Integrating GraphQL in Android with Kotlin and Jetpack Compose

GraphQL is gaining popularity as a modern API design approach, offering flexibility and efficiency compared to traditional REST APIs. In this blog post, we’ll explore how to integrate GraphQL in Android using Kotlin and Jetpack Compose. We’ll demonstrate fetching data from a GraphQL API and displaying it on the UI, evaluate alternatives to GraphQL, and look at recent projects or companies leveraging GraphQL.

Source: https://graphql.org/

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Why GraphQL?

GraphQL, developed by Facebook in 2012 and open-sourced in 2015, is a query language for APIs that allows clients to request exactly the data they need. Unlike REST, GraphQL consolidates data fetching into a single endpoint and avoids over-fetching or under-fetching data. Key benefits include:

• Flexible Queries: Fetch only the fields required.

• Single Endpoint: Simplifies API design.

• Strong Typing: Errors are easier to catch with a well-defined schema.

• Real-Time Data: Supports subscriptions for live updates.

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Setting Up GraphQL in Android with Kotlin

To integrate GraphQL in an Android app, we’ll use Apollo GraphQL, a powerful GraphQL client for Kotlin Multiplatform.

Step 1: Add Dependencies

Add the Apollo library to your build.gradle file:

plugins {
    id("com.apollographql.apollo3") version "3.9.0"
}

dependencies {
    implementation("com.apollographql.apollo3:apollo-runtime:3.9.0")
}

apollo {
    packageName.set("com.example.graphql")
}

Step 2: Create a GraphQL Schema

Save your GraphQL queries in the src/main/graphql/com/example/graphql directory. For instance:

query GetCharacter {
    characters {
        results {
            id
            name
            status
        }
    }
}

Apollo will generate Kotlin classes for the query automatically.

Step 3: Initialize Apollo Client

Set up the Apollo Client in your application:

import com.apollographql.apollo3.ApolloClient

val apolloClient = ApolloClient.Builder()
    .serverUrl("https://rickandmortyapi.com/graphql")
    .build()

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Fetching Data from GraphQL and Displaying with Compose

Let’s fetch data using the generated GetCharacterQuery class and display it using Jetpack Compose.

Fetching Data

import com.example.graphql.GetCharacterQuery
import kotlinx.coroutines.flow.collect
import kotlinx.coroutines.flow.flow
import kotlinx.coroutines.runBlocking

fun fetchCharacters(): Flow<List<GetCharacterQuery.Result?>> = flow {
    val response = apolloClient.query(GetCharacterQuery()).execute()
    emit(response.data?.characters?.results ?: emptyList())
}

Displaying Data in Compose

import androidx.compose.foundation.layout.*
import androidx.compose.foundation.text.BasicText
import androidx.compose.runtime.*
import androidx.compose.ui.Modifier
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import kotlinx.coroutines.launch

@Composable
fun CharacterListScreen() {
    var characters by remember { mutableStateOf<List<GetCharacterQuery.Result?>>(emptyList()) }
    val scope = rememberCoroutineScope()

    LaunchedEffect(Unit) {
        scope.launch {
            fetchCharacters().collect { characters = it }
        }
    }

    Column(modifier = Modifier.padding(16.dp)) {
        characters.forEach { character ->
            character?.let {
                BasicText(text = "Name: ${it.name}, Status: ${it.status}")
                Spacer(modifier = Modifier.height(8.dp))
            }
        }
    }
}

@Preview
@Composable
fun PreviewCharacterListScreen() {
    CharacterListScreen()
}

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Alternatives to GraphQL

While GraphQL offers unique advantages, other options may suit specific use cases better:

REST APIs

• Strengths: Simplicity, widespread adoption, caching support via HTTP.

• Limitations: Over-fetching or under-fetching data.

gRPC

• Strengths: Efficient binary serialization, bi-directional streaming, and great performance.

• Limitations: Less flexible for clients, harder to debug.

Firebase Realtime Database

• Strengths: Real-time synchronization for mobile apps.

• Limitations: Limited query flexibility compared to GraphQL.

Which One to Choose?

• Choose GraphQL when you need flexible data fetching, strong typing, or real-time capabilities.

• Choose REST for simpler, traditional APIs.

• Choose gRPC for high-performance communication between microservices.

Real-World Examples

• GraphQL: Facebook, GitHub, Shopify, Netflix.
• REST API: Twitter, Reddit, most public-facing APIs.
• gRPC: Google Cloud services, Kubernetes, Uber.

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Companies and Projects Using GraphQL

1. Facebook: Originally created GraphQL for its mobile apps to improve performance.

2. GitHub: Provides a public GraphQL API for developers.

3. Shopify: Uses GraphQL for efficient e-commerce data fetching.

4. Netflix: Leverages GraphQL for flexible data retrieval across multiple platforms.

5. Airbnb: Implemented GraphQL to accelerate development and deliver richer user experiences.

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Summary

GraphQL combined with Kotlin and Jetpack Compose provides a powerful toolkit for building modern Android applications. It simplifies data fetching, reduces boilerplate code, and enhances app performance. As we’ve seen, integrating GraphQL in an Android app is straightforward and offers significant flexibility compared to traditional APIs.

Try integrating GraphQL into your next Android project and experience the benefits firsthand!

More information about GraphQL: Apollo GraphQL , Github GraphQL API, HyGraph, Facebook Graph API 

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