I'm following this tutorial to integrate Facebook AccountKit with Swift. Almost everything is working but delegate functions are not called and I don't know why this is no happening.
My code:
import UIKit
import AccountKit
class LoginViewController: UIViewController,AKFViewControllerDelegate {
//
var _accountKit: AKFAccountKit?
var _pendingLoginViewController: AKFViewController?
var _authorizationCode: String?
//
override func viewDidLoad() {
super.viewDidLoad()
if _accountKit == nil {
_accountKit = AKFAccountKit(responseType: .accessToken)
}
_pendingLoginViewController = _accountKit!.viewControllerForLoginResume()
_pendingLoginViewController?.delegate = self
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func prepareLoginViewController(loginViewController: AKFViewController) {
loginViewController.delegate = self
}
#IBAction func loginWithPhone(_ sender: UIButton) {
let inputState = NSUUID().uuidString
let vc: AKFViewController = _accountKit!.viewControllerForPhoneLogin(with: nil, state: inputState)
self.prepareLoginViewController(loginViewController: vc)
self.present(vc as! UIViewController, animated: true, completion: nil)
}
private func viewController(viewController: UIViewController!, didCompleteLoginWithAuthorizationCode code: String!, state: String!) {
print("1")
}
private func viewController(viewController: UIViewController!, didCompleteLoginWithAccessToken accessToken: AKFAccessToken!, state: String!) {
print("2")
}
private func viewController(viewController: UIViewController!, didFailWithError error: Error!) {
print("3")
}
private func viewControllerDidCancel(viewController: UIViewController!) {
print("4")
}
}
Swift version: 3.2
I belice is something to do with the swift version (I believe this tutorial is for 2.x) but i had a similar code from an example in Swift 3 and is working. So I don't know what is going wrong.
You don't need to cahnge methods to private.
Change delegate methods to the following:
func viewController(_ viewController: (UIViewController & AKFViewController)!,
didCompleteLoginWith accessToken: AKFAccessToken!, state: String!) {
}
func viewController(_ viewController: (UIViewController & AKFViewController)!, didCompleteLoginWithAuthorizationCode code: String!, state: String!) {
}
func viewController(_ viewController: (UIViewController & AKFViewController)!, didFailWithError error: Error!) {
}
func viewControllerDidCancel(_ viewController: (UIViewController & AKFViewController)!) {
print("canceled")
}
Problem might be that your delegate functions are all private and so the AKFViewController is unable to invoke them. Try making them public and see if you still can't get the callbacks
I'm new to Swift, and trying my hands with UIWebView app that loads default url, with option to perform quick action and load a different url.
Problem is when I request the quick action url, code executes but the new url is not loading. So I'm missing something in the flow somewhere.
Here is the code:
import UIKit
import WebKit
class ViewController: UIViewController, UIWebViewDelegate {
#IBOutlet var webView: UIWebView!
override func loadView() {
super.loadView()
self.webView = UIWebView()
self.view = self.webView!
}
override func viewDidLoad() {
print("view did load")
super.viewDidLoad()
let url = NSURL(string: "google.com")
let req = NSURLRequest(URL:url!)
webView.loadRequest(req)
webView.delegate = self
}
func loadUrl2() {
loadView()
let url = NSURL(string: "example.com")
print(url)
let req = NSURLRequest(URL:url!)
self.webView!.loadRequest(req)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
I was experimenting and added loadView to loadUrl2, as I was getting
fatal error: unexpectedly found nil while unwrapping an Optional value
before that.
Edited to Include loading secondary link:
Here are the changes and files you'll need to make to the App Delegate
enum ShortcutIdentifier: String {
case OpenNewLink
case OpenBetterLink
init?(fullIdentifier: String) {
guard let shortIdentifier = fullIdentifier.componentsSeparatedByString(".").last else {
return nil
}
self.init(rawValue: shortIdentifier)
}
}
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
if let shortcutItem = launchOptions?[UIApplicationLaunchOptionsAnnotationKey] as? UIApplicationShortcutItem {
handleShortcut(shortcutItem)
return false
}
return true
}
func application(application: UIApplication, performActionForShortcutItem shortcutItem: UIApplicationShortcutItem, completionHandler: (Bool) -> Void) {
completionHandler(handleShortcut(shortcutItem))
}
private func handleShortcut(shortcutItem: UIApplicationShortcutItem) -> Bool {
let shortcutType = shortcutItem.type
guard let ShortcutIdentifier = ShortcutIdentifier(fullIdentifier: shortcutType) else {
return false
}
return selectLinkForIdentifier(ShortcutIdentifier)
}
private func selectLinkForIdentifier(identifier: ShortcutIdentifier) -> Bool {
guard let mainView = self.window?.rootViewController as? ViewController else {
return false
}
switch identifier {
case .OpenNewLink:
mainView.urlString = "http://www.bing.com"
mainView.loadWebView(mainView.urlString)
return true
case.OpenBetterLink:
mainView.urlString = "http://www.duckduckgo.com"
mainView.loadWebView(mainView.urlString)
return true
}
}
I also made changes in the MainVC
class ViewController: UIViewController, UIWebViewDelegate {
#IBOutlet var webView: UIWebView!
var urlString: String? = nil
override func viewDidLoad() {
super.viewDidLoad()
setUpWebView()
webView.delegate = self
view.addSubview(webView)
}
func setUpWebView() {
webView = UIWebView()
webView.frame = CGRectMake(0, 0, view.frame.width, view.frame.height)
loadWebView(urlString)
}
func loadWebView(var urlString: String?) {
if urlString == nil {
urlString = "http://www.google.com"
}
let url = NSURL(string: urlString!)
let req = NSURLRequest(URL:url!)
webView.loadRequest(req)
}
}
Be sure to add NSAppTransportSecurity dictionary to your .plist and add NSAllowsArbitraryLoads key set to YES.
I tested it and it should work for you.
I try to use the Spring Framework to play a sound when a button is touched.
import UIKit
class ViewController: UIViewController {
//TODO: max, mia, beide arrays und zufallsgenerator und happy day unten mit klick gleich wave
#IBAction func soundButton(sender: AnyObject) {
let mySound : String! = "refresh.wav"
SoundPlayer.play(mySound)
}
#IBOutlet weak var imageView: SpringImageView!
#IBAction func beideButton(sender: AnyObject) {
imageView.image = UIImage(named: "b1")
imageView.animation = "zoomIn"
imageView.animate()
}
#IBAction func maxButton(sender: AnyObject) {
imageView.image = UIImage(named: "max1")
imageView.animation = "slideLeft"
imageView.animate()
}
#IBAction func miaButton(sender: AnyObject) {
imageView.image = UIImage(named: "mia1")
imageView.animation = "slideRight"
imageView.animate()
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
I get the following error: Cannot invoke 'play' with an argument list of type ('String')
I tried view things like as!, as String, as String!, as? String to unwrap or so but can not figure it out...
Here is the SoundPlayer class (Copyright (c) 2015 James Tang (j#jamztang.com):
import UIKit
import AudioToolbox
public class SoundPlayer: NSObject {
#IBInspectable var filename : String?
#IBInspectable var enabled : Bool = true
private struct Internal {
static var cache = [NSURL:SystemSoundID]()
}
public func playSound(soundFile:String) {
if !enabled {
return
}
if let url = NSBundle.mainBundle().URLForResource(soundFile, withExtension: nil) {
var soundID : SystemSoundID = Internal.cache[url] ?? 0
if soundID == 0 {
AudioServicesCreateSystemSoundID(url, &soundID)
Internal.cache[url] = soundID
}
AudioServicesPlaySystemSound(soundID)
} else {
println("Could not find sound file name `\(soundFile)`")
}
}
#IBAction public func play(sender: AnyObject?) {
if let filename = filename {
self.playSound(filename)
}
}
}
Judging by the code alone (I'm not familiar with Spring), what you need to do is create a SoundPlayer instance and call playSound on it (not play, which uses an internal filename for the sound to play instead of its argument), like this:
#IBAction func soundButton(sender: AnyObject) {
let mySound : String! = "refresh.wav"
let soundPlayer = SoundPlayer()
soundPlayer.playSound(mySound)
}
My speechRecognizer func doesn't seem to be called. I couldn't find anything in the documentation about calling this func.
Any idea what I might be doing wrong? Thanks in advance.
class ViewController: NSViewController, NSSpeechRecognizerDelegate {
let SR:NSSpeechRecognizer = NSSpeechRecognizer()
var commands = ["word","hello"]
override func viewDidLoad() {
super.viewDidLoad()
SR.commands = commands
}
override var representedObject: AnyObject? {
didSet {
// Update the view, if already loaded.
}
}
#IBAction func Listen(sender: AnyObject) {
SR.startListening(); print("listening")
}
#IBAction func Stop(sender: AnyObject) {
SR.stopListening()
}
func speechRecognizer(sender: NSSpeechRecognizer,
didRecognizeCommand command: AnyObject?){
if (command as String == "word")
{
println("case word")
}
else if (command as String == "happy")
{
println("case happy")
}
}
}
Set the NSSpeechRecognizerDelegate to self:
SR.delegate = self
How does one go about making a delegate, i.e. NSUserNotificationCenterDelegate in swift?
Here's a little help on delegates between two view controllers:
Step 1: Make a protocol in the UIViewController that you will be removing/will be sending the data.
protocol FooTwoViewControllerDelegate:class {
func myVCDidFinish(_ controller: FooTwoViewController, text: String)
}
Step2: Declare the delegate in the sending class (i.e. UIViewcontroller)
class FooTwoViewController: UIViewController {
weak var delegate: FooTwoViewControllerDelegate?
[snip...]
}
Step3: Use the delegate in a class method to send the data to the receiving method, which is any method that adopts the protocol.
#IBAction func saveColor(_ sender: UIBarButtonItem) {
delegate?.myVCDidFinish(self, text: colorLabel.text) //assuming the delegate is assigned otherwise error
}
Step 4: Adopt the protocol in the receiving class
class ViewController: UIViewController, FooTwoViewControllerDelegate {
Step 5: Implement the delegate method
func myVCDidFinish(_ controller: FooTwoViewController, text: String) {
colorLabel.text = "The Color is " + text
controller.navigationController.popViewController(animated: true)
}
Step 6: Set the delegate in the prepareForSegue:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "mySegue" {
let vc = segue.destination as! FooTwoViewController
vc.colorString = colorLabel.text
vc.delegate = self
}
}
And that should work. This is of course just code fragments, but should give you the idea. For a long explanation of this code you can go over to my blog entry here:
segues and delegates
If you are interested in what's going on under the hood with a delegate I did write on that here:
under the hood with delegates
Delegates always confused me until I realized that a delegate is just a class that does some work for another class. It's like having someone else there to do all the dirty work for you that you don't want to do yourself.
I wrote a little story to illustrate this. Read it in a Playground if you like.
Once upon a time...
// MARK: Background to the story
// A protocol is like a list of rules that need to be followed.
protocol OlderSiblingDelegate: class {
// The following command (ie, method) must be obeyed by any
// underling (ie, delegate) of the older sibling.
func getYourNiceOlderSiblingAGlassOfWater()
}
// MARK: Characters in the story
class BossyBigBrother {
// I can make whichever little sibling is around at
// the time be my delegate (ie, slave)
weak var delegate: OlderSiblingDelegate?
func tellSomebodyToGetMeSomeWater() {
// The delegate is optional because even though
// I'm thirsty, there might not be anyone nearby
// that I can boss around.
delegate?.getYourNiceOlderSiblingAGlassOfWater()
}
}
// Poor little sisters have to follow (or at least acknowledge)
// their older sibling's rules (ie, protocol)
class PoorLittleSister: OlderSiblingDelegate {
func getYourNiceOlderSiblingAGlassOfWater() {
// Little sis follows the letter of the law (ie, protocol),
// but no one said exactly how she had to respond.
print("Go get it yourself!")
}
}
// MARK: The Story
// Big bro is laying on the couch watching basketball on TV.
let bigBro = BossyBigBrother()
// He has a little sister named Sally.
let sally = PoorLittleSister()
// Sally walks into the room. How convenient! Now big bro
// has someone there to boss around.
bigBro.delegate = sally
// So he tells her to get him some water.
bigBro.tellSomebodyToGetMeSomeWater()
// Unfortunately no one lived happily ever after...
// The end.
In review, there are three key parts to making and using the delegate pattern.
the protocol that defines what the worker needs to do
the boss class that has a delegate variable, which it uses to tell the worker class what to do
the worker class that adopts the protocol and does what is required
Real life
In comparison to our Bossy Big Brother story above, delegates are often used for the following practical applications:
Communication: one class needs to send some information to another class.
Code example 1: sending data from one view controller to another
Code example 2: sending text input from a custom keyboard to a text field
Customization: one class wants to allow another class to customize it.
The great part is that these classes don't need to know anything about each other beforehand except that the delegate class conforms to the required protocol.
I highly recommend reading the following two articles. They helped me understand delegates even better than the documentation did.
What is Delegation? – A Swift Developer’s Guide
How Delegation Works – A Swift Developer’s Guide
One more note
Delegates that reference other classes that they do not own should use the weak keyword to avoid strong reference cycles. See this answer for more details.
It is not that different from obj-c.
First, you have to specify the protocol in your class declaration, like following:
class MyClass: NSUserNotificationCenterDelegate
The implementation will look like following:
// NSUserNotificationCenterDelegate implementation
func userNotificationCenter(center: NSUserNotificationCenter, didDeliverNotification notification: NSUserNotification) {
//implementation
}
func userNotificationCenter(center: NSUserNotificationCenter, didActivateNotification notification: NSUserNotification) {
//implementation
}
func userNotificationCenter(center: NSUserNotificationCenter, shouldPresentNotification notification: NSUserNotification) -> Bool {
//implementation
return true
}
Of course, you have to set the delegate. For example:
NSUserNotificationCenter.defaultUserNotificationCenter().delegate = self;
I got few corrections to post of #MakeAppPie
First at all when you are creating delegate protocol it should conform to Class protocol. Like in example below.
protocol ProtocolDelegate: class {
func myMethod(controller:ViewController, text:String)
}
Second, your delegate should be weak to avoid retain cycle.
class ViewController: UIViewController {
weak var delegate: ProtocolDelegate?
}
Last, you're safe because your protocol is an optional value. That means its "nil" message will be not send to this property. It's similar to conditional statement with respondToselector in objC but here you have everything in one line:
if ([self.delegate respondsToSelector:#selector(myMethod:text:)]) {
[self.delegate myMethod:self text:#"you Text"];
}
Above you have an obj-C example and below you have Swift example of how it looks.
delegate?.myMethod(self, text:"your Text")
Here's a gist I put together. I was wondering the same and this helped improve my understanding. Open this up in an Xcode Playground to see what's going on.
protocol YelpRequestDelegate {
func getYelpData() -> AnyObject
func processYelpData(data: NSData) -> NSData
}
class YelpAPI {
var delegate: YelpRequestDelegate?
func getData() {
println("data being retrieved...")
let data: AnyObject? = delegate?.getYelpData()
}
func processYelpData(data: NSData) {
println("data being processed...")
let data = delegate?.processYelpData(data)
}
}
class Controller: YelpRequestDelegate {
init() {
var yelpAPI = YelpAPI()
yelpAPI.delegate = self
yelpAPI.getData()
}
func getYelpData() -> AnyObject {
println("getYelpData called")
return NSData()
}
func processYelpData(data: NSData) -> NSData {
println("processYelpData called")
return NSData()
}
}
var controller = Controller()
DELEGATES IN SWIFT 2
I am explaining with example of Delegate with two viewControllers.In this case, SecondVC Object is sending data back to first View Controller.
Class with Protocol Declaration
protocol getDataDelegate {
func getDataFromAnotherVC(temp: String)
}
import UIKit
class SecondVC: UIViewController {
var delegateCustom : getDataDelegate?
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func backToMainVC(sender: AnyObject) {
//calling method defined in first View Controller with Object
self.delegateCustom?.getDataFromAnotherVC(temp: "I am sending data from second controller to first view controller.Its my first delegate example. I am done with custom delegates.")
self.navigationController?.popViewControllerAnimated(true)
}
}
In First ViewController Protocol conforming is done here:
class ViewController: UIViewController, getDataDelegate
Protocol method definition in First View Controller(ViewController)
func getDataFromAnotherVC(temp : String)
{
// dataString from SecondVC
lblForData.text = dataString
}
During push the SecondVC from First View Controller (ViewController)
let objectPush = SecondVC()
objectPush.delegateCustom = self
self.navigationController.pushViewController(objectPush, animated: true)
First class:
protocol NetworkServiceDelegate: class {
func didCompleteRequest(result: String)
}
class NetworkService: NSObject {
weak var delegate: NetworkServiceDelegate?
func fetchDataFromURL(url : String) {
delegate?.didCompleteRequest(result: url)
}
}
Second class:
class ViewController: UIViewController, NetworkServiceDelegate {
let network = NetworkService()
override func viewDidLoad() {
super.viewDidLoad()
network.delegate = self
network.fetchDataFromURL(url: "Success!")
}
func didCompleteRequest(result: String) {
print(result)
}
}
Very easy step by step (100% working and tested)
step1: Create method on first view controller
func updateProcessStatus(isCompleted : Bool){
if isCompleted{
self.labelStatus.text = "Process is completed"
}else{
self.labelStatus.text = "Process is in progress"
}
}
step2: Set delegate while push to second view controller
#IBAction func buttonAction(_ sender: Any) {
let secondViewController = self.storyboard?.instantiateViewController(withIdentifier: "secondViewController") as! secondViewController
secondViewController.delegate = self
self.navigationController?.pushViewController(secondViewController, animated: true)
}
step3: set delegate like
class ViewController: UIViewController,ProcessStatusDelegate {
step4: Create protocol
protocol ProcessStatusDelegate:NSObjectProtocol{
func updateProcessStatus(isCompleted : Bool)
}
step5: take a variable
var delegate:ProcessStatusDelegate?
step6: While go back to previous view controller call delegate method so first view controller notify with data
#IBAction func buttonActionBack(_ sender: Any) {
delegate?.updateProcessStatus(isCompleted: true)
self.navigationController?.popViewController(animated: true)
}
#IBAction func buttonProgress(_ sender: Any) {
delegate?.updateProcessStatus(isCompleted: false)
self.navigationController?.popViewController(animated: true)
}
Simple Example:
protocol Work: class {
func doSomething()
}
class Manager {
weak var delegate: Work?
func passAlong() {
delegate?.doSomething()
}
}
class Employee: Work {
func doSomething() {
print("Working on it")
}
}
let manager = Manager()
let developer = Employee()
manager.delegate = developer
manager.passAlong() // PRINTS: Working on it
Delegates are a design pattern that allows one object to send messages to another object when a specific event happens.
Imagine an object A calls an object B to perform an action. Once the action is complete, object A should know that B has completed the task and take necessary action, this can be achieved with the help of delegates!
Here is a tutorial implementing delegates step by step in swift 3
Tutorial Link
Here is real life delegate scenario
Lets make our own UITextField and UITextFieldDelegate
// THE MYSTERIOUS UITEXTFIELD
protocol UITextFieldDelegate {
func textFieldDidChange(_ textField: UITextField) -> Void
}
class UITextField {
var delegate: UITextFieldDelegate?
private var mText: String?
var text: String? {
get {
return mText
}
}
init(text: String) {
}
init() {
}
func setText(_ text: String) {
mText = text
delegate?.textFieldDidChange(self)
}
}
// HERE IS MY APP
class Main {
let textfield = UITextField()
func viewDidLoad() {
print("viewDidLoad")
textfield.delegate = self
textfield.setText("Hello")
}
}
extension Main: UITextFieldDelegate {
func textFieldDidChange(_ textField: UITextField) {
print(textField.text ?? "No string")
}
}
let main = Main()
main.viewDidLoad()
Here Simple Code Example of Delegate:
//MARK: - Protocol ShowResult
protocol ShowResult: AnyObject {
func show(value: Int)
}
//MARK: - MyOperation Class
class MyOperation {
weak var delegate: ShowResult?
func sum(fNumber: Int, sNumber: Int) {
delegate?.show(value: fNumber + sNumber)
}
}
//MARK: - ViewController Class
class ViewController: UIViewController,ShowResult {
var myOperation: MyOperation?
override func viewDidLoad() {
super.viewDidLoad()
loadMyOperation()
myOperation?.delegate = self
myOperation?.sum(fNumber: 100, sNumber: 20)
}
private func loadMyOperation() {
if myOperation == nil {
myOperation = MyOperation()
}
}
func show(value: Int) {
print("value: \(value)")
}
}
The solutions above seemed a little coupled and at the same time avoid reuse the same protocol in other controllers, that's why I've come with the solution that is more strong typed using generic type-erasure.
#noreturn public func notImplemented(){
fatalError("not implemented yet")
}
public protocol DataChangedProtocol: class{
typealias DataType
func onChange(t:DataType)
}
class AbstractDataChangedWrapper<DataType> : DataChangedProtocol{
func onChange(t: DataType) {
notImplemented()
}
}
class AnyDataChangedWrapper<T: DataChangedProtocol> : AbstractDataChangedWrapper<T.DataType>{
var base: T
init(_ base: T ){
self.base = base
}
override func onChange(t: T.DataType) {
base.onChange(t)
}
}
class AnyDataChangedProtocol<DataType> : DataChangedProtocol{
var base: AbstractDataChangedWrapper<DataType>
init<S: DataChangedProtocol where S.DataType == DataType>(_ s: S){
self.base = AnyDataChangedWrapper(s)
}
func onChange(t: DataType) {
base.onChange(t)
}
}
class Source : DataChangedProtocol {
func onChange(data: String) {
print( "got new value \(data)" )
}
}
class Target {
var delegate: AnyDataChangedProtocol<String>?
func reportChange(data:String ){
delegate?.onChange(data)
}
}
var source = Source()
var target = Target()
target.delegate = AnyDataChangedProtocol(source)
target.reportChange("newValue")
output: got new value newValue
In swift 4.0
Create a delegate on class that need to send some data or provide some functionality to other classes
Like
protocol GetGameStatus {
var score: score { get }
func getPlayerDetails()
}
After that in the class that going to confirm to this delegate
class SnakesAndLadders: GetGameStatus {
func getPlayerDetails() {
}
}
In swift 5
I am a beginner, I think this is easiest way to understand in practical scenario
Note:Any improvisations are most appreciated
protocol APIService {
func onSuccessResponse() -> AnyObject
func onFailureResponse() -> AnyObject
}
class APIHelper{
var delegate : APIService?
func postUsersDataAPI() {
//assuming API communication is success
if(success){
let _: AnyObject? = delegate?.onSuccessResponse()
}else if(failure){
let _: AnyObject? = delegate?.onFailureResponse()
}
}
func getAllUsersAPI() {
//assuming API communication is success
if(success){
let _: AnyObject? = delegate?.onSuccessResponse()
}else if(failure){
let _: AnyObject? = delegate?.onFailureResponse()
}
}
}
class ViewController:UIViewController,APIService {
func onSuccessResponse() -> AnyObject {
print("onSuccessResponse") as AnyObject
}
func onFailureResponse() -> AnyObject {
print("onFailureResponse") as AnyObject
}
#IBAction func clickBtnToPostUserData(_ sender: Any) {
let apiHelper = APIHelper()
apiHelper.delegate = self
apiHelper.postAPI()
}