Performance Optimization
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In this demo, you’ll use the Cinematica app from the second lesson, where you’ve already made efficiency enhancements and tackled Network and Data Optimization. Now, it’s time to dive into Thread Optimization. You’ll aim to boost app responsiveness and performance, ultimately delivering a smoother user experience.
Thread Optimization
Multi threading
Building upon what you learned in the previous lesson about fetching upcoming movies, you will now also fetch top rated and popular movies concurrently thanks to multi threading to improve the information available to your app users without compromising performance.
static let topRatedPath = moviePath + "/top_rated"
static let popularPath = moviePath + "/popular"
case fetchTopRated(page: Int)
case fetchPopular(page: Int)
case .fetchTopRated:
return APIsPaths.topRatedPath
case .fetchPopular:
return APIsPaths.popularPath
case .fetchUpcoming(let page), .fetchTopRated(let page), .fetchPopular(let page):
return ["page": "\(page)", "sort_by": "popularity.desc"]
var upcomingMovies: [Movie] = []
var topRatedMovies: [Movie] = []
var popularMovies: [Movie] = []
func fetchUpcomingMovies() async throws {
let moviePaginatedResponse: MoviePaginatedResponse = try await
requestManager.perform(MoviesRequests.fetchUpcoming(page: currentPage))
self.upcomingMovies.append(contentsOf: moviePaginatedResponse.results ?? [])
}
func fetchTopRatedMovies() async throws {
let moviePaginatedResponse: MoviePaginatedResponse = try await
requestManager.perform(MoviesRequests.fetchTopRated(page: currentPage))
self.topRatedMovies.append(contentsOf: moviePaginatedResponse.results ?? [])
}
func fetchPopularMovies() async throws {
let moviePaginatedResponse: MoviePaginatedResponse = try await
requestManager.perform(MoviesRequests.fetchPopular(page: currentPage))
self.popularMovies.append(contentsOf: moviePaginatedResponse.results ?? [])
}
import SwiftUI
struct MovieSectionView: View {
let movies: [Movie]
let title: String
var body: some View {
VStack(alignment: .leading, spacing: 5) {
Text(title)
.font(.title)
.padding(.top, 15)
.padding(.leading, 15)
ScrollView(.horizontal, showsIndicators: false) {
LazyHStack(spacing: 10) {
ForEach(movies, id: \.id) { movie in
MovieCellView(movie: movie)
.frame(width: 150, height: 200)
}
}
}
}
.background(Color(.secondarySystemBackground))
}
}
VStack(spacing: 20) {
MovieSectionView(movies: movieListViewModel.upcomingMovies, title: "Upcoming")
MovieSectionView(movies: movieListViewModel.topRatedMovies, title: "Top Rated")
MovieSectionView(movies: movieListViewModel.popularMovies, title: "Popular")
}
.padding()
if movieListViewModel.errorManager.errorMessage != nil
func fetchAllMovies() async {
isLoading = true
do {
await withThrowingTaskGroup(of: Void.self) { group in
group.addTask {
do {
try await self.fetchUpcomingMovies()
} catch {
self.errorManager.handleError(error)
}
}
group.addTask {
do {
try await self.fetchTopRatedMovies()
} catch {
self.errorManager.handleError(error)
}
}
group.addTask {
do {
try await self.fetchPopularMovies()
} catch {
self.errorManager.handleError(error)
}
}
}
}
isLoading = false
}
Task {
await movieListViewModel.fetchAllMovies()
}
Thread hangs
The code you previously added involves the app retrieving three movie lists in a background thread and subsequently refreshing the UI on the main thread using the view model properties with the help of @Observable. This approach ensures a seamless user interface experience without blocking the UI.
@MainActor // 1
public func perform(_ request: RequestProtocol) async throws -> Data {
sleep(5) // 2
// ...