CODEWITHSUNDEEP
swiftdeinit
loop masta
loop masta

Reputation: 149

deinit in empty swift Project not called

If i create an new "Single View Application" project with xcode(6.3.2) and add only a deinit function to the ViewController. Run app, close app. Deinit is never called! I tested it with several devices and the simulator.

deinit {
    println("deinit:")
}

Why is that? Is that the standard behaviour? What can i do to make it work?

/* Edit */ After reading the comments i put this code to my Viewcontroller.

import UIKit

class A {
    func test() {
        println("A test")
    }

    deinit {
        println("A deinit")
    }
}

class ViewController: UIViewController {

    var a:A? = A()

    override func viewDidLoad() {
        super.viewDidLoad()
        println("ViewController viewDidLoad")
        a?.test()
    }

    override func viewDidDisappear(animated:Bool) {
        println("ViewController viewDidDisappear")
        a = nil
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        println("ViewController didReceiveMemoryWarning")
    }

    deinit {
        println("ViewController deinit")
        a = nil
    }
}

Now i get 

ViewController viewDidLoad:
A test
ViewController viewDidDisappear:
A deinit

Does this mean that i have to cleanup my objects by hand within the viewDidDisappear call because the view controllers deinit function is not reliable?

Upvotes: 3

Views: 1118

Answers (2)

ingconti
ingconti

Reputation: 11646

As apple states in documentation, App termination is done via SIGKILL that it a lot faster than exiting via sending message.

So no code will be called, neither applicationWillTerminate, for example.

try this code:

//  CustomView.swift
import UIKit

class CustomView: UIView {

    deinit{
        print("Swift CustomView dying...\n")

    }
}

in controller:

var v : CustomView?
        v = CustomView(frame: CGRectZero)

        v = nil

You will we in console:

Swift CustomView dying...

A Sample project is available on request. (write me)

Upvotes: 1

Shamas S
Shamas S

Reputation: 7549

No. In this case the ViewController deinit isn't even being called because ViewController doesn't go out of memory.

A way to test this is to create a new ViewController and replace the current ViewController with it. This should remove your current ViewController out of the memory, hence calling it's deinit method.

Upvotes: 1

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