在另一个的UIViewController初始化中初始化自定义UIViewController

Question

I have these custom UIViewController, LoadingViewController and LoadableViewController and I LoadableViewController needs to present the LoadingViewController upon the startLoading function or dismiss it upon stopLoading function. My attempt is the following but I am not sure how to declare the variable for loadingViewController in the initializer, since it is already defined in the storyboard and will be allocated by the storyboard and I don't want to double allocate it for no reason (meaning add a loadingViewController = LoadingViewController() ) in the init.

import UIKit

class LoadableViewController: UIViewController {

    var loadingViewController: LoadingViewController

    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    override func viewDidAppear(animated: Bool) {
        loadingViewController = storyboard?.instantiateViewControllerWithIdentifier("LoadingiewController") as! LoadingViewController
    }

    func stopLoading() {
        loadingViewController.dismissViewControllerAnimated(true, completion: nil)
    }

    func startLoading() {
        presentViewController(loadingViewController, animated: true, completion: nil)
    }
}

Answer 1

It all looks good to me. There should be no double allocation, as each time the view appears you will overwrite the previous assignment of self.loadingViewController and ARC will garbage collect the old value.

There is no need for self.loadingViewController = LoadingViewController() , as this instance will not know about the interface you created with IBOutlet s on your storyboard. When you use instantiateViewControllerWithIdentifier , an instance of LoadingViewController is created with the UI elements you associated this class with within Interface Builder.