Android Development Best Practices: Lessons from 7+ Years of Experience

After 7+ years of Android development, working on everything from news applications to fintech solutions, I've learned that building great mobile apps goes beyond just writing code. Here are some key practices that have consistently helped me deliver high-quality applications.

Architecture Matters

One of the most important lessons I've learned is that architecture decisions made early in a project have long-lasting impacts. Over the years, I've seen the evolution from simple MVC patterns to more sophisticated approaches:

MVVM with Clean Architecture

I've found that combining MVVM with Clean Architecture principles creates maintainable and testable code:

class UserRepository @Inject constructor(
    private val remoteDataSource: UserRemoteDataSource,
    private val localDataSource: UserLocalDataSource
) {
    suspend fun getUser(id: String): Result<User> {
        return try {
            val user = remoteDataSource.getUser(id)
            localDataSource.saveUser(user)
            Result.success(user)
        } catch (e: Exception) {
            // Fallback to local data
            localDataSource.getUser(id)?.let { 
                Result.success(it) 
            } ?: Result.failure(e)
        }
    }
}

Dependency Injection Evolution

I've worked with various DI frameworks throughout my career:

• Dagger2: Powerful but complex setup
• Hilt: Simplified Dagger for Android
• Koin: Lightweight and Kotlin-friendly

Each has its place, but I've found Hilt strikes the best balance for most Android projects.

Testing Strategy

A robust testing strategy has saved me countless hours of debugging:

Unit Tests

@Test
fun `when user login is successful, should return user data`() = runTest {
    // Given
    val mockUser = User("123", "John Doe")
    coEvery { userRepository.login(any(), any()) } returns Result.success(mockUser)
    
    // When
    val result = loginUseCase.execute("email", "password")
    
    // Then
    assertTrue(result.isSuccess)
    assertEquals(mockUser, result.getOrNull())
}

UI Tests with Espresso and Kaspresso

For UI testing, I've found Kaspresso to be a game-changer. It reduces flakiness and provides better readability:

@Test
fun loginFlowTest() = run {
    step("Enter valid credentials") {
        emailInput.typeText("[email protected]")
        passwordInput.typeText("password123")
    }
    
    step("Click login button") {
        loginButton.click()
    }
    
    step("Verify navigation to main screen") {
        mainScreen.isDisplayed()
    }
}

Modern Android Development

The Android ecosystem has evolved significantly, and staying current is crucial:

Jetpack Compose

The declarative UI paradigm has changed how we think about UI development:

@Composable
fun UserProfile(user: User, onEditClick: () -> Unit) {
    Card(
        modifier = Modifier
            .fillMaxWidth()
            .padding(16.dp)
    ) {
        Column(modifier = Modifier.padding(16.dp)) {
            Text(
                text = user.name,
                style = MaterialTheme.typography.headlineSmall
            )
            Text(
                text = user.email,
                style = MaterialTheme.typography.bodyMedium,
                color = MaterialTheme.colorScheme.onSurfaceVariant
            )
            
            Button(
                onClick = onEditClick,
                modifier = Modifier.align(Alignment.End)
            ) {
                Text("Edit Profile")
            }
        }
    }
}

Kotlin Coroutines

Asynchronous programming became much cleaner with coroutines:

class NewsViewModel @Inject constructor(
    private val repository: NewsRepository
) : ViewModel() {
    
    private val _uiState = MutableStateFlow(NewsUiState.Loading)
    val uiState = _uiState.asStateFlow()
    
    fun loadNews() {
        viewModelScope.launch {
            repository.getLatestNews()
                .catch { exception ->
                    _uiState.value = NewsUiState.Error(exception.message)
                }
                .collect { news ->
                    _uiState.value = NewsUiState.Success(news)
                }
        }
    }
}

Performance Optimization

Performance has always been critical, especially for applications serving large user bases:

Memory Management

• Use WeakReference for listeners and callbacks
• Implement proper lifecycle management
• Monitor memory usage with profilers

Network Optimization

@Serializable
data class ApiResponse<T>(
    @SerialName("data") val data: T?,
    @SerialName("error") val error: String?
)

// Using Ktor with custom serialization
class ApiClient {
    private val client = HttpClient(CIO) {
        install(ContentNegotiation) {
            json(Json {
                ignoreUnknownKeys = true
                coerceInputValues = true
            })
        }
        install(HttpTimeout) {
            requestTimeoutMillis = 30_000
        }
    }
}

Security Considerations

Working on fintech and news applications taught me the importance of security:

• Certificate Pinning: Prevent man-in-the-middle attacks
• Data Encryption: Encrypt sensitive data at rest
• ProGuard/R8: Obfuscate code and reduce APK size
• Network Security Config: Control network security settings

Continuous Integration

Automating builds and deployments has been crucial for team productivity:

# Example GitHub Actions workflow
name: Android CI
on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Setup JDK
        uses: actions/setup-java@v2
        with:
          java-version: '11'
      - name: Run tests
        run: ./gradlew test
      - name: Run UI tests
        run: ./gradlew connectedAndroidTest

Looking Forward

The Android development landscape continues to evolve:

• Kotlin Multiplatform: Share business logic across platforms
• Compose Multiplatform: Write UI once, deploy everywhere
• Android 15+: New features and capabilities

Conclusion

Building great Android applications requires a combination of technical skills, architectural thinking, and continuous learning. The practices I've shared here have served me well across different projects and teams.

What matters most is not just following best practices, but understanding why they exist and adapting them to your specific context and requirements.

What are your favorite Android development practices? I'd love to hear about your experiences in the comments or connect with me on LinkedIn.