Hello folks, i want to ask something in my kmm pr...

# multiplatform

[Mobile Dev.]

Hello folks, i want to ask something

in my kmm project i have this line of code

class TestRepo {
    suspend fun test(): Int {
        delay(5000)
        return 10
    }
}

and i'm trying to use test method in my ios application.

class ContentViewModel : ObservableObject {
   
  @Published var training: Training_? = nil
  @Published var k: String? = nil
  @Published var isLoading = false
   
  func fetchData() {
    self.isLoading = true
     
    TestRepo().test { vl, err in
      self.isLoading = false
      self.training = Training_.companion.doInit()
    }
  }
   
}

but when i try app in mobile phone i get these error on the xcode. i fix this issue with using DispatchQueue.main.async, is there any other way to fix this issue without using DispatchQueue ?

[hfhbd]

Use Swift 5.5 and @MainActor to switch back to the main thread

[hfhbd]

What do you mean by: didn't work? What did you try?

[Mobile Dev.]

I add @MainActor to view model like below

@MainActor class ContentViewModel : ObservableObject {
   
  @Published var training: Training_? = nil
  @Published var k: String? = nil
  @Published var isLoading = false
   
  func fetchData() {
    self.isLoading = true
     
    TestRepo().test { vl, err in
      self.isLoading = false
      self.training = Training_.companion.doInit()
    }
  }
   
}

[hfhbd]

Yeah, this won't work. test is a suspending function, and the callback runs on another thread, usually a background thread. So you have to run this callback on the main thread. One option: extract the callback and add the annotation @MainActor on this function only:

class ContentViewModel : ObservableObject {
   
  @Published var training: Training_? = nil
  @Published var k: String? = nil
  @Published var isLoading = false
   
  func fetchData() {
    self.isLoading = true
     
    TestRepo().test { vl, err in
      updateData(vl, err)
    }
  }
  @MainActor
  func updateData(vl, error) {
    self.isLoading = false
      self.training = Training_.companion.doInit()
 }
}