I got error : does not conform to protocol CLWeeklyCalendarViewDelegate,
Please give any solution for problem, I don't know what are the missing methods in my class.
You have to confirm protocol to the delegate by adding CLWeeklyCalendarViewDelegate> ahead to interface
In Objective C
#interface MyViewController: UIViewController <CLWeeklyCalendarViewDelegate>
In Swift
class MyViewController: UIViewController, CLWeeklyCalendarViewDelegate{
}
First you need to confirm the protocol by writing
calendarWeekView.delegate = self
Also define your protocol at top while defining the class as below
class YourSwiftClass: UIViewController, CLWeeklyCalendarViewDelegate
Implement the delegate method as below
func dailyCalendarViewDidSelect(_ date: Date!) {
}
Related
I have a protocol that I want to add a class constraint to, well I want it constrained to one of two classes actually, either a UIView or a UIViewController, but I can't get it to work. I've tried:
protocol MyProtocol where Self: UIView | UIViewController
protocol MyProtocol where Self: UIView, UIViewController
protocol MyProtocol: UIView, UIViewController
But I can't get it to work. Is this possible or am I just wasting my time?
UIView and UIViewController are class and both Objective-C and Swift don't support multiple inheritance from a class.
So, it will give you multiple inheritance error:
protocol MyProtocol: UIView, UIViewController
If you see something like this:
class ViewController: UIViewController, PKCanvasViewDelegate, PKToolPickerObserver
This class is inheriting one class and conforming two protocols. The point is Swift only support single inheritance from a class.
Suppose there are two class one in swift and other is in objective-c class in same project.
In swift class i declared delegate and i want to set that delegate in objective c class.
I have done this following way ...
import UIKit
#objc public protocol SwiftLoginVCDelegate: class {
}
#objc public class SwiftLoginViewController: UIViewController {
#IBOutlet var txtUserName: UITextField!
#IBOutlet var txtPassword: UITextField!
#IBOutlet var btnLogin: UIButton!
var delegate: SwiftLoginVCDelegate?
override public func viewDidLoad() {
super.viewDidLoad()
self.txtPassword.text = "XYZ"
self.txtPassword.text = "123"
self.btnLogin.backgroundColor = UIColor.blue
}
#objc public func testObjective(){
print("Swift class is integrated in objective c project")
}
the objective c class is
#import "Mediator.h"
#class SwiftLoginViewController;
#protocol SwiftLoginVCDelegate;
#interface LoginMediator : Mediator
#end
Implementation Class is
#import "xyz-Swift.h"
#class SwiftLoginViewController;
#implementation LoginMediator
-(void)onRegister
{
// line 1: [(XYZController*)self.viewComponent setDelegate:self];
line 2 : [(SwiftLoginViewController*)self.viewComponent setDelegate:self];
[objectVC testObjective];
}
If u check the onRegister Method , In line No 1 delegate is set using objective c, which is commented now , but i want to set same delegate in swift 4 , line no 2, when I try to set delegate in swift 4 I am getting following error
No visible #interface for 'SwiftLoginViewController' declares the
selector 'setdelegate';
Note :
One more that i am able to access all the var and function defined in
swift class to objective c Class. I am not able to set the
Delegate in objective c Class which is declared in swift Class.
Can any one has any idea what i am doing wrong in above code ? All inputs are appreciated.
Okay so I've made a sample project in Objective-C and then installed my Swift framework called GPKit, once I made it working, I realized you're not using Cocoapod. So I made a sample Swift class and then used it in my Objective-C class.
First, you need to learn how to properly use a Swift file/class inside your Objective-C class, learn from here: Can't use Swift classes inside Objective-C
And then once you get it working, confirming to a Swift delegate and implementing the functions in that delegate will be easy.
What I can see in your implementation is that you're making a new class and protocol.
#class SwiftLoginViewController;
#protocol SwiftLoginVCDelegate;
Here's the sample code that I made just for this question:
ViewController.m
#import "TestObjcUsingGPKit-Swift.h"
#import "ViewController.h"
#interface ViewController () <CuteDelegate>
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
CuteClass *newCutie = [[CuteClass alloc] init];
newCutie.delegate = self;
}
- (void)myCuteFunc {
// --- the delegate function
}
#end
CuteClass.swift
import UIKit
#objc public protocol CuteDelegate: NSObjectProtocol {
#objc func myCuteFunc()
}
public class CuteClass: NSObject {
weak var delegate: CuteDelegate?
}
The full sample project on GitHub for you: https://github.com/glennposadas/UsingSwift-In-ObjectiveC
I had the exact same issue as you. I noticed that the generated -Swift.h file did not expose the weak delegate member in my Swift file to the objective-c runtime. You can verify this by doing a command+click on your #import -Swift.h file and search for you Swift class name to see what methods/members are exposed.
To finally fix the issue, I ended up adding the #objc tag to my delegate. In your case it would be:
#objc weak var delegate: SwiftLoginVCDelegate?
After I did that, I observed the -Swift.h file again, and lo and behold my delegate was exposed and I'm able to use it in my objective c file as expected.
Hope this helps.
#Gleen response is fine but you must add #objc to var delegate too
weak var delegate: CuteDelegate?
The issue is coming from using setdelegate instead of setDelegate ( see the lowercase delegate).
Try:
[(SwiftLoginViewController*)self.viewComponent setDelegate:self];
// or
((SwiftLoginViewController*)self.viewComponent).delegate = self;
I was stuck on this until I found a different problem: I had #objcMembers on the Swift class definition, but the protocol definition sits outside of the class definition and needs its own #objc annotation.
#property (strong, nonatomic) UIViewController<UITableViewDelegate> *thing;
I want to implement a property like in this Objective-C code in Swift. So here is what I've tried:
class AClass<T: UIViewController where T: UITableViewDelegate>: UIViewController {
var thing: T!
}
This compiles. My problem comes when I add properties from the storyboard. The #IBOutlet tag generates an compiler error.
class AClass<T: UIViewController where T: UITableViewDelegate>: UIViewController {
#IBOutlet weak var anotherThing: UILabel! // error
var thing: T!
}
The error:
Variable in a generic class cannot be represented in Objective-C
Am I implementing this right? What can I do to fix or get around this error?
EDIT:
Swift 4 finally has a solution for this problem. See my updated answer.
Update for Swift 4
Swift 4 has added support for representing a type as a class that conforms to a protocol. The syntax is Class & Protocol. Here is some example code using this concept from "What's New in Swift" (session 402 from WWDC 2017):
protocol Shakeable {
func shake()
}
extension UIButton: Shakeable { /* ... */ }
extension UISlider: Shakeable { /* ... */ }
// Example function to generically shake some control elements
func shakeEm(controls: [UIControl & Shakeable]) {
for control in controls where control.isEnabled {
control.shake()
}
}
As of Swift 3, this method causes problems because you can't pass in the correct types. If you try to pass in [UIControl], it doesn't have the shake method. If you try to pass in [UIButton], then the code compiles, but you can't pass in any UISliders. If you pass in [Shakeable], then you can't check control.state, because Shakeable doesn't have that. Swift 4 finally addressed the topic.
Old Answer
I am getting around this problem for the time being with the following code:
// This class is used to replace the UIViewController<UITableViewDelegate>
// declaration in Objective-C
class ConformingClass: UIViewController, UITableViewDelegate {}
class AClass: UIViewController {
#IBOutlet weak var anotherThing: UILabel!
var thing: ConformingClass!
}
This seems hackish to me. If any of the delegate methods were required, then I would have to implement those methods in ConformingClass (which I do NOT want to do) and override them in a subclass.
I have posted this answer in case anyone else comes across this problem and my solution helps them, but I am not happy with the solution. If anyone posts a better solution, I will accept their answer.
It's not the ideal solution, but you can use a generic function instead of a generic class, like this:
class AClass: UIViewController {
#IBOutlet weak var anotherThing: UILabel!
private var thing: UIViewController?
func setThing<T: UIViewController where T: UITableViewDelegate>(delegate: T) {
thing = delegate
}
}
I came across the same issue, and also tried the generic approach. Eventually the generic approach broke the entire design.
After re-thinking about this issue, I found that a protocol which cannot be used to fully specify a type (in other words, must come with additional type information such as a class type) is unlikely to be a complete one. Moreover, although the Objc style of declaring ClassType<ProtocolType> comes handy, it disregards the benefit of abstraction provided by protocol because such protocol does not really raise the abstraction level. Further, if such declaration appears at multiple places, it has to be duplicated. Even worse, if multiple declarations of such type are interrelated (possibly a single object will be passed around them ), the programme becomes fragile and hard to maintain because later if the declaration at one place needs to be changed, all the related declarations have to be changed as well.
Solution
If the use case of a property involves both a protocol (say ProtocolX) and some aspects of a class (say ClassX), the following approach could be taken into account:
Declare an additional protocol that inherits from ProtocolX with the added method/property requirements which ClassX automatically satisfy. Like the example below, a method and a property are the additional requirements, both of which UIViewController automatically satisfy.
protocol CustomTableViewDelegate: UITableViewDelegate {
var navigationController: UINavigationController? { get }
func performSegueWithIdentifier(identifier: String, sender: AnyObject?)
}
Declare an additional protocol that inherits from ProtocolX with an additional read-only property of the type ClassX. Not only does this approach allow the use of ClassX in its entirety, but also exhibits the flexibility of not requiring an implementation to subclass ClassX. For example:
protocol CustomTableViewDelegate: UITableViewDelegate {
var viewController: UIViewController { get }
}
// Implementation A
class CustomViewController: UIViewController, UITableViewDelegate {
var viewController: UIViewController { return self }
... // Other important implementation
}
// Implementation B
class CustomClass: UITableViewDelegate {
private var _aViewControllerRef: UIViewController // Could come from anywhere e.g. initializer
var viewController: UIViewController { return _aViewControllerRef }
... // UITableViewDelegate methods implementation
}
PS. The snippet above are for demonstration only, mixing UIViewController and UITableViewDelegate together is not recommended.
Edit for Swift 2+: Thanks for #Shaps's comment, the following could be added to save having to implement the desired property everywhere.
extension CustomTableViewDelegate where Self: UIViewController {
var viewController: UIViewController { return self }
}
you can declare a delegate in Swift like this:
weak var delegate : UITableViewDelegate?
It will work with even hybrid(Objective-c and swift) project. Delegate should be optional & weak because its availability is not guaranteed and weak does not create retain cycle.
You are getting that error because there are no generics in Objective-C and it will not allow you to add #IBOutlet property.
Edit: 1. Forcing a type on delegate
To force that delegate is always a UIViewController you can implement the custom setter and throw exception when its not a UIViewController.
weak var _delegate : UITableViewDelegate? //stored property
var delegate : UITableViewDelegate? {
set {
if newValue! is UIViewController {
_delegate = newValue
} else {
NSException(name: "Inavlid delegate type", reason: "Delegate must be a UIViewController", userInfo: nil).raise()
}
}
get {
return _delegate
}
}
In one of my Objective-C clases, I have a property of type UIViewController<UIProfileListHeaderDelegate>, how would I represent this in Swift? I need to access properties and methods from both UIViewController and UIProfileListHeaderDelegate.
Thanks!
The swift way to handle this is to define a protocol that includes the relevant methods from UIViewController and have your UIProfileListHeaderDelegate inherit from that.
Define a protocol with the methods you care about:
protocol ViewControllerSubset {
var view:UIView!
}
Declare that UIViewController implements the protocol, don't need to actually implement anything because it's already there
extension UIViewController : ViewControllerSubset {}
Inherit your protocol from that
protocol UIProfileListHeaderDelegate : ViewControllerSubset
And away you go.
If you don't want to change the hierarchy of your protocol (or can't because it's a system protocol) you can define a protocol that contains both protocols)
protocol EquatableAndComparable : Equatable, Comparable { }
I am trying to use GameCenter to show the leaderboards for the high scores in my game. I have been trying to use some code to implement GameCenter but it all fails.
I'm told to set gameCenterDelegate before the GameCenter view controller is shown.
I've been told to do it like this:
var gcViewController: GKGameCenterViewController = GKGameCenterViewController()
gcViewController.gameCenterDelegate = self
but this gives me the following error:
Type 'MenuViewController' does not conform to protocol 'GKGameCenterControllerDelegate'
I tried changing this:
class MenuViewController: UIViewController {
to:
class MenuViewController: GKGameCenterViewControllerDelegate {
but this gives me loads of errors, the first of which being on this line, reading:
Use of undeclared type 'GKGameCenterViewControllerDelegate'
I have been trying to get this to work for about a fortnight, and there seems to be no solution anywhere. Can someone please help me???
Your MenuViewController needs to be both a subclass of UIViewController and to declare that it implements the delegate. If you've imported GameKit correctly, then:
class MenuViewController: UIViewController, GKGameCenterControllerDelegate {
...
}
should work. I agree that the syntax is a bit confusing, with no demarkation between the superclass and the implemented protocols.
Edit: Whoops, simple error. The delegate is actually GKGameCenterControllerDelegate not GKGameCenterViewControllerDelegate. Declare that you implement it as above, then actually implement the methods.