKit
class RegistrationViewController: UIViewController {
weak var delegate:RegisterViewDelegate?
#IBAction func register(_ sender: Any) {
self.delegate?.onUserRegistrationCompletion(number: "05010101010")
let controller = self.storyboard?.instantiateViewController(withIdentifier: "login")
present(controller!, animated: false, completion: nil)
}
}
protocol RegisterViewDelegate:class {
func onUserRegistrationCompletion(number:String)
}
it means you allocating the memory again on self.storyboard?.instantiateViewController(withIdentifier: "login") in Register VC, that the reason your delegate is by default goes to nil.
#IBAction func register(_ sender: Any) {
self.delegate?.onUserRegistrationCompletion(number: "05010101010")
self.dismiss(animated: true, completion:nil)
}
I suggest you to use navigationController.
and you can push to next view this way:
let controller = storyboard?.instantiateViewController(withIdentifier: "registration") as! RegistrationViewController
controller.delegate = self
self.navigationController?.pushViewController(controller, animated: true)
and when you want to go back to previous view use this code:
self.delegate?.onUserRegistrationCompletion(number: "05010101010")
self.navigationController?.popViewController(animated: true)
And your result will be:
Check THIS sample for more info.
And don't forget to Embed In your LoginViewController into navigationController from storyboard. as shown in demo project.

How to navigate To a ViewController From xib file of a UIView Class

I have a view in my xib file which contain buttons. i want to move to a ViewController when i will press the button (#IBAction). I have used below code
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let nextViewController = storyBoard.instantiateViewControllerWithIdentifier("About") as! AboutViewController
self.presentViewController(nextViewController, animated: true, completion: nil)
I am getting the error "Value of type 'SlideMenuView' has no member 'presentViewController'.
because my class is a UIView type :
class SlideMenuView: UIView {
}
so how can I navigate to other view controller.
That is beacuase the class you are trying to present from is a UIView and not a UIViewController. It has no Present method.
I'm guessing your view (SlideMenuView) is embedded inside a viewcontroller. what you need to do is implement a delegate, and inform your containing viewController to present next Viewcontroller.
code below:
#protocol SlideMenuViewDelegate: class {
func slideMenuViewAboutButtonClicked(menuView: SlideMenuView)
class SlideMenuView: UIView {
weak var delegate: SlideMenuViewDelegate?
#IBAction func aboutButtonClicked(sender: AnyObject) {
self.delegate?.slideMenuViewAboutButtonClicked(self)
}
now, in your viewController, implement this delegate method:
func slideMenuViewAboutButtonClicked(menuView: SlideMenuView) {
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let nextViewController = storyBoard.instantiateViewControllerWithIdentifier("About") as! AboutViewController
self.presentViewController(nextViewController, animated: true, completion: nil)
}
Also, dont forget to assign the sliderMenuView object the viewcontroller as a delegate.
something like:
self.sliderMenuView.delegate = self // (self == the containing viewController
I did it in a different way. In class file
class SlideMenuView: UIView {
var navigationController: UINavigationController? // Declare a navigation controller variable
// And create a method which take a navigation controller
func prepareScreen(navController: UINavigationController)-> UIView {
navigationController = navController
let nibView = NSBundle.mainBundle().loadNibNamed("SlideMenuView", owner: self, options: nil)[0] as! UIView
self.addSubview(nibView)
return nibView
}
// In Button action
#IBAction func btnAction(sender: UIButton) {
var storyBoard = UIStoryboard(name: "Main", bundle: nil)
let nextViewController = storyBoard!.instantiateViewControllerWithIdentifier("NextViewController") as! UIViewController
navigationController?.pushViewController(nextViewController, animated: true)
}
}
// For calling from UIViewController
slideBarMenuIstance.prepareScreen(self.navigationController!)

How to dismiss the current ViewController and go to another View in Swift

I am new to Swift and I want to know how to dismiss the current view controller and go to another view.
My storyboard is like the following: MainMenuView -> GameViewController -> GameOverView. I want to dismiss the GameViewController to go to the GameOverView, not to the MainMenuView.
I use the following code in my MainMenuView:
#IBAction func StartButton(sender: UIButton) {
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let nextViewController = storyBoard.instantiateViewControllerWithIdentifier("GameViewController") as! GameViewController
self.presentViewController(nextViewController, animated:true, completion:nil)
restGame()
}
In the GameViewController, I use this code, but it doesn't dismiss the GameViewController.
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let nextViewController = storyBoard.instantiateViewControllerWithIdentifier("GameOverView") as! GameOverView
self.presentViewController(nextViewController, animated:true, completion:nil)
This is My GameOverView Code :
class GameOverView: UIViewController{
// save the presenting ViewController
var presentingViewController :UIViewController! = self.presentViewController
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func ReplayButton(sender: UIButton) {
restGame()
didPressClose()
}
#IBAction func ReturnMainMenu(sender: UIButton) {
Data.GameStarted = 1
self.dismissViewControllerAnimated(false) {
// go back to MainMenuView as the eyes of the user
self.presentingViewController.dismissViewControllerAnimated(false, completion: nil);
}
/* let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let nextViewController = storyBoard.instantiateViewControllerWithIdentifier("MainScene") as! MainScene
self.presentViewController(nextViewController, animated:true, completion:nil)*/
}
func restGame(){
Data.score = 0
Data.GameHolder = 3
Data.GameStarted = 1
Data.PlayerLife = 3.0
Data.BonusHolder = 30
Data.BonusTimer = 0
}
func didPressClose()
{
self.self.dismissViewControllerAnimated(true, completion:nil)
}
override func shouldAutorotate() -> Bool {
return false
}
deinit{
print("GameOverView is being deInitialized.");
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Release any cached data, images, etc that aren't in use.
}
override func prefersStatusBarHidden() -> Bool {
return true
}
}
Any suggestions?
What you can do is let the GameOverView be presented, after all when you presenting it the GameViewController is below in the hierarchy, and then in your GameOverView run the following code to close both when you want to dismiss the GameOverView, like in the following way:
#IBAction func ReturnMainMenu(sender: UIButton) {
// save the presenting ViewController
var presentingViewController: UIViewController! = self.presentingViewController
self.dismissViewControllerAnimated(false) {
// go back to MainMenuView as the eyes of the user
presentingViewController.dismissViewControllerAnimated(false, completion: nil)
}
}
The above code need to be called when you want to dismiss the GameOverView.
I hope this help you.
The below code will take you to the main VC, Here's a tried and tested piece of code.
self.view.window!.rootViewController?.dismiss(animated: false, completion: nil)

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