Weak' must not be applied to non-class-bound consider adding a protocol conformance that has a class bound

Asked Jun 28 '18 at 12:27

Active Jun 28 '18 at 12:27

Viewed 2.7k times

I have a made a protocol in my VC in which i'm getting the location placemark from one my my swift file class. In my swift class i have declare the protocol like this,

 weak var delegate: HandleMapSearch?

But the xcode is showing me error 'weak' must not be applied to non-class-bound 'HandleMapSearch'; consider adding a protocol conformance that has a class bound . It was working fine before but now when i run the app it shows this error. What is this for and how can i remove this error? This is how i have created protocol in my VC class.

protocol HandleMapSearch {
func dropPinZoomIn(placemark:MKPlacemark)
}

asked Jun 28 '18 at 12:27

raheem

1

I have searched this but i couldn't get the answer. @Martin R – raheem Jun 28 '18 at 12:30
88

`protocol HandleMapSearch: class { ... }` – Martin R Jun 28 '18 at 12:31
i didn't get what u have written can u plz elaborate? @MartinR – raheem Jun 28 '18 at 12:31
8

**protocol HandleMapSearch : class { func dropPinZoomIn(placemark:MKPlacemark) }** – Shehata Gamal Jun 28 '18 at 12:32
still it is showing same error. @Sh_Khan – raheem Jun 28 '18 at 12:37
In this line protocol HandleMapSearch : class where class is written i have to replace it with my VC class name? @Sh_Khan – raheem Jun 28 '18 at 12:39
no , copy it as it is – Shehata Gamal Jun 28 '18 at 12:39
i have written that but my error remains the same. @Sh_Khan – raheem Jun 28 '18 at 12:42
ok edit your code – Shehata Gamal Jun 28 '18 at 12:44
6

@ raheem: Conform your protocol with class, because we need weak to break the strong reference cycle and it happens only with class. – Rubiya Faniband May 14 '19 at 16:20
11

protocol HandleMapSearch: AnyObject – Mohamed Aziz Bessrour Jul 04 '19 at 14:50
@MartinR, this is not a duplicate. It is a separate error message. – Alex Zavatone Oct 11 '19 at 18:25
1

Add `: class` after `protocol HandleMapSearch` and before { . @MartinR could have been a little more helpful in his comment by instead posting an answer and not have closed this as a duplicate. This is a commonly encountered problem. The fix should look like this: `protocol HandleMapSearch: class {`. – Alex Zavatone Oct 11 '19 at 18:34
2

As @MohamedAzizBessrour mentioned, use `protocol HandleMapSearch: AnyObject { ... }` if you use Swift 4 or later. https://useyourloaf.com/blog/class-only-protocols-in-swift-4/ – Muhammad Yusuf May 13 '20 at 09:26
1

You need to conform AnyObject in your protocol like this: `protocol HandleMapSearch: AnyObject { func dropPinZoomIn(placemark:MKPlacemark) }` as @MohamedAzizBessrour mentioned. The reason is that by conforming AnyObject, you are making sure that the delegate that adopts this AnyObject, must be a class. As a result, you may now declare your delegate variable as weak. – Nilay Dagdemir Feb 02 '21 at 21:26

Weak' must not be applied to non-class-bound consider adding a protocol conformance that has a class bound

0 Answers0