SimpleDatabase

A simple database class for Android written in Kotlin.

SimpleDatabase allows you to store the following data types in the Android SharedPreferences:

String
Boolean
Int
ArrayList<String>
any Gson-serializable and deserializable class using getObject<T>() and putObject<T>()
a list of any Gson-serializable and deserializable class using getListObject<T>() and putListObject<T>()

The project internally has a dependency on Gson.

Installation

You can add the library to your project using Jitpack.

First, add Jitpack to your root build.gradle if it isn't there already:

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

Then add SimpleDatabase to your app's build.gradle:

dependencies {
    implementation 'com.github.tinacious:simpledatabase:1.1.0'
}

Replace 1.1.0 with the latest version.

Usage

Basic Implementation

You can pass any instance of android.content.SharedPreferences to the SimpleDatabase class.

Here is an example where we get an instance of a private SharedPreferences:

val sharedPreferences = context
    .getSharedPreferences(
        "${context.packageName}_preferences",
        Context.MODE_PRIVATE
    )

val database = SimpleDatabase(sharedPreferences)

KeyValueStorage

Below is a suggested approach to using it. We create a class KeyValueStorage that implements SimpleDatabase:

import android.content.Context
import com.tinaciousdesign.simpledatabase.SimpleDatabase
import com.tinaciousdesign.simpledatabase.SimpleDatabaseImpl


/**
 * Simple key value storage using SimpleDatabase
 */
class KeyValueStorage private constructor(private val delegate: SimpleDatabase) :
    SimpleDatabase by delegate {
    companion object {
        @JvmStatic
        fun getInstance(context: Context): KeyValueStorage {
            val sharedPreferences = context.getSharedPreferences(
                "${context.packageName}_preferences",
                Context.MODE_PRIVATE
            )
            val simpleDatabase = SimpleDatabaseImpl(sharedPreferences)

            return KeyValueStorage(simpleDatabase)
        }
    }
}

Then we can access this instance by calling val keyValueStorage = KeyValueStorage.getInstance(context).

The sample project in app has an example implementation that uses the dependencies container pattern for dependency injection.

Usage with Koin

You can create the above-mentioned class and provide it with Koin in one of your modules:

val servicesModule = module {
    single { KeyValueStorage.getInstance(androidContext()) }
}

Then you can use it in any Koin component as follows:

class MyActivity : AppCompatActivity() {
    private val keyValueStorage by inject<KeyValueStorage>()
}

Inspiration

I was inspired by TinyDB to make a simpler Kotlin version.

tinacious / simpledatabase