Swift - 等待委托 function 完成完成处理程序

Question

Suppose I have a function with completion handler and my AppDelegate extends from any notification delegate like this:

var flag = false
class AppDelegate: finishWorkingDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        
    }

    private func updateData(completion: () -> Void) {
        //wait for delegate
        completion()
    }
    
    //delegate function
    func finishWorking(workComplete: Bool) {
        flag = true
    }
}

So my updateData function needs to wait until finishWorking delegate method where called to launch completion.

finishWorking is triggered when a background task did finish at any time.

updateData can be used some where at any moment, like:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    updateData() {
        //do some other work
    }
}

I used a loop for wait until flag changes to true to launch completion

func updateData(completion: () -> Void) {
    while !flag {
        //...
    }
    completion()
}

But this method freezes the app. So, there is a better solution?

PD: I know that I can use the delegate function to do "some other work" but this is a particular case, I made this example code to explain the problem as clear as possible. It needs to be as described.

Answer 1

Whatever the work you do in finishWorking you shouldn't freeze the app, let the app opens the initial vc and show an activity/loading until the heavy work is done then refresh that vc