https://github.com/arunkumar9t2/flickr-sample

Sample flickr gallery app with minimal dependencies and RxJava
https://github.com/arunkumar9t2/flickr-sample

Last synced: 12 months ago
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Sample flickr gallery app with minimal dependencies and RxJava

• Host: GitHub
• URL: https://github.com/arunkumar9t2/flickr-sample
• Owner: arunkumar9t2
• Created: 2019-04-07T05:53:40.000Z (about 7 years ago)
• Default Branch: master
• Last Pushed: 2019-04-07T06:34:45.000Z (about 7 years ago)
• Last Synced: 2025-03-16T17:46:12.907Z (over 1 year ago)
• Language: Kotlin
• Size: 6.71 MB
• Stars: 2
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
# Introduction

Simple image search app using the Flickr Image Search API. 

**Features**:

 - Endless scrolling of search results

 - 3 column grid view of images

 - Auto search as you type

## Demo

![enter image description here](https://github.com/arunkumar9t2/flickr-sample/raw/master/art/FlickrAppDemo.gif)

# Overview

 - **RxJava** - Used RxJava for easier concurrency and thread management. 

	Example:

	 - Searching: Ability to search as you type by debouncing keystrokes to avoid unnecessary requests

	 - Cancel existing network requests (both query and paging) when search query changes using `switchMap` operator.

	 - Manage a bound thread pool of size 6 to fetch and decode images concurrently.

 - **OkHttp** - Used for easier networking to fetch `json` and `input stream` for `Bitmap`s.

## Architecture

MVP with Repository to avoid logical code in `Activity` and separate data related code. Loose coupling by making code dependent on interfaces rather than implementations eg: `ImageCache`, `ImagesDataSource`, `ImageLoader`. Explicit dependency on Flickr is avoided and is accessed through contracts.

 - `data` - `ImagesDataSource` is a contract for a source that provides paged searching. `FlickrImagesDataSource` is an implementation backed by `Flickr API`. Also includes data classes for parsing `json` response.

 - `DepedencyInjector` - Utility class to manage dependencies throughout the app. Responsible for managing and providing dependencies when requested. Eg: `DependencyInjector.provideHomePresenter`.

 - `Image Loading` - `ImageLoader` and `ImageCache` are contracts for a system that loads images efficiently by reducing sample size, perform concurrent requests and caching.

 

	- `DefaultImageLoader` - Loader backed by Rx to handle multiple requests and decode images.

	- `MemoryImageCache` - Lru based memory cache to hold few `Bitmap`s in memory.

 - `SchedulerProvider` - Contract to provide various type of `Schedulers` for concurrency. Can be replaced during testing via DI.

 - `Home` - Home feature package that contains, presenter for communicating with data layer, adapter for rendering grid and `HomeActivity`

 - `Test` - Presenter test for search term achieved by injecting `MockImagesDataSource` and testing paging and searches.

# Possible improvements

- `ImageLoading`

		- While current implementation automatically uses `ImageViews` dimensions to downsize source image, there are other cases that could handled for better performance. Currently the load request is not cancelled when the `ImageView` is detached from window and relies on `RecyclerView.Adapter.onViewRecycled` to cancel the request, this could be changed to use `View.onAttachStateListener` to free one of the threads thereby improving load performance during scrolling.

		- Could use battle tested solutions like `Glide` or `Picasso`.

- `Paging`

		- By using [PagedList](https://developer.android.com/reference/android/arch/paging/PagedList) and [PageKeyedDataSource](https://developer.android.com/reference/android/arch/paging/PageKeyedDataSource) to simplify scroll listening, load more and concentrate on API implementations

- `Dagger 2` 

		- Use Dagger 2 instead of custom `DependencyInjector` to achieve compilation safety and scaling.

- `State Restoration`

		- Currently only the search term is restored upon a config change, this could be changed to use `ViewModel` pattern to cache the image list as well to avoid additional network calls.

- `Better Error handling` 

		- When a paged list fails to load, possibly a retry button could be used to restart failed requests.

- `Test` - Additional integration tests to avoid breakage due to 3rd parties.

- `LocalDataSource` - Implement a local data source for provide search results stored on disk.