Building a Pixabay Photo Explorer App with SwiftUI and Alamofire

In this tutorial, we’ll create an iOS app that allows users to search for photos using the Pixabay API, display the results in a photo gallery, and view individual photos in detail. We’ll use SwiftUI for the user interface, Alamofire for networking, and integrate with the Pixabay API for fetching images.

Project Setup

First, create a new SwiftUI project in Xcode. Then, we’ll use CocoaPods to manage our dependencies. Create a Podfile in your project directory with the following content:

platform :ios, '14.0'
use_frameworks!

target 'PhotoExplorer' do
  pod 'Alamofire'
  pod 'SDWebImageSwiftUI'
end

Run pod install in your terminal, then open the .xcworkspace file.

The Photo Model

Let’s start by defining our Photo model:

import Foundation

struct Photo: Identifiable, Codable {
    let id: Int
    let pageURL: String
    let previewURL: String
    let largeImageURL: String
    let user: String
    let tags: String
}

struct PixabayResponse: Codable {
    let total: Int
    let totalHits: Int
    let hits: [Photo]
}

This model matches the JSON structure returned by the Pixabay API.

Networking Service

Next, let’s create a networking service using Alamofire:

import Foundation
import Alamofire

class PixabayService {
    static let shared = PixabayService()
    private init() {}

    private let baseURL = "https://pixabay.com/api/"
    private let apiKey = "YOUR_PIXABAY_API_KEY"

    func searchPhotos(query: String, completion: @escaping (Result<[Photo], Error>) -> Void) {
        let parameters: [String: Any] = [
            "key": apiKey,
            "q": query,
            "image_type": "photo",
            "per_page": 50
        ]

        AF.request(baseURL, parameters: parameters).responseDecodable(of: PixabayResponse.self) { response in
            switch response.result {
            case .success(let pixabayResponse):
                completion(.success(pixabayResponse.hits))
            case .failure(let error):
                completion(.failure(error))
            }
        }
    }
}

Don’t forget to replace "YOUR_PIXABAY_API_KEY" with your actual Pixabay API key.

Main View

Now, let’s create our main view with a search bar and photo grid:

import SwiftUI
import SDWebImageSwiftUI

struct ContentView: View {
    @State private var searchText = "famous quotes"
    @State private var photos: [Photo] = []

    let columns = [GridItem(.adaptive(minimum: 100))]

    var body: some View {
        NavigationView {
            VStack {
                SearchBar(text: $searchText, onSearchButtonClicked: fetchPhotos)

                ScrollView {
                    LazyVGrid(columns: columns, spacing: 20) {
                        ForEach(photos) { photo in
                            NavigationLink(destination: PhotoDetailView(photo: photo)) {
                                PhotoThumbnail(imageURL: photo.previewURL)
                            }
                        }
                    }
                    .padding()
                }
            }
            .navigationTitle("Pixabay Gallery")
        }
        .onAppear(perform: fetchPhotos)
    }

    private func fetchPhotos() {
        PixabayService.shared.searchPhotos(query: searchText) { result in
            switch result {
            case .success(let fetchedPhotos):
                DispatchQueue.main.async {
                    self.photos = fetchedPhotos
                }
            case .failure(let error):
                print("Error fetching photos: \(error)")
            }
        }
    }
}

struct SearchBar: View {
    @Binding var text: String
    var onSearchButtonClicked: () -> Void

    var body: some View {
        HStack {
            TextField("Search photos", text: $text, onCommit: onSearchButtonClicked)
                .textFieldStyle(RoundedBorderTextFieldStyle())
            Button(action: onSearchButtonClicked) {
                Image(systemName: "magnifyingglass")
            }
        }
        .padding()
    }
}

struct PhotoThumbnail: View {
    let imageURL: String

    var body: some View {
        WebImage(url: URL(string: imageURL))
            .resizable()
            .indicator(.activity)
            .transition(.fade(duration: 0.5))
            .scaledToFill()
            .frame(width: 100, height: 100)
            .clipShape(RoundedRectangle(cornerRadius: 10))
    }
}

Detail View

Finally, let’s create our detail view:

import SwiftUI
import SDWebImageSwiftUI

struct PhotoDetailView: View {
    let photo: Photo
    @State private var scale: CGFloat = 1.0

    var body: some View {
        VStack {
            ZoomableImageView(imageURL: photo.largeImageURL, scale: $scale)
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .navigationTitle("Photo Details")
        .toolbar {
            ToolbarItem(placement: .navigationBarTrailing) {
                Button("Reset Zoom") {
                    scale = 1.0
                }
            }
        }
    }
}

struct ZoomableImageView: View {
    let imageURL: String
    @Binding var scale: CGFloat

    var body: some View {
        WebImage(url: URL(string: imageURL))
            .resizable()
            .indicator(.activity)
            .transition(.fade(duration: 0.5))
            .scaledToFit()
            .scaleEffect(scale)
            .gesture(
                MagnificationGesture()
                    .onChanged { value in
                        scale = value.magnitude
                    }
            )
            .onTapGesture(count: 2) {
                if scale > 1 {
                    scale = 1
                } else {
                    scale = 2
                }
            }
    }
}

How It Works

1. When the app launches, it automatically searches for “famous quotes” using the Pixabay API.
2. The search results are displayed in a grid of thumbnails.
3. Users can enter a new search term and tap the search button to fetch new photos.
4. Tapping on a photo thumbnail navigates to the detail view.
5. In the detail view, users can:

• See the full-size photo
• Zoom in/out using pinch gestures or double-tap

This app demonstrates several important iOS development concepts:

• Using SwiftUI for building user interfaces
• Networking with Alamofire
• Integrating with a third-party API (Pixabay)
• Displaying and caching images with SDWebImageSwiftUI
• Implementing zoom functionality
• Navigation and data passing between views

By building this app, you’ve created a functional and interactive photo gallery that fetches real-world data from the internet. You can further enhance this app by adding features like pagination, saving favourite photos, or implementing more advanced search filters.