import UIKit
//EventList ViewController
class EventPage: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
}
class EventForm: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
//IBOutlets
#IBOutlet weak var eventNameField: UITextField!
#IBOutlet weak var fromTimePicker: UIDatePicker!
#IBOutlet weak var toTimePicker: UIDatePicker!
#IBOutlet weak var colorPreview: UIView!
#IBAction func cancel(_ sender: Any) {
//empty text field
eventNameField.text = ""
}
#IBAction func save(_ sender: Any) {
if (eventNameField.hasText) {
//fix error handling
eventNameField.backgroundColor = UIColor.systemGray2
//pull data from fields
let text = eventNameField.text!
let fromTime = fromTimePicker.date
let toTime = toTimePicker.date
//initialize object
let currentEvent = EventModel(eventName: text, fromTime: fromTime, toTime: toTime, color: storedColor)
//append to data model
EventDataArray.append(currentEvent)
//transition
present(EventPage(), animated:true)
}
else {
eventNameField.backgroundColor = UIColor.systemRed
}
}
}
I currently have an EventPage class declared as type UIViewController, but upon pressing the save button with a populated text field a transition to a blank ViewController occurs. I've attached the class to the correct ViewController in main.storyboard.
The problem in here is that you are creating a new EventPage but it doesn't inherit from Storyboard.
1
Go to the inspector in your storyboard, select your View Controller, and write an identifier for your View Controller (can be anything)
Write it in Storyboard ID:
2
Replace
present(EventPage(), animated:true)
With
(don't forget to replace 'MYIDENTIFIER' with the id you entered earlier)
let viewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "MYIDENTIFIER") as! EventPage
// If you need to do any configurations to your view controller, do that in here.
// For example:
// viewController.label.text = "Hello, world!"
present(viewController, animated:true)
Note
If the name of your Storyboard file name is not called Main, replace "Main" in step 2 with the name of your storyboard file (excluding .storyboard)
Related
I have a label1 in a view controller of main.storyboard
i have another label2 in view controller of storyboard named Second.storyboard
how can I pass data from one storyboard to another all solutions I can find are about passing data within the same storyboard.Help me with my question.
make a Global variable in Second View Controller
var labelText = ""
While Pushing to secondViewController from First Controller
let secondVC = secondViewController()
secondVC.labelText = label.text // Pass label text from first VC
self.navigationController?.pushViewController(secondVC, animated: true)
Create the instance of Storyboard with the relevant name while creating the instance of SecondViewController in FirsViewController, i.e
class FirsViewController: UIViewController {
#IBOutlet weak var label1: UILabel!
func pushVC2(_ sender: UIButton) {
if let controller = UIStoryboard(name: "Storyboard-2", bundle: nil).instantiateViewController(withIdentifier: "SecondViewController") as? SecondViewController { //here....
controller.str = "Your_Text_Here"
self.navigationController?.pushViewController(controller, animated: true)
}
}
}
Your SecondViewController looks like,
class SecondViewController: UIViewController {
#IBOutlet weak var label2: UILabel!
var str: String?
override func viewDidLoad() {
super.viewDidLoad()
self.label2.text = str
}
}
Via a method or closure, perhaps?
I created a subclass view controller of my superclass/parent view controller and placed labels with placeholder text in that subclass view controller.
I want to set the labels' values to blank strings from the superclass/parent view controller, or, specifically, from an IBAction function that causes the subclass view controller to appear.
Here is the code, first from the parent class, then from the subclass...
'''
class ViewController: UIViewController {
#IBAction func leavingView(){
self.EntryViewController.entryDateLabel.text = ""
self.EntryViewController.entryLabel.text = ""
self.dismiss(animated: true, completion: nil)
}
'''
then from the subclass...
'''
class EntryViewController: ViewController {
#IBOutlet var entryDateLabel: UILabel!
#IBOutlet var entryLabel: UILabel!
}
'''
I have come up with 2 solutions to this problem, without having the parent view controller know about its subclass.
In the first example the parent sets properties on itself that the child listens to (via the didSet method, it then updates its view accordingly. However, this isn't ideal because the entryDate and entry string fields are useless on their own, almost redundant in the parent.
class ParentViewController: UIViewController {
var entryDate: String?
var entry: String?
#IBAction func leavingView(){
self.entryDate = ""
self.entry = ""
self.dismiss(animated: true, completion: nil)
}
}
class ChildViewController: ParentViewController {
#IBOutlet var entryDateLabel: UILabel!
#IBOutlet var entryLabel: UILabel!
override var entryDate: String? {
didSet {
guard isViewLoaded else {
return
}
entryDateLabel.text = entryDate
}
}
override var entry: String? {
didSet {
guard isViewLoaded else {
return
}
entryLabel.text = entry
}
}
}
In my opinion, the second solution is clearer and keeps implementation details more separate because you're using instructions or events to notify the child view controllers.
class ParentViewController: UIViewController {
#IBAction func leavingView(){
self.dismiss(animated: true, completion: didLeaveView)
}
func didLeaveView() { }
}
class ChildViewController: ParentViewController {
#IBOutlet var entryDateLabel: UILabel!
#IBOutlet var entryLabel: UILabel!
override func didLeaveView() {
entryDateLabel.text = ""
entryLabel.text = ""
}
}
Since your requirement is not that much clear I have created a demo for you and into that demo I have added child ContainerViewController into parent ViewController and from that parent view controller you can change UILabel text when you click on UIButton of parent ViewController and code will be for ViewController
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func btnFromParentViewTapped(_ sender: Any) {
//Here get the child of your parent view controller
if let containerView = self.children[0] as? ContainerViewController {
containerView.lblContainer.text = ""
}
}
}
and ContainerViewController code will be:
class ContainerViewController: UIViewController {
#IBOutlet weak var lblContainer: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
}
Don't need to add much here because you are accessing it from parent view.
And your result will be:
As you can see when I click on button which title says Change Container label text the label text from ContainerViewController set to empty string.
For more info check THIS demo project.
I am doing a Mac application, and I have a problem appending text to a NSScrollView when I call a function from a different class.
I have this function on my ViewController class:
import Cocoa
class PopoverVC1: NSViewController {
let popover1 = NSPopover()
class func loadView() ->PopoverVC1 {
let vc = NSStoryboard(name: NSStoryboard.Name(rawValue: "Main"),
bundle: nil).instantiateController(withIdentifier:
NSStoryboard.SceneIdentifier(rawValue: "Popover1")) as! PopoverVC1
vc.popover1.contentViewController = vc
return vc
}
override func viewDidLoad() {
super.viewDidLoad()
popover1.behavior = .transient
popover1.contentViewController = self
}
func showPopover (view: NSView){
popover1.show(relativeTo: view.bounds, of: view, preferredEdge: .maxY)
}
#IBOutlet weak var radioOption1: NSButton!
#IBOutlet weak var radioOption2: NSButton!
#IBOutlet weak var radioOption3: NSButton!
#IBAction func clickOption(_ sender: NSButton) {
switch sender {
case radioOption1: popover1.performClose(sender)
case radioOption2: let vc = ViewController()
vc.myPrint(string: "This is a test")
default: print ("hello")
}
}
}
Than I have a PopoverVC1 class, which is a class to a popover I am using:
import Cocoa
class ViewController: NSViewController {
#IBOutlet weak var oneYes: NSButton!
#IBOutlet weak var oneNo: NSButton!
#IBOutlet weak var notesArea: NSScrollView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override var representedObject: Any? {
didSet {
// Update the view, if already loaded
}
}
func myPrint (string: String){
let mystring = string
let myNotes = notesArea.documentView as? NSTextView
let text = myNotes?.textStorage!
let attr = NSAttributedString(string: mystring)
text?.append(attr)
}
let popover1 = NSPopover()
#IBAction func oneClicked(_ sender: NSButton) {
switch sender {
case oneYes: let vc = PopoverVC1.loadView()
vc.showPopover(view: sender)
case oneNo:
let myNotes = notesArea.documentView as? NSTextView
let text = myNotes?.textStorage!
let attr = NSAttributedString(string: "test")
text?.append(attr)
default: print ("")
}
}
}
However, I got an error when I press the radio button "oneNo" that should call the function "myPrint" and pass the argument.
Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value
I did some tests and when I call this same function "myPrint" from within the ViewCotroller class it works fine.
Any ideas?
Your issue is in clickOption when you are calling:
let vc = ViewController()
vc.myPrint(string: "This is a test")
When you call this method from code and the ViewController's UIViews are set up in a storyboard, the connection from the storyboard is not made. That is why the notesArea is nil when you call the function myPrint. In this case you are creating a new copy of ViewController and it will not be the same one that created the popover.
There are a few ways you can solve the problem that you are trying to accomplish. One of them is known as a delegate. This is a way for you to to call the ViewController's methods like your popover inherited them. You can check out a tutorial here. The idea is that we want to have a reference to the ViewController in your popover so that you can call the functions in the protocol. Then the ViewController that conforms to the protocol will be responsible for handling the method call.
So let's create a protocol called PrintableDelegate and have your ViewController class conform to it. Then in your popover, you will be able to have a reference to the ViewController as a weak var called delegate (you can use what ever name you want but delegate is standard). Then we can call the methods described in the protocol PrintableDelegate, by simply writing delegate?.myPrint(string: "Test"). I have removed some of your irrelevant code from my example.
protocol PrintableDelegate {
func myPrint(string: String)
}
class ViewController : UIViewController, PrintableDelegate {
func myPrint (string: String){
let mystring = string
let myNotes = notesArea.documentView as? NSTextView
let text = myNotes?.textStorage!
let attr = NSAttributedString(string: mystring)
text?.append(attr)
}
#IBAction func oneClicked(_ sender: NSButton) {
let vc = PopoverVC1.loadView()
// Set the delegate of the popover to this ViewController
vc.delegate = self
vc.showPopover(view: sender)
}
}
class PopoverVC1: NSViewController {
// Delegates should be weak to avoid a retain cycle
weak var delegate: PrintableDelegate?
#IBAction func clickOption(_ sender: NSButton) {
// Use the delegate that was set by the ViewController
// Note that it is optional so if it was not set, then this will do nothing
delegate?.myPrint(string: "This is a test")
}
}
I have ViewController, which has a textfield and a button. The user enters his name into the textfield and hits the DONE button. When he hits the button, he is segued to GifteeDetails, which is a different view controller. There is a label in that viewController that is supposed to display his name. But, his name doesn't show up. I don't receive an error.
Here's ViewController:
#IBOutlet weak var textGifteeName: UITextField!
#IBAction func toDetails(_ sender: Any) {
performSegue(withIdentifier: "toDetails", sender: nil)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let destDetails: GifteeDetails = segue.destination as! GifteeDetails
destDetails.nametext = textGifteeName.text!
destDetails.agetext = "\(Int(age)! - 2000 + 17)"
destDetails.locationstext = labelGifteeLocationsPreview.text!
destDetails.intereststext = labelGifteeInterestsPreview.text!
}
Here's GifteeDetails:
var nametext = String()
var agetext = String()
var locationstext = String()
var intereststext = String()
#IBOutlet weak var labelGifteeName: UILabel!
#IBOutlet weak var labelGifteeAge: UILabel!
#IBOutlet weak var labelGifteeLocations: UILabel!
#IBOutlet weak var labelGifteeInterests: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
nametext = labelGifteeName.text!
agetext = labelGifteeAge.text!
locationstext = labelGifteeLocations.text!
intereststext = labelGifteeInterests.text!
}
Sorry about all the !. Swift gives me an error unless I have them.
You are updating the strings nametext and others, which are not connected to your labels.
You need to replace this piece of code:
destDetails.nametext = textGifteeName.text!
destDetails.agetext = "\(Int(age)! - 2000 + 17)"
destDetails.locationstext = labelGifteeLocationsPreview.text!
destDetails.intereststext = labelGifteeInterestsPreview.text!
With:
destDetails.labelGifteeName.text = textGifteeName.text!
destDetails.labelGifteeAge.text = "\(Int(age)! - 2000 + 17)"
destDetails.labelGifteeLocations.text = labelGifteeLocationsPreview.text!
destDetails. labelGifteeInterests.text = labelGifteeInterestsPreview.text!
nametext is a String object, and it is different from labelGifteeName.text which is the String of the label you want to update.
If you use segue then pls remove it, and then create action method of that button in the FirstviewController and use pushViewController to move on the SecondviewController.
Swift 3
Example:
#IBAction func toDetails(_ sender: Any)
{
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "SecondView") as! SecondView
UserDefaults.standard.set(self. textGifteeName.text, forKey: "savedStringKey")
UserDefaults.standard.synchronize()
self.navigationController?.pushViewController(vc,
animated: true)
}
In SecondView:
override func viewDidLoad() {
super.viewDidLoad()
self.labelGifteeName.text = UserDefaults.standard.string(forKey: "savedStringKey")!
}
Please Update your func viewDidLoad() method in GifteeDetailsVC with labelGifteeName.text! = nametext , labelGifteeAge.text!= agetext instead of your code because you have already assigned the value in to strings i.e, nametext and agetext in ViewController, you need to display string value in label
I have a view controller embedded in another VC.
I would like to get the value of a variable from the main VC inside the embedded one. Specifically, I would like to change the text of label2 based on the value of label1.
I tried with "prepareForSegue", but it seems it's not triggered for embedded view controllers. I tried to isolate the problem in a test project:
Code for main VC:
class MyViewController: UIViewController {
#IBOutlet weak var label1: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
label1.text = "Hello"
}
}
Code for embedded VC:
class EmbeddedVC: UIViewController {
#IBOutlet weak var label2: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
}
Thanks for your help :)
A way to achiŠµve this is to get the child view controller instance in the parent's viewDidLoad. It appears that the parent's viewDidLoad: gets called after the child's viewDidLoad:, which means the label is already created in the child's view.
override func viewDidLoad() {
super.viewDidLoad()
if let childVC = self.childViewControllers.first as? ChildVC {
childVC.someLabel.text = "I'm here. Aye-aye."
}
}
First of all you can't set directly EmbeddedVC's lable2.text In prepareForSegue
because call sequence following below
MainVC's prepareForSeque this time EmbeddedVC's label2 is nil
EmbeddedVC's viewDidLoad called then label2 loaded
MainVC's viewDidLoad called then label1 loaded
so if you assign MainVC's label1.text to EmbeddedVC's label2.text in prepareForSeque
both label1 and label2 are nil so did not work
There are two way to solve this question
First Solution
MainViewController has EmbeddedVC and when MainVC's viewDidLoad called, assign label1.text to embeddedVC.label2.text
class MyViewController: UIViewController {
#IBOutlet weak var label1: UILabel!
var embeddedVC: EmbeddedViewController? = nil
override func viewDidLoad() {
super.viewDidLoad()
label1.text = "Hello"
embeddedVC?.label2.text = label1.text
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let embeddedVC = segue.destination as? EmbeddedViewController {
self.embeddedVC = embeddedVC
}
}
}
class EmbeddedViewController: UIViewController {
#IBOutlet weak var label2: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
}
Second Solution, use protocol and get MainVC's label text when viewWillAppear or viewDidAppear (later viewDidLoad called)
protocol EmbeddedVCDelegate: class {
func labelText() -> String?
}
class MyViewController: UIViewController, EmbeddedVCDelegate {
#IBOutlet weak var label1: UILabel!
// MARK: EmbeddedVCDelegate
func labelText() -> String? {
return label1.text
}
override func viewDidLoad() {
super.viewDidLoad()
label1.text = "Hello"
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let embeddedVC = segue.destination as? EmbeddedViewController {
embeddedVC.delegate = self
}
}
}
class EmbeddedViewController: UIViewController {
#IBOutlet weak var label2: UILabel!
weak var delegate: EmbeddedVCDelegate? = nil
override func viewDidLoad() {
super.viewDidLoad()
}
override viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
label2.text = delegate?.labelText()
}
}
You should try to use prepareForSegue like this:
if segue.identifier == "identifier" {
guard let destinationViewController = segue.destination as? VC2 else { return }
destinationViewController.label2.text = mytext
}
Where the segue identifier you assign in storyboard