Use Supabase with Android Kotlin | Supabase Docs (original) (raw)

Learn how to create a Supabase project, add some sample data to your database, and query the data from an Android Kotlin app.

Create a Supabase project

Go to database.new and create a new Supabase project.

When your project is up and running, go to the Table Editor, create a new table and insert some data.

Alternatively, you can run the following snippet in your project's SQL Editor. This will create a instruments table with some sample data.

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-- Create the tablecreate table instruments (  id bigint primary key generated always as identity,  name text not null);-- Insert some sample data into the tableinsert into instruments (name)values  ('violin'),  ('viola'),  ('cello');alter table instruments enable row level security;

Make the data in your table publicly readable by adding an RLS policy:

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create policy "public can read instruments"on public.instrumentsfor select to anonusing (true);

Create an Android app with Android Studio

Open Android Studio > New > New Android Project.

Install the Dependencies

Open build.gradle.kts (app) file and add the serialization plug, Ktor client, and Supabase client.

Replace the version placeholders $kotlin_version with the Kotlin version of the project, and $supabase_version and $ktor_version with the respective latest versions.

The latest supabase-kt version can be found here and Ktor version can be found here.

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plugins {  ...  kotlin("plugin.serialization") version "$kotlin_version"}...dependencies {  ...  implementation(platform("io.github.jan-tennert.supabase:bom:$supabase_version"))  implementation("io.github.jan-tennert.supabase:postgrest-kt")  implementation("io.ktor:ktor-client-android:$ktor_version")}

Add internet access permission

Add the following line to the AndroidManifest.xml file under the manifest tag and outside the application tag.

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...<uses-permission android:name="android.permission.INTERNET" />...

Initialize the Supabase client

You can create a Supabase client whenever you need to perform an API call.

For the sake of simplicity, we will create a client in the MainActivity.kt file at the top just below the imports.

Replace the supabaseUrl and supabaseKey with your own:

Project URL

Anon key

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import ...val supabase = createSupabaseClient(    supabaseUrl = "https://xyzcompany.supabase.co",    supabaseKey = "your_public_anon_key"  ) {    install(Postgrest)}...

Create a data model for instruments

Create a serializable data class to represent the data from the database.

Add the following below the createSupabaseClient function in the MainActivity.kt file.

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@Serializabledata class Instrument(    val id: Int,    val name: String,)

Query data from the app

Use LaunchedEffect to fetch data from the database and display it in a LazyColumn.

Replace the default MainActivity class with the following code.

Note that we are making a network request from our UI code. In production, you should probably use a ViewModel to separate the UI and data fetching logic.

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class MainActivity : ComponentActivity() {    override fun onCreate(savedInstanceState: Bundle?) {        super.onCreate(savedInstanceState)        setContent {            SupabaseTutorialTheme {                // A surface container using the 'background' color from the theme                Surface(                    modifier = Modifier.fillMaxSize(),                    color = MaterialTheme.colorScheme.background                ) {                    InstrumentsList()                }            }        }    }}@Composablefun InstrumentsList() {    var instruments by remember { mutableStateOf<List<Instrument>>(listOf()) }    LaunchedEffect(Unit) {        withContext(Dispatchers.IO) {            instruments = supabase.from("instruments")                              .select().decodeList<Instrument>()        }    }    LazyColumn {        items(            instruments,            key = { instrument -> instrument.id },        ) { instrument ->            Text(                instrument.name,                modifier = Modifier.padding(8.dp),            )        }    }}

Start the app

Run the app on an emulator or a physical device by clicking the Run app button in Android Studio.