Knowing where retain cycles are and removing them

by

If you are using Xcode 8 or above, you can use the memory graph thingy to see what object holds a reference to what object.

To see the memory graph, first build and run your app with Xcode. When you want to check whether all the instances you created are discarded properly, go to this tab on the left pane:

enter image description here

Then press the button on the right there:

enter image description here

After that, select the bottom-most option – View Memory Graph Hierarchy:

enter image description here

Now it will show you all the objects that are in memory:

enter image description here

In my case, I have a GameSystem object, 6 ButtonNode objects and a few others. You’ll notice that there is a little ! beside the GameSystem object. That means this object is leaked. Also, GameScene should not be in memory anymore because the current scene is TitleScene. Let’s see what is retaining it by clicking on the instance:

enter image description here

Now you can clearly see that it is retained by a closure!

That is how you use the memory graph to see where you should put weak-references and avoid retain cycles.

More Related Contents:

  1. How to convert Data to hex string in swift
  2. Waiting until the task finishes
  3. round trip Swift number types to/from Data
  4. How do I dispatch_sync, dispatch_async, dispatch_after, etc in Swift 3, Swift 4, and beyond?
  5. What is the difference between a weak reference and an unowned reference?
  6. How to move enemy towards a moving player?
  7. What is the ‘open’ keyword in Swift?
  8. Non-‘@objc’ method does not satisfy optional requirement of ‘@objc’ protocol
  9. How do I detect if an SKSpriteNode has been touched
  10. Accessing code in Swift 3 Error
  11. Shuffle array swift 3
  12. What is a good example to differentiate between fileprivate and private in Swift3
  13. Swift 3 for loop with increment
  14. Express for loops in swift with dynamic range
  15. What happened to the UIView?() constructor in Swift 3.0?
  16. Swap rootViewController with animation?
  17. How does collisionBitMask work? Swift/SpriteKit
  18. Why do Self and self sometimes refer to different types in static functions?
  19. xcode 8 beta 3: Expected ‘,’ joining parts of a multi-clause condition
  20. Add Local Notification in iOS 10 – Swift 3
  21. Xcode 8 / Swift 3 : Simple UIPicker code not working
  22. Make code with Firebase asynchronous
  23. try, try! & try? what’s the difference, and when to use each?
  24. print without newline in swift
  25. How can I disambiguate a type and a module with the same name?
  26. How can I switch views programmatically in a view controller? (Xcode, iPhone)
  27. How to get user home directory path (Users/”user name”) without knowing the username in Swift3
  28. Swift find all occurrences of a substring
  29. Core Data Predicate Filter By Today’s Date
  30. AVAudioEngine downsample issue

Leave a Comment