Slide (Not Glide 😄) - Android Image Loading Library

This project implements a custom image downloading and caching library for Android, along with an example app that demonstrates its usage.

⚠️This is a project created in ~3h which means its missing tests, and also might be not that clean I'd like it to be. Please consider this when reviewing.

Project Structure

ImageLoader Library (imageloader module)

A custom image loading library that provides:

• Image downloading from URLs
• Memory and disk caching with 4-hour TTL
• Manual cache invalidation
• Support for both Kotlin and Java

Example App (app module)

A sample application that:

• Fetches a JSON list of images from the provided API
• Displays images in a RecyclerView using the custom image loader
• Shows image ID and title
• Includes a button to manually invalidate the cache

Features

Image Loading Library

• URL-based image loading: Load images from any HTTP/HTTPS URL
• Dual caching system: Memory cache (LRU) + disk cache
• TTL support: Cached images are valid for 4 hours
• Manual cache invalidation: Clear cache on demand
• Placeholder support: Show placeholder while loading
• Thread-safe: All operations are thread-safe
• Java/Kotlin compatibility: Works with both languages

Example App Features

• Loads image list from: https://acharyaprashant.org/api/v2/content/misc/media-coverages?limit=100
• RecyclerView with custom adapter
• Shows loading indicator
• Cache invalidation button
• Error handling with toast messages

Usage

Kotlin && Java

Slide.load(
    url = image.url,
    imageView = imageView,
    loadingPlaceholderResId = R.drawable.placeholder_loading,
    failurePlaceholderResId = R.drawable.placeholder_failure
)

// Invalidate cache
Slide.invalidateCache()

Library Architecture

Core Components

1. ImageLoadingClient: Class that encapsulates the image loading logic and takes care of concurrency.
2. MemorySource: Handles memory caching with TTL
3. DiskSource: Handles disk caching with TTL
4. NetworkSource: Downloads images

Caching Strategy

• Memory Cache: LRU cache with 10MB limit
• Disk Cache: Files stored in app's cache directory
• TTL: 4 hours expiration time
• Cache Keys: MD5 hash of image URL and custom tags

Dependencies

The library has minimal dependencies:

• Android SDK (API 24+)
• No external libraries (no Glide, Picasso, etc.)

Requirements Met

✅ Custom image downloading and caching library
✅ No external libraries like Glide
✅ Fetches JSON from provided URL
✅ Example app using the library
✅ 4-hour cache validity
✅ Manual cache invalidation
✅ Shows image and ID in list
✅ Android View system (not Jetpack Compose)
✅ Java and Kotlin support

Building the Project

1. Clone the repository
2. Open in Android Studio
3. Sync gradle files
4. Run the app

API Usage Example

The app demonstrates loading images from:

https://zipoapps-storage-test.nyc3.digitaloceanspaces.com/image_list.json

Each image item contains:

• id: Unique identifier
• title: Image file name extracted from the image url
• imageUrl: Image url

Cache Management

The cache automatically:

• Stores images for 4 hours
• Cleans expired entries
• Handles storage errors gracefully
• Provides manual invalidation