I have a view controller that is responsible for adding a new object, say a new contact. This view controller (AddContactViewController) has the following UIBarButtonItem on a UINavigationBar, which is starts of disabled until enough information is provided to enable it. Then when this button is pressed a method (doneButtonPressed) is called.
The layout is as follows:
class AddContactViewController: UIViewController {
#IBOutlet weak var doneButton: UIBarButtonItem! {
didSet {
doneButton.isEnabled = false
doneButton.target = self
doneButton.action = #selector(self.doneButtonPressed)
}
}
#objc fileprivate func doneButtonPressed() {
// do some stuff ...
self.dismiss(animated: false, completion: nil)
}
}
As this is quite a common thing to have and there's a lot of boiler plate code, I've been working on a protocol AddingHandler but haven't quite worked out how to have UIBarButtonItem as a weak variable which hooks up to a storboard or if this is even the right way to go.
protocol AddingHandler {
var doneButton: UIBarButtonItem? { get set }
func doneButtonPressed()
}
extension protocol where Self: UIViewController {
func configureDoneButton() {
doneButton.isEnabled = false
doneButton.target = self
doneButton.action = #selector(self.doneButtonPressed)
}
}
Any help or comments in making this work would be much appreciated.
The problem How is best to add a weak UIButton to a protocol which can then be hooked up in a story board where UIViewController implements it? As there is a lot of repetitive code here should I wish to have another AddSomethingViewController I was wondering if there was a neater way of only writing this once (in a protocol with an extension) then calling the protocol in any view controller that is adding something new ...
You can simply configure the doneButton in viewDidLoad()
override func viewDidLoad()
{
super.viewDidLoad()
doneButton.isEnabled = false
doneButton.target = self
doneButton.action = #selector(self.doneButtonPressed)
}
Edit 1:
#objc protocol AddingHandler
{
var doneButton: UIBarButtonItem? { get }
#objc func doneButtonPressed()
}
extension AddingHandler where Self: UIViewController
{
func configureDoneButton()
{
doneButton?.isEnabled = false
doneButton?.target = self
doneButton?.action = #selector(doneButtonPressed)
}
}
class AddContactViewController: UIViewController, AddingHandler
{
#IBOutlet weak var doneButton: UIBarButtonItem!
override func viewDidLoad()
{
super.viewDidLoad()
configureDoneButton()
}
func doneButtonPressed()
{
// do some stuff ...
self.dismiss(animated: false, completion: nil)
}
}
I've used ObjC runtime to resolve the issue. Try implementing it at your end and check if it works for you.
Related
I want to trigger Navigation controller to some other screen when i press the button in UIView class. How can i do this?
//Code for UIView Class in Which Button Iboutlet is created
import UIKit
protocol ButtonDelegate: class {
func buttonTapped()
}
class SlidesVC: UIView {
var delegate: ButtonDelegate?
#IBAction func onClickFinish(_ sender: UIButton) {
delegate?.buttonTapped()
}
#IBOutlet weak var imgProfile: UIImageView!
}
//ViewController Class code in Which Button Protocol will be entertained
class SwipingMenuVC: BaseVC, UIScrollViewDelegate {
var slidesVC = SlidesVC()
override func viewDidLoad() {
super.viewDidLoad()
slidesVC = SlidesVC()
// add as subview, setup constraints etc
slidesVC.delegate = self
}
extension BaseVC: ButtonDelegate {
func buttonTapped() {
self.navigationController?.pushViewController(SettingsVC.settingsVC(),
animated: true)
}
}
A more easy way is to use typealias. You have to write code in 2 places. 1. your viewClass and 2. in your View Controller.
in your SlidesView class add a typealias and define param type if you need otherwise leave it empty.
class SlidesView: UIView {
typealias OnTapInviteContact = () -> Void
var onTapinviteContact: OnTapInviteContact?
#IBAction func buttonWasTapped(_ sender: UIButton) {
if self.onTapinviteContact != nil {
self.onTapinviteContact()
}
}
}
class SwipingMenuVC: BaseVC, UIScrollViewDelegate {
override func viewDidLoad() {
super.viewDidLoad()
let slidesView = SlidesView()
slidesView.onTapinviteContact = { () in
// do whatever you want to do on button tap
}
}
You can use the delegate pattern to tell the containing ViewController that the button was pressed and let it handle whatever is needed to do next, The view doesn't really need to know what happens.
A basic example:
protocol ButtonDelegate: class {
func buttonTapped()
}
class SomeView: UIView {
var delegate: ButtonDelegate?
#IBAction func buttonWasTapped(_ sender: UIButton) {
delegate?.buttonTapped()
}
}
class ViewController: UIViewController {
var someView: SomeView
override func viewDidLoad() {
someView = SomeView()
// add as subview, setup constraints etc
someView.delegate = self
}
}
extension ViewController: ButtonDelegate {
func buttonTapped() {
self.showSomeOtherViewController()
// or
let vc = NewViewController()
present(vc, animated: true)
}
}
I have an onboarding user flow:
Name -> Age -> Gender
Each of the screens shares the same structure:
Question (top)
Input (middle)
Continue (bottom)
I have a class OnboardingHelper.swift that creates a class to set the question box and continue button:
class UserOnboardingHelper{
var text: String
var questionbox: UIView
var viewController: UIViewController
var continueButton: UIButton
init(text: String, questionbox: UIView, viewController: UIViewController, continueButton: UIButton){
self.text = text
self.questionbox = questionbox
self.viewController = viewController
self.continueButton = continueButton
}
func setQuestionBox(){
//sets question box
}
func setContinueButton(){
//sets continue button
enableContinueButton()
addContinueButtonPath()
}
func enableContinueButton(){
//enables continue button
}
func disableContinueButton(){
//disables continue button
}
func addContinueButtonPath(){
//sets path of continue button based on which view
}
}
In each of the onboarding ViewControllers I am setting the class in ViewDidLoad():
class NamePageViewController: UIViewController, UITextFieldDelagate {
#IBOutlet weak var questionbox: UIView!
#IBOutlet weak var continueButton: UIButton!
#IBOutlet weak var inputLabel: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
let namePageSettings = UserOnboardingHelper(text: "What is your name", questionbox: questionbox, viewController: self, continueButton: continueButton)
namePageSettings.setQuestionBox()
namePageSettings.setContinueButton()
inputLabel.delegate = self
if nameIsFilled {
namePageSettings.enableContinueButton()
} else{
namePageSettings.disableContinueButton()
}
}
}
The issue is that in the ViewController I textFieldDidEndEditing() function which needs to call the namePageSettings class from viewDidLoad()
func textFieldDidEndEditing(_ textField: UITextField){
if (textField.text?.empty)!{
//I want to call disableContinueButton() from UserOnboardingHelper
} else {
//I want to enable enableContinueButton() from UserOnboardingHelper
}
}
Trying to understand if:
The overall approach is correct and if not, what's the best way
If the above approach is in the right direction, how should disableContinueButton() and enableContinueButton() be called?
Thanks in advance! Sorry if the approach is really dumb - I'm still trying to wrap my head around classes.
You can have the view controller have a weak reference to the onboarding helper, so you can still call helper methods without creating a retain cycle.
In NamePageViewController, add a property:
weak var userOnboardingHelper: UserOnboardingHelper?
Then, in UserOnboardingHelper's initializer, add:
self.viewController.userOnboardingHelper = self
You can now call the onboarding helper's methods in the view controller:
userOnboardingHelper.disableContinueButton()
userOnboardingHelper.enableContinueButton()
I have a viewController with another containerView insider set up to appear temporarily (added programmatically). The containerView is a sort of operation bar, which allows you to change values of the viewController. The protocol called from an IBAction of a button however, does not call the protocol set up inside the viewController class.
Here is the code from both classes:
class viewController: UIViewController, updateListDelegate {
let dataSource = containerView()
override func viewDidLoad() {
super.viewDidLoad()
dataSource.delegate = self
}
func updateList(sender: containerView) {
print("is called") //is not printed
}
}
The code from the containerView:
protocol updateListDelegate {
func updateList(containerView)
}
class containerView: UIViewController {
var delegate: updateListDelegate?
#IBAction func AddSong(_ sender: UIButton) {
self.delegate?.updateList(sender: self)
}
}
If this method is only to be called from one object, then, in my opinion, I would not define a protocol. If multiple objects are to call this method, then I would define a protocol. This is typically how you would call a method backwards, using a basic delegate.
class ViewController: UIViewController {
let container = ContainerView()
override func viewDidLoad() {
super.viewDidLoad()
container.viewControllerDelegate = self
// push to this instance of container at some point
}
func doSomething() {
print("great success")
}
}
class ContainerView: UIViewController {
weak var viewControllerDelegate: ViewController?
#objc func someAction() {
if let viewControllerDelegate = viewControllerDelegate {
viewControllerDelegate.doSomething()
}
}
}
// prints "great success" when someAction() called
One of the most common mistakes people make is not keeping track of instances. For delegates to work, you must be sure you are using the specific instances that you've instantiated and assigned those delegates to.
I'm trying to access a var which located in another class(ViewController), but I cannot access answeredCorrectly variable in LastView class. How can I access it and when I call answeredCorrectly like that(marked with 1) is it going to use the default instance of ViewController?
I tried that(LastView.swift)
import Foundation
import UIKit
class LastView: ViewController {
#IBOutlet weak var numberLabel: UILabel!
func assignLabelToCount(){
numberLabel.text = "\(answeredCorrectly)"
}
}
Whole View Controller
import UIKit
class ViewController: UIViewController, UITextFieldDelegate {
#IBOutlet weak var questionLabel: UILabel!
#IBOutlet weak var answerBox: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
answerBox.addTarget(self, action: "textFieldDidChange:", forControlEvents: UIControlEvents.EditingChanged)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
var questionShowing = ""
var answerForControl = 0
#IBAction func newButton() {
var question = getQuestion()
questionShowing = question.0
answerForControl = question.1
questionLabel.text = questionShowing
var timer = NSTimer.scheduledTimerWithTimeInterval(2, target: self, selector: Selector("endGame"), userInfo: nil, repeats: false)
print()
}
func print(){
println("\(questionShowing) >>>>>> \(answerForControl)")
}
var answeredCorrectly = 0
func textFieldDidChange(textField: UITextField) {
var answerInInt = String(stringInterpolationSegment: answerForControl)
var answer: String? = String(answerInInt)
if answerBox.text == answer {
newButton()
answeredCorrectly++
answerBox.text = ""
} else {
}
}
func endGame(){
println("Count of correct answers: \(answeredCorrectly)")
answeredCorrectly = 0
LastView().assignLabelToCount()
performSegueWithIdentifier("toEnd", sender: nil)
}
func getQuestion() -> (String, Int){...}
}
There are a couple of things you could do, if you want to utilize inheritance, go ahead and try this kind of structure:
class ViewController : UIViewController {
//the var you want to access
var answeredCorrectly: Int = ViewController().answeredCorrectly
//your other code
//....
}
then, inherit the class, since your class LastView inherits ViewController, any class that inherits ViewController will now have access to UIViewController.
Note
If you haven't changed the subclass of your ViewController, it should be UIViewController by default.
let's inherit the class for your LastView class:
class LastView : ViewController {
//now your LastView class inherits from ViewController, which also inherits
//from UIViewController, it's like a big chain of classes
#IBOutlet weak var numberLabel: UILabel!
func assignLabelToCount() {
numberLabel.text = "\(answeredCorrectly)"
}
}
The function just simply assigns your variable answeredCorrectly, which is located in ViewController.
declare variable numberLabel as public
You need to create instance of that class to access the variable.
Ex:
var lastViewInstance: LastView = LastView() // Declare in the class in which you want to access the variable
lastViewInstance.numberLabel.text = "Access from Another class"
This is how you can access any variable or outlet!
You can store your object into disk by using NSUserDefaults and you can use it this way:
Store your object to NSUserDefaults:
NSUserDefaults.standardUserDefaults().setObject("YouObjectValue", forKey: "YourKey")
After that you can access it anywhere into your project this way:
let yourVar: AnyObject? = NSUserDefaults.standardUserDefaults().objectForKey("YourKey")
Hope it will help you.
I have a View. In this view, I have a Container View. And in the ContainerView I have a button.
When I am touching the button of the ContainerView, I want the ContainerView become hidden.
I want to do something like that :
class ContainerView: UIViewController {
#IBAction func closeContainerViewButton(sender: AnyObject) {
//I try this : self.hidden = false
//or this : self.setVisibility(self.INVISIBLE)
}
}
Any idea how do it?
There are serval ways but here is the easiest one, not prettiest though. You should really use delegates but this is a hacky way to get started. Just create a global variable of the class that holds the container (startController in this case). Then call it from your other view controller (MyViewInsideContainer) and tell it to hide the view you´re in. I have not run this code but it should work.
var startController = StartController()
class StartController:UIViewController {
#IBOutlet var myViewInsideContainerView: UIView
....
override func viewDidLoad() {
super.viewDidLoad()
startController = self
}
func hideContainerView(){
self.myContainerView.hidden = true
}
}
class MyViewInsideContainer:UIViewController {
...
#IBAction func hideThisView(sender: AnyObject) {
startController.hideContainerView()
}
}
i think a cleaner solution is to use delegation:
in the ParentViewController
class ParentViewController: UIViewController ,ContainerDelegateProtocol
{
#IBOutlet weak var containerView: UIView!
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
//check here for the right segue by name
(segue.destinationViewController as ContainerViewController).delegate = self;
}
func Close() {
containerView.hidden = true;
}
in the ContainerViewController
protocol ContainerDelegateProtocol
{
func Close()
}
class ContainerViewController: UIViewController {
var delegate:AddTaskDelegateProtocol?
#IBAction func Close(sender: AnyObject) { //connect this to the button
delegate?.CloseThisShit()
}