Questions tagged [strong-reference-cycle]
8 questions
48
votes
3 answers
Swift delegation - when to use weak pointer on delegate
Can someone explain when and when not to use a 'weak' assignment to a delegate pointer in Swift, and why?
My understanding is that if you use a protocol that is not defined as a class you cannot, nor want to, assign your delegate pointer to…
nwales
- 3,521
- 2
- 25
- 47
7
votes
0 answers
How can I find all closures?
We've totally forgotten to capture self and its properties when referencing it within a closure. (Note: the compiler didn't warn us.) Now our application is full with strong reference cycles. To fix them, we have to add the capture list to each…
Display Name
- 4,502
- 2
- 47
- 63
2
votes
2 answers
Is a strong reference cycle created in this simple case of using URLSession?
I'm a little confused about how strong references are created and when reference cycles occur. Here's a simple example:
class Model {
var foo: Data?
func makeRequest(url: URL) {
let task = URLSession.shared.dataTask(with: url) {…
gsv37
- 23
- 3
2
votes
0 answers
Swift: Weakly reference function as closure?
In Swift, I'm currently facing the issue where I need to often wrap functions in closures in order to prevent strong reference cycles when passing on a class's function as a closure parameter. For example, in the scenario below:
class A {
var…
ImJustACowLol
- 826
- 2
- 9
- 27
1
vote
1 answer
Will referencing an array of instances of a class in a class create a strong reference cycle?
I have the following class:
class Circle: CustomStringConvertible, Hashable, Equatable
{
...
var bonus5Circles = [Circle]()
...
}
Now, in most cases the bonus5Circles array will be empty, but in some cases it will contain some subset of…
Mike Pandolfini
- 532
- 4
- 17
1
vote
2 answers
Swift, why don't class methods need closure lists
If functions are essentially closures. Why don't methods of a class need closure lists when referencing self or another instance property within the closure.
Is there a [unowned self] behind the scenes? For example:
class MyClass{
func…
webbyweb
- 385
- 2
- 11
0
votes
1 answer
Swift strong reference cycles with arrays
If I have a class A which has a variable x which is an array of class B, and class B which always has a variable y parent of class A, how do I set up to avoid strong reference cycles. I get an error if I put
class A {
weak var x = [B]
...}
(even…
domc
- 147
- 1
- 12
-1
votes
1 answer
Objective-C retain cycle between 2 objects
Here is the code:
TestA *ta = [[TestA alloc] init];
TestB *tb = [[TestB alloc] init];
ta.b = tb;
tb.a = ta;
I tried to set ta = nil or tb = nil. It didn't work but ta.b = nil worked. Why?
allentang
- 13
- 1