The official answer from Apple is that IBOutlets should be strong. The only case when an IBOutlet should be weak is to avoid a retain cycle. A strong reference cycle can result in memory leaks and app crashes.

Why are IBOutlets weak by default what happens when we make them strong is it even a problem?

Outlets that you create will therefore typically be weak by default, because: Outlets that you create to, for example, subviews of a view controller's view or a window controller's window, are arbitrary references between objects that do not imply ownership.

What is @IBOutlet weak VAR?

@IBOutlet private weak var someLabel: UILabel! Let's break this down by keyword: @IBOutlet makes Interface Builder recognize the outlet. private ensures the outlet isn't accessed outside the current class. weak is used because in most situations the owner of the outlet isn't the same as the owner of the view.

How do you declare a strong IBOutlet in Swift?

As of Xcode 6 beta 2, Swift does not have a way to designate strong outlets. The workaround is to connect the outlet in IB, then remove the @IBOutlet attribute from your source file. Update: This has been added in Xcode 6 beta 3.

What is difference between weak and strong in Swift?

A strong reference means that you want to “own” the object you are referencing with this property/variable. In contrast, with a weak reference you signify that you don't want to have control over the object's lifetime.

Swift for Beginners Part 12 - Strong vs Weak Memory

Why do we use weak in Swift?

The only reason you need to use weak in Swift coding is to avoid strong reference cycles. In short, a strong reference cycle or “retain cycle” is 2 instances holding onto each other. They cannot be removed from memory, which causes a memory leak, which could crash your app, which is a bad user experience.

What is the difference between weak and strong?

The key difference between a strong and a weak or unowned reference is that a strong reference prevents the class instance it points to from being deallocated. ... In other words, weak and unowned references cannot prevent a class instance from being deallocated.

Do IBOutlets need to be weak?

The official answer from Apple is that IBOutlets should be strong. The only case when an IBOutlet should be weak is to avoid a retain cycle. A strong reference cycle can result in memory leaks and app crashes.

What is difference between strong and weak in iOS?

A weak reference is just a pointer to an object that doesn't protect the object from being deallocated by ARC. While strong references increase the retain count of an object by 1, weak references do not. In addition, weak references zero out the pointer to your object when it successfully deallocates.

What is weak reference in Swift?

Weak References. A weak reference is a reference that doesn't keep a strong hold on the instance it refers to, and so doesn't stop ARC from disposing of the referenced instance. This behavior prevents the reference from becoming part of a strong reference cycle.

What is @IBOutlet in Swift?

In the case of @IBOutlet , this is a connection from an Interface Builder user interface component – e.g. a UIButton – to a property in a view controller or other piece of Swift code.

What is an IBOutlet?

IBOutlet is a keyword which is added to a variable declaration. It's an indicator. It does not affect the declaration in any way. However, when the Interface Builder sees it, it will allows a programmer to set this variable through the “outlet” mechanism inside Interface Builder.

What is retain cycle in Swift?

What are retain cycles and memory leaks? A memory leak in iOS is when an amount of allocated space in memory cannot be deallocated due to retain cycles. Since Swift uses Automatic Reference Counting (ARC), a retain cycle occurs when two or more objects hold strong references to each other.

When should you use unowned or weak?

Use a weak reference whenever it is valid for that reference to become nil at some point during its lifetime. Conversely, use an unowned reference when you know that the reference will never be nil once it has been set during initialization.

What is the difference between weak and unowned?

The main difference between weak and unowned is that weak is optional while unowned is non-optional. By declaring it weak you get to handle the case that it might be nil inside the closure at some point. If you try to access an unowned variable that happens to be nil, it will crash the whole program.

What is weak and unowned IOS?

Unowned references are similar to weak references in that they don't keep a strong reference to the instance they are referencing. They serve the same purpose as weak references, that is, they avoid strong reference cycles.

How can you tell if an acid or base is strong or weak?

Strong acids and bases are 100% ionized in aqueous solution. Weak acids and bases are less than 100% ionized in aqueous solution. Salts of weak acids or bases can affect the acidity or basicity of their aqueous solutions.

What is weak strong and unowned in Swift?

Strong vs Weak vs Unowned — Quick Facts. Usually, when a property is being created, the reference is strong unless they are declared weak or unowned . With the property labelled as weak , it will not increment the reference count. An unowned reference falls in between, they are neither strong nor or type optional.

What is strong weak in IOS?

strong: assigns the incoming value to it, it will retain the incoming value and release the existing value of the instance variable. weak: will assign the incoming value to it without retaining it.

What is the difference between strong and weak property attributes?

The main difference is that weak properties turn to nil when the object that is assigned to them gets released. Strong means that as long as this property points to an object, that object will not be automatically released.

What is the difference between strong and weak references in C#?

The difference between a weak and a strong reference to an object is that while the former still allows the garbage collector to reclaim the memory occupied by that object, a strong reference to an object doesn't allow the garbage collector to reclaim the memory occupied by that object if the object is reachable.

What is the difference between IBOutlet and IBAction?

An IBOutlet lets you reference the view from your controller code. An IBAction lets the view call a method in your controller code when the user interacts with the view.

What is IBDesignable and IBInspectable?

IBDesignable is user defined run time. Mean that if any IBDesignable view is rendered on the storyboard, you will find the view and change the value of the IBInspectable property, this will directly reflect on the storyboard without running the app. IBInspectable is run time property, this works as key coding value.