50 iOS Interview Questions And Answers Part 2

Updated on Dec, 2023

Check out Part 1, if you haven’t already :). Let’s get started.

1- Please explain Method Swizzling in Swift

Method Swizzling is a well-known practice in Objective-C and in other languages that support dynamic method dispatching.

Through swizzling, the implementation of a method can be replaced with a different one at runtime, by changing the mapping between a specific #selector(method) and the function that contains its implementation.

To use method swizzling with your Swift classes there are two requirements that you must comply with:

• The class containing the methods to be swizzled must extend NSObject
• The methods you want to swizzle must have the dynamic attribute

2- What is the difference Non-Escaping and Escaping Closures?

The lifecycle of a non-escaping closure is simple:

1. Pass a closure into a function
2. The function runs the closure (or not)
3. The function returns

Escaping closure means, inside the function, you can still run the closure (or not); the extra bit of the closure is stored someplace that will outlive the function. There are…