iOS Design Patterns
Singleton, Factory, Builder, Observer, Coordinator, Repository, Dependency Injection, SOLID
1Which pattern guarantees only one instance of a class throughout the application?
Which pattern guarantees only one instance of a class throughout the application?
回答
The Singleton pattern restricts instantiation to a single global instance. In iOS, it enables centralized access to shared resources like configurations or managers. However, Singletons reduce testability by creating hard-to-mock global dependencies.
2Which pattern abstracts object creation without exposing the exact instantiation logic?
Which pattern abstracts object creation without exposing the exact instantiation logic?
回答
The Factory pattern encapsulates object creation in a dedicated method or class. This allows modifying creation logic without affecting client code. In iOS, factory methods simplify managing complex dependencies and facilitate testing through easy substitutions.
3Which pattern constructs complex objects step-by-step while separating construction from representation?
Which pattern constructs complex objects step-by-step while separating construction from representation?
回答
The Builder pattern enables creating objects with many optional parameters without overloading constructors. In iOS, it improves code clarity and maintenance. Unlike Factory that returns immediately, Builder allows progressive and fluid configuration.
Which pattern defines a one-to-many dependency where observers are automatically notified of changes?
What is the main use of a Factory to create objects with conditional logic?
+21 面接問題