What are the methods of integration and dependency injection in software modules?

In iOS, several methods are used for dependency injection and integration:

1. Constructor (initializer) — dependencies are passed through the class initializer parameters.

2. Properties (property injection) — dependencies are set through properties after the object is created.

3. Service locator — the object requests dependencies from a centralized service.

4. Using DI frameworks — for example, Swinject, which automate dependency injection.

Example of injection via initializer:

class NetworkManager {
    // ...
}

class ViewModel {
    let networkManager: NetworkManager

    init(networkManager: NetworkManager) {
        self.networkManager = networkManager
    }
}

let networkManager = NetworkManager()
let viewModel = ViewModel(networkManager: networkManager)

The choice of method depends on the complexity of the project and the requirements for testability and modularity.