2.Decode a Json file and fetch data.md

🔷 2.Decode a Json file and fetch data

🔶 Encoder, Decoder, Codable

• Encoder + Decoder

Adoption Codable on any custom types enables us to serialize them to and from any of the built-in data formats by the Jdon Encoder and Json Decoder classes

• Codable API The Swift library defines a standardized approach to data encoding and decoding.

We need to adopt this approach by implementing the Encodable and Decodable protocols [Codable type alias] on your custom types.

1.To decode a local Json file to populate a SwiftUI view with this data.

2.To make this decoder function algorithm reusable anywhere.

3.To make this decoder a generics to decode any JSON file

//  CodableBundleExtension.swift
// CodableBundleExtension
extension Bundle {
	func decode(_ file: String) -> [CoverImage] {
		// 1.Locate the json file
		guard let url = self.url(forResource: file, withExtension: nil) else {
			fatalError("Failed to locate \(file) in bundle")
		}
		// 2.Create a property for the data
		guard let data = try? Data(contentsOf: url) else {
			fatalError("Failed to load \(file) from bundle")
		}
		// 3.Create a decoder
		let decoder = JSONDecoder()

		// 4.Create a property for the decoded data
		guard let loaded = try? decoder.decode([CoverImage].self, from: data) else {
			fatalError("Failed to decode \(file) from bundle.")
		}

		// 5.Return the ready-to-use data
		return loaded
	}
}

//  CoverImageView.swift
import SwiftUI

let coverImages: [CoverImage] = Bundle.main.decode("covers.json")

// MARK: -  BODY
struct CoverImageView: View {
	var body: some View {
		TabView {
			ForEach(coverImages) { item in
				Image(item.name)
					.resizable()
				.scaledToFill()
			} //: LOOP
		} //: TAB
		.tabViewStyle(.page)
	}
}

import SwiftUI

struct ContentView: View {
var body: some View {
NavigationView {
	List {
		CoverImageView()
			.frame(height: 300)
			.listRowInsets(EdgeInsets(top: 0, leading: 0, bottom: 0, trailing: 0))
	} //: LIST
	.navigationBarTitle("한국 멸종위기 동물들", displayMode: .large)
	.listStyle(.plain)
} //: NAVIGATION
}
}