Simple android client that uses GitHub API to demonstrate one variation of Clean architecture approach. This example only uses a handful of API calls because GitHub provides a lot more and implementing all of them would somewhat beat the purpose of the project. This learning project is dedicated to all Android developers who are trying different ways to build their app (in terms of architecture of course)
The main purpose of the project is to demonstrate how to break your application into several modules, how to use them, how to split the work and via dependency injection and interfaces use functions, classes and their methods etc. as sort of a black box. Given that GitHub provides variation of API calls, making the entire application to support that, even though it's a good idea, would make this project take longer, and beyond its original scope. So we only use some calls, and sacrifice some implementations for the sake of the scope of the project.
As seen in preview above, we have following screens:
Authentication screen, given that it contains single button, will take you to your default browser where you'll login to your github account. We use OAUTH authentication in this app (more on this in installation section). When you successfully login, we save your access token to encrypted shared preferences and send you to the main screen. From that moment on you'll only land on the main screen on each app launch. We also use this access token to authorize all our API calls.
This screen, it's simple purpose is to fetch currently logged in user, and display two pieces of information on the screen which user can open: see repositories and see organisations. These will lead to external browser to your profile following said url.
Here you simply input your query and we fetch whatever you searched for. We only fetch first 10 items, and we provide no pagination in this case. Again, on one hand, it's limitations of this approach, on another it's scope. The purpose here was to provide option to query for something. Once you get results back (in this case list of repositories), you can open its detail preview.
Here currently logged in user will receive all events that are tied to them. That goes from people they follow or people having some interaction on their profile (if someone follows you, or watches your repository, for instance).
At the time of development, when OAUTH application was being created on GitHub, notifications scope was turned off. We have implementation for those, but this screen served as a sort of 'error fallback' screen. We use Lottie animation to indicate that something went wrong, ie maybe app doesn't contain scope, maybe there some other error, and this way the user will for sure know that something went wrong.
This screen is a combination of two API calls. We fetch current user information (but you can build on that and store it locally, how likely user info will change?), and we fetch their top repositories with some basic information (no need to cover screen with so much info)
The user can either get here via search screen or profile screen. We, in a similar fashion to profile screen trigger two API calls. We get basic information about repository (or you can pass that data as a bundle when you navigate, hence no need to one API call), and we get events for that repository (who is watching, who is committing, etc.).
This project is loosely following clean architecture approach as recommended by Antonio Levia in his article Clean architecture for Android with Kotlin: a pragmatic approach for starters. The idea is to split your app into several modules and via dependency injection and interfaces provide their usage (what we said in the intorduction). Modules are as follows:
All data related, from repositories, API calls, mappers for our models, datasource (only its interface) is in here. Essentially core of the app is in this module
Our response and request models, as well as our mapping classes.
Given we have many API calls, to handle them nicely, we split each call into its use-case. That way we can focus on single flow.
Here we provide an implementation for our datasource (this can be local and/or remote); because we implement it in the app module we can use Android specific components (interface is in data module) so the data module (or core) is still isolated, while specific client provides the implementation however they want. And here are all UI parts (fragments, view models, and adapters).
Flow in this case is pretty simple: api call -> datasource -> repository -> usecase -> viewmodel -> fragment
Since we, due to use-cases, only focus on one flow, following this won't be an issue. And we handle data, however we want, so we know what we get back (for instance, in datasource, we might want to re-map our response to some other model because we won't use all that information).
The only main thing that needs configuration is authentication. Firstly, you need to create OAUTH application and once you do, you'll get access to following information:
- clientId
- clientSecret
- redirectUrl
Redirect url can be whatever you put in (whatever as in for testing purposes, for production callback url will be different), so it can be "youAppPackageName://callback" (ex: "airbnb://callback"). Remember what you select to be the scope of your application.
Once you have those 3 pieces of information, add them into AppConst.kt file (or add them to wherever file you prefer).
Finally, update your manifest file; add intent filter into the activity that will run authentication. In this case, since we use a single activity approach, it'll be MainActivity:
`<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data
android:host="callback"
android:scheme="airbnb" />
</intent-filter>`
Now your app is set up, and only thing you need to do is to run it.
This app uses MVVM (Model View View-Model) architecture.
If you want to contribute to this repository, you're always welcome!
If you need any help, feel free to contact me: [email protected].
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