I have two View Controllers. In the first one, let's call it ViewControllerA, I have a Button. In the second view controller, let's call it ViewControllerB, I have a View. The Button in ViewControllerA performs a segue to ViewControllerB. Normally, the View in ViewControllerB has its isHidden property set to true.
How do I make it so when I click the Button in ViewControllerA, the View in ViewControllerB has its isHidden property changed to false?
This is what I have for ViewControllerA
class ViewControllerA: UIViewController {
var buttonPressed : Bool = false
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
#IBAction func theButton(_ sender: Any) {
buttonPressed = true
performSegue(withIdentifier: "goToControllerB", sender: self)
}
}
And this is what I have for ViewControllerB:
class ViewControllerB: UIViewController {
#IBOutlet weak var myView: UIView!
var isButtonPressed : Bool = ViewControllerA().buttonPressed
override func viewDidLoad() {
super.viewDidLoad()
if isButtonPressed == true {
myView.isHidden = false
}
else {
myView.isHidden = true
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
Implement the prepareForSegue method in ViewControllerA like so:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goToControllerB" {
if let destinationVC = segue.destination as? ViewControllerB {
destinationVC.isButtonPressed = false
}
}
}
And in ViewControllerB, change the variable:
var isButtonPressed: Bool?
Just override prepare(for:sender:) in your ViewControllerA like this:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
guard segue.identifier == "goToControllerB", let destination = segue.destination as? ViewControllerB else { return }
destination.isButtonPressed = true
}
Then, inside viewDidLoad() function in your ViewControllerB, set visibility of the view:
myView.isHidden = !isButtonPressed
Related
I have a view controller which has two buttons and an embedded TabBarController.
I want to use the two button instead of the tab bar item. And for some reason cannot make it work.
MainView
import UIKit
class ViewController: UIViewController {
var currentTab = 0
#IBOutlet weak var container: UIView!
#IBAction func item1Button(_ sender: UIButton) {
currentTab = 0
}
#IBAction func item2Button(_ sender: UIButton) {
currentTab = 1
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "toControllers"{
if let vc = segue.destination as? TabsViewController {
vc.selectedIndex = currentTab
}
}
}
}
TabBarController
import UIKit
class TabsViewController: UITabBarController {
override func viewDidLoad() {
super.viewDidLoad()
}
}
I have two items in the storyboard, so item 0 and 1 should be ok.
Maybe it is very simple, cannot figure it out myself.
Thank you!
I figure it out, here is the solution:
Changed the main controller to:
class ViewController: UIViewController {
var currentTab = 1
private var tabViewController: UITabBarController?
#IBOutlet weak var container: UIView!
#IBAction func item1Button(_ sender: UIButton) {
print("click item1")
tabViewController?.selectedIndex = 0
}
#IBAction func item2Button(_ sender: UIButton) {
print("click item2")
tabViewController?.selectedIndex = 1
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "toControllers"{
if let vc = segue.destination as? TabsViewController {
tabViewController = vc
}
}
}
I have two viewcontrollers setup and set the segue connections as well. I'm attempting to pass data from one of the VC's to the other. Using the below code and using the func override works. What i want to do is only have the override func prepare fire off when a button is pressed and when i paste the override func code into a button action, it doesnt work - the label on the first VC doesnt update - it stays to the default value i set.
First ViewController code:
var testLabel1:String = "default"
#IBOutlet weak var testLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
testLabel?.text = testLabel1
// Do any additional setup after loading the view.
}
Second ViewController code:
override func prepare(for segue: UIStoryboardSegue, sender: Any?)
{
if segue.destination is ViewController
{
let vc = segue.destination as? ViewController
vc?.testLabel1 = "Success"
}
}
Button action that ive tried
#IBAction func actionBtn(_ sender: Any) {
func prepare(for segue: UIStoryboardSegue, sender: Any?)
{
if segue.destination is ViewController
{
let vc = segue.destination as? ViewController
vc?.testLabel1 = "Success"
}
}
}
You need to trigger it with performSegue
class FirstVc:UIViewController {
#IBOutlet weak var lbl:UILabel!
#IBAction func goToSecond(_ sender: Any) {
self.performSegue(withIdentifier:"YourSegueName",sender:nil)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "YourSegueName" {
let vc = segue.destination as! SecondVC
vc.testLabel1 = "Success"
}
}
func setData(_ str:String){
self.lbl.text = str
}
}
class SecondVC:UIViewController {
var testLabel1 = ""
weak var delegate:FirstVc?
func goBack() {
self.delegate?.setData("FromSecond")
self.dismiss(animated: true, completion: nil)
}
}
View controller A
class ViewController: UIViewController {
var delegate: server?
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func ok(_ sender: Any) {
delegate?.datum(data: "sd")
performSegue(withIdentifier: "goingB", sender: self)
}
}
View controller B
protocol server {
func datum(data: String)
}
class ViewControllerB: UIViewController, server {
#IBOutlet weak var label: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
func datum(data: String) {
self.label.text = data
print(data)
}
}
I need to pass the data via view controllers but I cannot able to pass however I know we can pass data through protocols, but anyhow I end up with error when try to run the program
If you need to pass data from one view controller to another and you're using segue for presenting new view controller, you can just override prepare(for:sender:), there is no need to using delegates. Here you can get reference for controller which will be presented and you can assign its variable.
So, first create variable in second view controller and declare that if you assign it with new value, it changes text of your label
class ViewControllerB: UIViewController {
#IBOutlet weak var label: UILabel!
var variable: String? {
didSet {
label.text = variable
}
}
}
Now in first view controller override prepare(for:sender:) and if segue is segue which you've performed, downcast destination view controller and assign its variable
class ViewController: UIViewController {
#IBAction func ok(_ sender: Any) {
performSegue(withIdentifier: "goingB", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goingB" {
let destinationVC = segue.destination as! ViewControllerB
destinationVC.variable = "sd"
}
}
}
Anyway, if you want to use your code with delegate, you have to set delegate of first view controller as second view controller which will be presented. For this purpose you can also use prepare(for:sender:) where you can get reference for destination of segue and then you can call your method on delegate
class ViewController: UIViewController {
var delegate: server?
#IBAction func ok(_ sender: Any) {
performSegue(withIdentifier: "goingB", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goingB" {
let destinationVC = segue.destination as! ViewControllerB
delegate = destinationVC
delegate?.datum(data: "sd")
}
}
}
Notes:
Name protocol with big capital letter Server and we are talking about delegates, add delegate word: ServerDelegate
Constrain protocol for just for classes
Make then your delegate variable weak
protocol ServerDelegate: class {
func datum(data: String)
}
...
weak var delegate: ServerDelegate?
The simplest here is to to set the property directly in prepare.
However, if you want to use delegate, you can. Your problem is that you have mixed between A and B.
The way you wrote it, when you call delegate?.datum, delegate is not defined and we can't access datum.
What do you want to do ? Go from A to B, and when in B, update a label in B with data received from A.
Here just to show how to use (but clearly too complex compared with direct assignment).
protocol Server {
func datum() -> String
}
class ViewControllerB: UIViewController {
#IBOutlet weak var label: UILabel!
var delegate: Server?
override func viewDidLoad() {
super.viewDidLoad()
let data = delegate?.datum()
self.label.text = data
}
}
class ViewControllerA: UIViewController, Server {
override func viewDidLoad() {
super.viewDidLoad()
}
var data = "sd"
func datum() -> String {
return data
}
#IBAction func ok(_ sender: Any) {
performSegue(withIdentifier: "goingB", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let destVC = segue.destination as? ViewControllerB {
destVC.delegate = self
}
}
}
I'm absolute newbie in Swift and OSX development, and I'm sorry if my question will be too noob. I want to understand principles of navigation between NSViewControllers.
I have my default ViewController, where are login and password fields and button to login. After click on button, returns token. And now I trying to change "view" to SecondViewController and save somewhere token, I will need it in future. How can I do it? and it possible to do this in function?:
#IBAction func loginButton(_ sender: Any) {
....
}
Thank you!
You need to use segues to perform this action.
First make the segues connections between the ViewControllers using to storyboard editor. After that you need to give the segues an identifier on the storyboard's attributes inspector. Then in your code you can call the new ViewController by the segue like the code below.
With this code you can pass the data using the button:
class ViewController: NSViewController {
var dataToPass: String = "DataToPass"
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func loginButton(_ sender: Any) {
performSegue(withIdentifier: NSStoryboardSegue.Identifier(rawValue: "segueIdentifier"), sender: self)
}
override func prepare(for segue: NSStoryboardSegue, sender: Any?) {
if segue.identifier!.rawValue == "segueIdentifier" {
let destinationViewController = segue.destinationController as! ViewController2
destinationViewController.dataToReceive = dataToPass
}
}
}
class ViewController2: NSViewController {
var dataToReceive: String
override func viewDidLoad() {
super.viewDidLoad()
}
}
And with this code you will use the override viewWillAppear
class ViewController: NSViewController {
var dataToPass: String = "DataToPass"
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewWillAppear() {
performSegue(withIdentifier: NSStoryboardSegue.Identifier(rawValue: "segueIdentifier"), sender: self)
}
override func prepare(for segue: NSStoryboardSegue, sender: Any?) {
if segue.identifier!.rawValue == "segueIdentifier" {
let destinationViewController = segue.destinationController as! ViewController2
destinationViewController.dataToReceive = dataToPass
}
}
}
class ViewController2: NSViewController {
var dataToReceive: String
override func viewDidLoad() {
super.viewDidLoad()
}
}
In both cases you need to assure the data you want to pass to the other view controller is not null.
I want to take a variable nomeLabel in the func goToSecondView and display it on a SecondView
class ViewController: UIViewController {
var nomeLabel:String!
#IBAction func goToSecondView(sender: AnyObject) {
self.performSegueWithIdentifier("goToSecondView", sender: self)
let newButton = sender as UIButton
nomeLabel = newButton.titleLabel!.text
println("nomeLabel \(nomeLabel)")
}
}
how can I do ?
You need to implement prepareForSegue where you have access to the destination view controller. Here is an example on how to do that:
class ViewController: UIViewController {
#IBOutlet var newButton: UIButton!
#IBAction func goToSecondView(sender: AnyObject) {
self.performSegueWithIdentifier("goToSecondView", sender: self)
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "goToSecondView" {
let secondViewController = segue.destinationViewController as SecondViewController
secondViewController.nomeLabel = self.newButton.titleLabel.text
}
}