Networking in Android

REST APIs

REST (Representational State Transfer) APIs are the most common way for Android apps to communicate with servers.

Core concepts
🔸 Uses HTTP methods like GET, POST, PUT, DELETE
🔸 Works with URLs (endpoints)
🔸 Exchanges data usually in JSON format

Common use cases
🔸 User authentication
🔸 Fetching lists (products, posts, users)
🔸 Sending form or transaction data

Benefits
🔸 Platform independent
🔸 Scalable and stateless
🔸 Easy to integrate

Retrofit

Retrofit is a popular HTTP client library for Android used to consume REST APIs.

Key features
🔸 Converts HTTP API into Java/Kotlin interfaces
🔸 Supports annotations for API calls
🔸 Built-in JSON conversion with Gson/Moshi

Why use Retrofit
🔸 Clean and readable code
🔸 Automatic request/response handling
🔸 Easy error and response management

Common usage
🔸 API service interfaces
🔸 Background network calls
🔸 Integration with coroutines or callbacks

JSON Parsing

JSON Parsing converts JSON responses from APIs into usable objects.

Parsing approaches
🔸 Manual parsing using JSONObject
🔸 Automatic parsing using Gson or Moshi
🔸 Model-based mapping

Why it matters
🔸 Converts raw data into structured objects
🔸 Simplifies UI updates
🔸 Reduces data handling errors

Best practices
🔸 Match JSON keys with model fields
🔸 Handle null values properly
🔸 Use proper data types

Error Handling

Error handling ensures your app behaves gracefully when network issues occur.

Common network errors
🔸 No internet connection
🔸 Server errors (4xx, 5xx)
🔸 Timeout or slow responses

Best practices
🔸 Show user-friendly error messages
🔸 Retry failed requests when appropriate
🔸 Handle API error responses properly

Why it’s important
🔸 Improves user experience
🔸 Prevents app crashes
🔸 Makes apps more reliable

Pagination

Pagination loads data in chunks instead of all at once.

Why pagination is needed
🔸 Improves performance
🔸 Reduces memory usage
🔸 Faster initial loading

Common pagination types
🔸 Page-based (page, limit)
🔸 Offset-based
🔸 Cursor-based

Use cases
🔸 Social media feeds
🔸 Product listings
🔸 Search results