I have two ViewControllers connected via Show segue. I need to pass NSSlider's value from ViewController to SecondViewCotroller.
So, moving slider in ViewController a variable updates in SecondViewController.
How to update a value of imagesQty variable?
// FIRST VIEW CONTROLLER
import Cocoa
class ViewController: NSViewController {
#IBOutlet weak var slider: NSSlider!
#IBOutlet weak var photosLabel: NSTextField!
#IBAction func segueData(_ sender: NSSlider) {
photosLabel.stringValue = String(slider.intValue) + " photos"
self.performSegue(withIdentifier: NSStoryboardSegue.Identifier(rawValue: "SegueIdentifierForSecondVC"), sender: slider)
}
func prepare(for segue: NSStoryboardSegue, sender: NSSlider?) {
if segue.identifier!.rawValue == "SegueIdentifierForSecondVC" {
if let secondViewController =
segue.destinationController as? SecondViewController {
secondViewController.imagesQty = slider.integerValue
}
}
}
}
and
// SECOND VIEW CONTROLLER
import Cocoa
class SecondViewController: NSViewController {
var imagesQty = 30
override func viewWillAppear() {
super.viewWillAppear()
self.view.wantsLayer = true
print("viewWillAppear – Qty:\(imagesQty)")
//let arrayOfViews: [NSImageView] = [view01...view12]
let url = URL(fileURLWithPath: NSHomeDirectory()).appendingPathComponent("Desktop/ArrayOfElements")
do {
let fileURLs = try FileManager.default.contentsOfDirectory(at: url, includingPropertiesForKeys: nil, options: [.skipsHiddenFiles]).reversed()
let photos = fileURLs.filter { $0.pathExtension == "jpg" }
for view in arrayOfViews {
//"imagesQty" is here
let i = Int(arc4random_uniform(UInt32(imagesQty-1)))
let image = NSImage(data: try Data(contentsOf: photos[i]))
view.image = image
view.imageScaling = .scaleNone
}
} catch {
print(error)
}
}
First of all the purpose and benefit of NSStoryboardSegue.Identifier is to create an extension to be able to avoid literals.
extension NSStoryboardSegue.Identifier {
static let secondVC = NSStoryboardSegue.Identifier("SegueIdentifierForSecondVC")
}
Then you can write
self.performSegue(withIdentifier: .secondVC, sender: slider)
and
if segue.identifier! == .secondVC { ...
This error occurs because imagesQty is declared in viewWillAppear rather than on the top level of the class.
Change it to
class SecondViewController: NSViewController {
var imagesQty = 30 // Int is inferred
// override func viewWillAppear() {
// super.viewWillAppear()
// }
}
There is another mistake: The signature of prepare(for segue is wrong. It must be
func prepare(for segue: NSStoryboardSegue, sender: Any?) {
You can‘t change the value because the var is defined in the function and not in the class.
Make your var a class property and it should work.
class SecondViewController: UIViewController {
var imagesQty: Int = 30
...
}
Related
I'm having users fill out some profile information via texts fields (name, email, etc.), which is used to set my ProfileContoller.shared.profile values. When I get to my navigation segue to pass the data over, my destinationVC.profile will not set its value to the sending profile object and I get nil instead.
My sendingVC is embedded in a navigation controller, while my destinationVC is embedded in Tab Bar Controller.
Segue SendingVC
Attributes Inspector SendingVC
DestinationVC
// Sending View Controller:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
guard let profile = ProfileController.shared.profile else { return }
if segue.identifier == "signUpMemicTBC" {
let destinationVC = segue.destination as? ProfileViewController
destinationVC?.profile = profile
// Receiving ProfileViewController:
class ProfileViewController: UIViewController {
// MARK: - IBOutlets
#IBOutlet weak var fullNameLabel: UILabel!
#IBOutlet weak var usernameLabel: UILabel!
#IBOutlet weak var emailLabel: UILabel!
// MARK: - Landing Pad
var profile : Profile? {
didSet {
updateViews()
}
}
override func viewDidLoad() {
super.viewDidLoad()
updateViews()
}
func updateViews () {
guard let profile = profile else { return }
fullNameLabel.text = profile.firstName + " " + profile.lastName
usernameLabel.text = profile.username
emailLabel.text = profile.email
}
}
// ProfileController:
class ProfileController {
// MARK: - Properties
var profile : Profile?
// MARK: - Singleton
static let shared = ProfileController()
}
My sending object has data:
(lldb) po profile
Profile: 0x600000c873c0
The destination object is unexpectedly nil:
(lldb) po destinationVC?.profile
nil
didSet triggers while your vc in segue isn't loaded yet so all outlets are nil
you need to put updateViews() inside viewDidLoad
Plus your destination is a tabBar
let tab = segue.destination as! UITabBarController
let destinationVC = tab.viewControllers![2] as! ProfileViewController
I think all you have to do is call the updateViews() in the main thread.
didSet {
print("did set profile called")
DispatchQueue.main.async{[weak self] in
guard let self = self else {
return
}
self.updateViews()
}
}
Another option would be to update the views in viewDidLoad()
override func viewDidLoad() {
if let prof = self.profile {
self.updateViews()
}
}
You can use below code to safely pass data to the ProfileViewController.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
guard let profile = ProfileController.shared.profile else { return }
if segue.identifier == "signUpMemicTBC" {
guard let tabBarController = segue.destination as? UITabBarController else { return }
guard let profileController = tabBarController.viewControllers?.index(at: 2) as? ProfileViewController else {
return
}
profileController.profile = profile
}
}
I am currently using a container view and I want to change the value of parent view controller imageView through child view controller using delegates, but it always returns nil.
import UIKit
protocol updateImage {
func userIsDone(image:UIImage)
}
class ViewController: UIViewController, updateImage{
#IBOutlet weak var imageView:UIImageView!
var image = UIImage(named: "hello.png")
override func viewDidLoad() {
super.viewDidLoad()
self.imageView.image=self.image
}
func userIsDone(image: UIImage) {
self.image=image
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "containerChild"{
let nextView = segue.destinationViewController as! ControllerChild
nextView.image=self.image
nextView.delegate=self
}
}
}
class ControllerChild:UIViewController{
var image=UIImage(named: "newhello.png")
var delegate: updateImage? = nil
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func changeImage(sender:UIButton){
if(delegate != nil){
self.delegate!.userIsDone(self.image!)
print("I am Called!")
}
}
}
Remove this line:
nextView.image = image
And change the userIsDone function to:
func userIsDone(image: UIImage) {
imageView.image = image
}
As side notes:
In Swift you don't need to use self outside of blocks/closures. For example, you don't need to self.imageView.image = self.image -- just imageView.image = image will do.
Protocols should be upper-cased, like UpdateImage (instead of updateImage).
You don't need that extra .png to reference images, just the title, E.g.: "hello".
Apple describes Swift code conventions in their awesome Swift book.
Here is the code, refactored (Swift 3):
import UIKit
protocol UpdateImageProtocol {
func userIsDone(image: UIImage)
}
class ViewController: UIViewController, UpdateImageProtocol {
#IBOutlet weak var imageView: UIImageView!
var image = UIImage(named: "hello")
override func viewDidLoad() {
super.viewDidLoad()
userIsDone(image: image!)
}
func userIsDone(image: UIImage) {
imageView.image = image
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "containerChild" {
let nextView = segue.destination as! ChildViewController
nextView.delegate = self
}
}
}
class ChildViewController: UIViewController {
var image = UIImage(named: "newHello")
var delegate: UpdateImageProtocol?
#IBAction func changeImage(sender: UIButton) {
delegate?.userIsDone(image: image!)
}
}
I have what is basically a notes app, and I am trying to call a function that is in one view controller from another. How do I do this, or is there a better way I should do it?
Here's where I am trying to call the function from
class NoteDetailViewController: UIViewController
{
#IBOutlet weak var funcButton: UIButton!
#IBAction func funcButTouched(sender: UIButton)
{
// where i want to call the function
}
}
And where the function is
class ListTableViewController: UITableViewController
{
// the function
func wordCount()
{
var contentArr = Project.sharedInstance.content.componentsSeparatedByString(" ")
for (index, element) in contentArr.enumerate()
{
let location = conciseArr.indexOf(element)
if (location != nil)
{
contentArr[index] = inflatedArr[location!]
afterStr = contentArr.joinWithSeparator(" ")
Project.sharedInstance.after = afterStr
}
}
}
}
I've tried just creating an instance of ListTableViewController and just calling the function that way but I get an error.
You could use delegation.
First, declare a delegate protocol. This should be in your NoteDetailViewController.swift file but outside of the class declaration:
protocol NoteDetailViewControllerDelegate: class {
func noteDetailViewControllerButtonTouched(controller: NoteDetailViewController)
}
Next, add a delegate property to your NoteDetailViewController:
weak var delegate: NoteDetailViewControllerDelegate?
Now, we use the #IBAction to tell the delegate, which will be the ListTableViewController:
#IBAction func funcButTouched(sender: UIButton)
{
delegate?.noteDetailViewControllerButtonTouched(self)
}
Finally, back in ListTableViewController (assuming this controller is the one directly before a NoteDetailViewController is shown), conform to the protocol and use prepareForSegue to set the delegate to itself:
class ListTableViewController: UITableViewController, NoteDetailViewControllerDelegate {
// ... more stuff ...
// Implement the delegate protocol
func noteDetailViewControllerButtonTouched(controller: NoteDetailViewController) {
// Do something! The button was pressed!
wordCount()
}
// Set ourselves as delegate when we are about to show the other view controller
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let yourVC = segue.destinationViewController as? NoteDetailViewController {
yourVC.delegate = self
}
}
}
You should finish with something like this:
NoteDetailViewController.swift:
class NoteDetailViewController: UIViewController
{
#IBOutlet weak var funcButton: UIButton!
weak var delegate: NoteDetailViewControllerDelegate?
#IBAction func funcButTouched(sender: UIButton)
{
delegate?.noteDetailViewControllerButtonTouched(self)
}
}
protocol NoteDetailViewControllerDelegate: class {
func noteDetailViewControllerButtonTouched(controller: NoteDetailViewController)
}
ListTableViewController.swift:
class ListTableViewController: UITableViewController, NoteDetailViewControllerDelegate
{
// the function
func wordCount()
{
var contentArr = Project.sharedInstance.content.componentsSeparatedByString(" ")
for (index, element) in contentArr.enumerate()
{
let location = conciseArr.indexOf(element)
if (location != nil)
{
contentArr[index] = inflatedArr[location!]
afterStr = contentArr.joinWithSeparator(" ")
Project.sharedInstance.after = afterStr
}
}
}
// Implement the delegate protocol
func noteDetailViewControllerButtonTouched(controller: NoteDetailViewController) {
// Do something! The button was pressed!
wordCount()
}
// Set ourselves as delegate when we are about to show the other view controller
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let yourVC = segue.destinationViewController as? NoteDetailViewController {
yourVC.delegate = self
}
}
}
Just follow bellow code its very simple :-
NoteDetailViewController.swift:
class NoteDetailViewController: UIViewController
{
#IBOutlet weak var funcButton: UIButton!
var parentListTableView : ListTableViewController!
#IBAction func funcButTouched(sender: UIButton)
{
parentListTableView.wordCount()
}
}
ListTableViewController.swift:
class ListTableViewController: UITableViewController
{
// the function
func wordCount()
{
var contentArr = Project.sharedInstance.content.componentsSeparatedByString(" ")
for (index, element) in contentArr.enumerate()
{
let location = conciseArr.indexOf(element)
if (location != nil)
{
contentArr[index] = inflatedArr[location!]
afterStr = contentArr.joinWithSeparator(" ")
Project.sharedInstance.after = afterStr
}
}
}
// Set ourselves as delegate when we are about to show the other view controller
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let yourVC = segue.destinationViewController as? NoteDetailViewController {
yourVC.parentListTableView = self
}
}
}
I'm working on an app, and need to pass data between view and containerView. I need to send data and receive data from both Views.
Let me explain better:
I can change the Label Master (Touch the Container Button) by protocol, but I can not change the Label Container (Touch the Master button). What happens is the Master connects with the container by a following. But do not have a follow Container linking to the Master.
I tried to add but segue to, but it worked.
The Master View Controller:
import UIKit
protocol MasterToContainer {
func changeLabel(text:String)
}
class Master: UIViewController, ContainerToMaster {
#IBOutlet var containerView: UIView!
var masterToContainer:MasterToContainer?
#IBOutlet var labelMaster: UILabel!
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "containerViewSegue" {
let view = segue.destinationViewController as? Container
view!.containerToMaster = self
}
}
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func button_Container(sender: AnyObject) {
masterToContainer?.changeLabel("Nice! It's work!")
}
func changeLabel(text: String) {
labelMaster.text = text
}
}
The Container View Controller:
import UIKit
protocol ContainerToMaster {
func changeLabel(text:String)
}
class Container: UIViewController, MasterToContainer {
var containerToMaster:ContainerToMaster?
#IBOutlet var labelContainer: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func button_Master(sender: AnyObject) {
containerToMaster?.changeLabel("Amazing! It's work!")
}
func changeLabel(text: String) {
labelContainer.text = text
}
}
Can someone help me?
All you need to do is keep a reference to Container in your master view controller.
That is, you should add an instance variable to Master that will hold a reference to the view controller, not just the view. You'll need to set it in prepareForSegue.
So the beginning of Master View Controller would look something like this:
class Master: UIViewController, ContainerToMaster {
#IBOutlet var containerView: UIView!
var containerViewController: Container?
#IBOutlet var labelMaster: UILabel!
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "containerViewSegue" {
containerViewController = segue.destinationViewController as? Container
containerViewController!.containerToMaster = self
}
}
And then in your button function, simply change the label using the variable you just added.
Example:
#IBAction func button_Container(sender: AnyObject) {
containerViewController?.changeLabel("Nice! It's work!")
}
This means you can get rid of your MasterToContainer protocol too.
I tested this code, so I know it works, but unfortunately I am an Objective-C dev, and know nothing about best practices in Swift. So I don't know if this is the best way to go about it, but it certainly works.
Edit:
Here's the exact code I've tested:
Master.swift:
import UIKit
class Master: UIViewController, ContainerToMaster {
#IBOutlet var containerView: UIView!
#IBOutlet var labelMaster: UILabel!
var containerViewController: Container?
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "containerViewSegue" {
containerViewController = segue.destinationViewController as? Container
containerViewController!.containerToMaster = self
}
}
#IBAction func button_Container(sender: AnyObject) {
containerViewController?.changeLabel("Nice! It's work!")
}
func changeLabel(text: String) {
labelMaster.text = text
}
}
Container.swift:
import UIKit
protocol ContainerToMaster {
func changeLabel(text:String)
}
class Container: UIViewController {
#IBOutlet var labelContainer: UILabel!
var containerToMaster:ContainerToMaster?
#IBAction func button_Master(sender: AnyObject) {
containerToMaster?.changeLabel("Amazing! It's work!")
}
func changeLabel(text: String) {
labelContainer.text = text
}
}
I solved it with this code
To send data from ViewController -> ContainerViewController
Class ViewController : UIViewController {
func sendData(MyStringToSend : String) {
let CVC = childViewControllers.last as! ContainerViewController
CVC.ChangeLabel( MyStringToSend)
}
}
in your ContainerViewController
Class ContainerViewController : UIViewController {
#IBOutlet weak var myLabel: UILabel!
func ChangeLabel(labelToChange : String){
myLabel.text = labelToChange
}
}
To send data from ContainerViewController -> ViewController
Class ContainerViewController : UIViewController {
func sendDataToVc(myString : String) {
let Vc = parentViewController as! ViewController
Vc.dataFromContainer(myString)
}
}
and in ViewController
Class ViewController : UIViewController {
func dataFromContainer(containerData : String){
print(containerData)
}
}
I hope this will help someone.
you can use this extension to access the container child
extension UIViewController {
func getContainerChild<vc:UIViewController>(_ viewController : vc,_ hasNavigation : Bool = true) -> (vc) {
guard let vc = self.children[0] as? UINavigationController else {return viewController}
if hasNavigation {
guard let childVC = vc.children[0] as? PurchasedHistoryListVC else {
return viewController}
return childVC as! vc
} else {
return vc as! vc
}
}
}
so you can do some thing like this in your view Controller
let vc = self.getContainerChild(yourChildViewControllerClass())
vc.functionName()
I have a view that has two text fields and a button.
#IBOutlet var inputURL: UITextField!
#IBOutlet var inputName: UITextField!
#IBAction func submitUrlButton(sender: AnyObject) {
}
and a second view that has two variables:
var submittedURL = ""
var submittedName = ""
println("Name \(submittedName)")
println("URL \(submittedURL)")
In Swift How do I pass the values entered in the two text fields and assign them to those variables in the second view?
Thanks
EDIT FOR THETOM:
import UIKit
class ViewController: UIViewController {
#IBOutlet var inputURL: UITextField!
#IBAction func submitBtn(sender: AnyObject) {
performSegueWithIdentifier("submissionSegue", sender: self)
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
// Create a new variable to store the instance of the next view controller
let destinationVC = segue.destinationViewController as BrandsViewController
destinationVC.submittedURL.text = inputURL.text
}
}
You can use the method prepareForSegue.
In the first view (the one from which the segue is coming from) write the following code :
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
// Create a new variable to store the instance of the next view controller
let destinationVC = segue.destinationViewController as CustomViewController
destinationVC.submittedURL = inputURL.text
destinationVC.submittedName = inputName.text
}
Here CustomViewController is the custom class of the UIViewController to which the segue is going to.
To perform the segue programmatically in your button #IBAction do that :
#IBAction func buttonWasClicked(sender: AnyObject) {
performSegueWithIdentifier("submissionSegue", sender: self)
}
Since your view controllers are linked with segue you can override the prepareForSegue method in first view controller and pass data by doing so
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if (segue.identifier == "secondViewController") { // here secondViewController is your segue identifier
var secondViewController = segue.destinationViewController as SecondViewController // where SecondViewController is the name of your second view controller class
secondViewController.submittedURL = inputURL.text
secondViewController.submittedName = inputName.text
}
}
And to performSegue inside your button action use perfromSegueWithIdentifier method
#IBAction func submitUrlButton(sender: AnyObject) {
//replace identifier with your identifier from storyboard
self.performSegueWithIdentifier("secondViewController", sender: self)
}
The simplest way of accessing values globally not neccessary to pass with segue
First View controller
import UIKit
var submittedURL:NSString? // declare them here
var submittedName:NSString? // Now these two variables are accessible globally
class YourViewController : UIViewController
{
#IBOutlet var inputURL: UITextField!
#IBOutlet var inputName: UITextField!
#IBAction func submitUrlButton(sender: AnyObject) {
if inputURL.text == "" && inputName.text == ""
{
//Show an alert here etc
}
else {
self.submittedURL.text = inputURL.text
self.submittedName.text = inputName.text
}
}
}
SecondView Controller
import UIKit
class SecondviewController: UIViewController
{
//inside viewDidload
println(submittedURL)
println(submittedName)
}