面试题与答案

Swift is a programming language developed by Apple for iOS, macOS, watchOS, tvOS, and Linux applications.

Optionals are a type in Swift that represents either a wrapped value or nil, indicating the absence of a value.

'let' is used to declare constants, and 'var' is used to declare variables.

A closure is a self-contained block of functionality that can be passed around and used in your code.

Property observers are used to observe and respond to changes in a property's value, providing a way to execute code before or after the value changes.

The 'static' keyword in Swift is used to define type-level properties and methods that are associated with the type itself, rather than an instance of the type.

Swift Package Manager is a tool for managing the distribution of Swift code as source or binary packages.

'DispatchQueue' is used for managing the execution of tasks serially or concurrently in a multithreaded environment.

'self' is used to refer to the instance of the current type, and it's often required to distinguish between instance variables and parameters with the same name.

'lazy' is used to delay the initialization of a property until it's accessed for the first time.

'frame' represents a view's location and size in its superview's coordinate system, while 'bounds' represents a view's location and size in its own coordinate system.

'throws' is used to indicate that a function can potentially throw an error, and it must be marked with 'try' when called.

The 'UIApplicationDelegate' is a protocol in Swift that defines methods for handling app lifecycle events, such as app launch, termination, and background execution.

A typealias is used to create a named alias for an existing type. It is useful for making code more readable and for simplifying complex type declarations.