Flower

Super cool library for Android to manage database caching and networking with ease. It helps you to handle all scenario of API request(success/error/loading) in one place along with database caching. It's inspired from Google's Github Browser Sample. It's built on top of Retrofit and use powerful and elegant kotlin flow api.

You can find companion medium article here

Installation

Add JitPack to your project level build.gradle file

allprojects {
    repositories {
        ...
        maven { url 'https://jitpack.io' }
    }
}

Add Gradle dependency as

dependencies {
    implementation 'com.github.hadiyarajesh:flower:1.0.0'
}

Usage

Prerequisite

• Your Room Dao method must return Flow<YourModelClass>
• Your Retrofit API method must return Flow<ApiResponse<YourModelClass>>
• Add FlowCallAdapterFactory as CallAdapterFactory in your retrofit builder

1. In Repository class

Return the networkBoundResource() function from repository. This function takes following functions as parameter

• fetchFromLocal - It fecth data from local database
• shouldFetchFromRemote - It decide whether network request should be made or use local persistent data if available
• fetchFromRemote - It perform network request operation
• processRemoteResponse - It process result of network response (if requires)
• saveRemoteData - It saves result of network request to local persistent database
• onFetchFailed - It handle network request failure scenario (Non HTTP 200..300 response, exceptions etc)

fun getSomething(): Flow<Resource<YourModelclass>> {
    return networkBoundResources(
        fetchFromLocal = { yourDaoclass.getFromDatabase() },
        shouldFetchFromRemote = { it == null },
        fetchFromRemote = { apiInterface.getFromRemote() },
        processRemoteResponse = { },
        saveRemoteData = { yourDaoclass.saveYourData(it) },
        onFetchFailed {-, _ -> }
    ).flowOn(Dispatchers.IO)
}

2. In View Model class

Collect/transform flow to get 3 different state of request: LOADING, SUCCESS or ERROR

val someVariable: LiveData<Resource<YourModelClass>> = repository.getSomething().map {
    when (it.status) {
        Resource.Status.LOADING -> {
            Resource.loading(null)
        }
        Resource.Status.SUCCESS -> {
            Resource.success(it.data)
        }
        Resource.Status.ERROR -> {
            Resource.error(it.message!!, null)
        }
}.asLiveData(viewModelScope.coroutineContext)

3. In Activity/Fragment class

Observe it in your Activity/Fragment as

viewModel.someVariable.observer(this, Observer {
    when (it.status) {
        Resource.Status.LOADING -> {
            //Show loading message
        }
        Resource.Status.SUCCESS -> {
            //Show success message
        }
        Resource.Status.ERROR -> {
            //Show error message
        }
    }
})

Sample

Sample app is provided here. It fetch random quote from remote api and save it to local persistent database in order to display it on UI.

License

MIT License