🪙 Crypto Ranker: Cryptocurrency Tracking App

Project Description:.

Is an iOS application that fetches data from the CointRanking API and displays a list of the top 100 cryptocurrency coins paginated, showing 20 characters per page.

✨Application Features:

The application successfully implements a three-screen architecture using MVVM and UIKit/SwiftUI interoperability.

1. Coin List (Home Screen):

   • Fetches and displays top 100 cryptocurrencies.
   • Pagination and filtering implemented.
   • UI: Uses a UITableView with embedded SwiftUI CoinListRow cards.
   • Visualization: Displays a sparkline chart (24H data) using SwiftUICharts library.
   • Action: Swipe-to-Favorite functionality.

2. Coin Details:

   • Displays static data (price, rank) and historical chart data.
   • Uses a SwiftUI header for the main metrics.
   • Allows time period filtering (24H, 7D, 30D, 1Y).
   • Hides the tab bar for a focused view.

3. Favorites/Watchlist:

   • Persists user-selected favorite coins using UserDefaults.
   • Synchronized across the entire app via NotificationCenter.

4. Error Handling: Implemented a centralized AppError model and Combine subscriptions in all View Controllers to display non-blocking error dialogs on network failures.

Screenshots 📱

Home (Light Theme)	Crypto Coin Details (Light Theme)	Favourite (Light Theme)

Home (Dark Theme)	Crypto Coin Details (DArk Theme)	Favourite (Light Theme)

🏗️ Architecture & Technology Stack

• Architecture: Model-View-ViewModel (MVVM) with Factory Pattern for dependency injection (DI).
• Networking: Modern Swift Concurrency (async/await) for all API calls.
• State Management: Combine framework with ObservableObject and @Published properties for reactive data flow between ViewModels and Views.
• UI: Hybrid approach combining UIKit (UIViewController, UITableView) with embedded SwiftUI (UIHostingController) for custom cells and views.

Tech-stack used 🛠

Tech Tools	Usage/Purpose
Swift	Language
UIKit	IU
SwiftUI	UI

📦 Dependencies

The project uses Swift Package Manager (or CocoaPods) for the following third-party libraries:

Library	Purpose
SDWebImageSwiftUI	Asynchronously loading and displaying images, including SVG icon support (SDWebImageSVGCoder).
SwiftUICharts (willdale)	Robust and customizable line chart visualization for sparklines and historical data.

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Development Setup ⚙️ and Pre-requisite 📝

The Project uses the free version of Coinranking API :

1. List of coins for list of coins.

⚙️ Setup Coinranking API

This project fetches weather data from the coinranking.com.
To begin the setup, you'll need to create an account and get a free API key.

1. Create an account at coinranking.com
2. Go to API key & Usage
3. Your API key (you can create a new API or use the Auto-generated API key)

update or create the Config file AppConfig.xcconfig and place your API config there

#Insert at ~/ AppConfig.xcconfig

// Configuration settings file format documentation can be found at:
// https://help.apple.com/xcode/#/dev745c5c974
//
COIN_RANKING_API_KEY = <Your coinranking API Key>

Build and Runtime Requirements

• Xcode 15.0 or later
• iOS v15.0 or later
• macOS v10.10 or later

⚙️ Build and Run Instructions

1. Clone the Repository: git clone Crypto-Ranker repository URL
2. Install Dependencies: the project is using CocoaPods,so run pod install)
3. Open Project: Open CryptoCoinranking.xcworkspace.
4. API Key: Update the API_KEY setting in the AppConfig.xcconfig file with a valid CoinRanking API key.
5. Build Target: Select the main application target and run on a modern iOS Simulator.

🧪 Testing and Quality Assurance

• Unit Tests: Coverage for CoinListViewModel and NetworkService logic using Mocks to verify state changes, error handling, and data transformation.
• UI Tests: Verification of the main user flow: application launch, list loading, and navigation to the detail screen.
• Error Handling: Implemented a centralized AppError model and Combine subscriptions in all View Controllers to show non-blocking error dialogs on network failure.

🚧 Challenges Encountered and Solutions

Building a robust application often involves overcoming specific technical hurdles. Below are the key challenges encountered and the solutions implemented, which demonstrate core technical proficiency.

1. 🖼️ Challenge: Displaying Remote SVG Icons

The CoinRanking API provides coin logos in a mix of both PGN and in the SVG (Scalable Vector Graphics) format.

• Problem: Native Apple frameworks (UIKit and SwiftUI) do not natively support rendering remote SVG files, leading to blank icons in the coin list view.
• Solution: Integrated the SDWebImage library along with its SDWebImageSVGCoder component.
• The solution involved explicitly registering the SVGCoder during app startup (SDImageCodersManager.shared.addCoder(...)) and utilizing the WebImage view. This enables the app to automatically download, resize, and cache the vector icons.

License

  Crypto-Ranker-Swift
  Copyright (c) 2025 Awesome Jim (https://github.com/AwesomeJim/Crypto-Ranker).

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.