Using the KingFisher library in iOS development.
Tags: ios, apple, mobile, swift
Published: 2024-06-22 17:30:11

The Kingfisher library is a valuable tool for efficiently loading and displaying images in iOS applications. Since its emergence about 8 years ago, the iOS community has widely adopted it due to its simplicity, performance, and robust features. Kingfisher is an open-source library with over 200 contributors to date and more than 2,500 commits.

**Advantages offered by the library:**

**_Efficient Loading_**: One of Kingfisher’s main advantages is its asynchronous image loading, ensuring that the application remains responsive while images are downloaded. This is essential for providing a smooth user experience, especially in image-heavy apps.

**_Automatic Cache_**: Kingfisher automatically manages image caching, eliminating the need for manual intervention. This not only improves the efficiency of the application but also saves bandwidth and speeds up loading times for previously downloaded images.

**_Simple Integration_**: The library offers smooth integration with UIImageView, simplifying the process of loading and displaying images. With just a few lines of code, you can implement advanced functionality such as displaying placeholder images during download.

**_Visual Feature Support_**: Kingfisher supports placeholders, smooth transitions, and prevention of memory retention issues.

## Implementing the Kingfisher Library in iOS Development: A Practical Example

Recently, I integrated the library into my Pokedex project, which is simple but can experience delays in loading images due to the number of Pokémon to be displayed. The use of Kingfisher fits perfectly in this scenario. Here’s a practical implementation example:

    
    import SwiftUI
    import Kingfisher
    struct PokemonCell: View {

    let pokemon: PokemonModel
    @State private var image: UIImage?
    
    var body: some View {
        let color = Color.pokemon(type: pokemon.pokemonType)
        ZStack {
            VStack {
                HStack {
                    title
                    Spacer()
                    type
                }
                .padding(.top, 10)
                .padding(.horizontal, 10)
                
                if let url = URL(string: pokemon.imageUrl) {
                    KFImage(url)
                        .placeholder {
                            ProgressView()
                        }
                        .resizable()
                        .scaledToFit()
                        .frame(width: 130, height: 150)
                        .padding(10)
                }
            }
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .background(color)
        .cornerRadius(12)
        .shadow(color: color.opacity(0.7), radius: 6, x: 0.0, y: 0.0)
    }
    
    var title: some View {
        Text(pokemon.name.capitalized)
            .font(.headline).bold()
            .foregroundColor(.white)
    }
        
    var type: some View {
        Text(pokemon.pokemonType.rawValue)
            .font(.subheadline).bold()
            .foregroundColor(.white)
            .padding(.horizontal, 10)
            .padding(.vertical, 6)
            .overlay(
                RoundedRectangle(cornerRadius: 20)
                    .fill(Color.white.opacity(0.25))
            )
    }

As you can see, the implementation is straightforward. Follow the steps in this example:

**Import the Kingfisher library: Make sure to add import Kingfisher at the beginning of your Swift file to access the library's resources.**

**Define your SwiftUI Cell: In the example above, I created the PokemonCell structure to represent the Pokémon cell. The image URL comes from the PokemonModel model (remember that I used the MVVM architecture in this project).**

**Simple Loading and Caching: Use KFImage(url) to load the image from the URL provided by the template. The .placeholder block displays a progress indicator while loading. Kingfisher automatically takes care of caching, ensuring a fast and efficient user experience.**

**And with that, you already have everything you need!**