Learn Modern Android Development

Coroutines & Dispatchers

Asynchronous execution without blocking the main UI thread. Always choose the correct dispatcher:

viewModelScope.launch {
    // 1. Heavy Network/Disk I/O on background thread
    val data = withContext(Dispatchers.IO) {
        apiService.fetchUserData()
    }
    // 2. Automatically resumes on Dispatchers.Main for UI update
    _uiState.value = UserUiState.Success(data)
}

• Dispatchers.Main • UI interactions & Compose state updates
• Dispatchers.IO • Network requests, Room database queries, disk files
• Dispatchers.Default • Heavy CPU calculations, JSON parsing, sorting

StateFlow vs SharedFlow

Reactive data streams designed for Android lifecycle awareness:

// Holds current state, emits last known value to new collectors
private val _count = MutableStateFlow(0)
val count: StateFlow<Int> = _count.asStateFlow()

// For one-off events (Navigation, Toasts, Snackbars)
private val _event = MutableSharedFlow<UiEvent>()
val event: SharedFlow<UiEvent> = _event.asSharedFlow()

Use StateFlow for persistent UI state and SharedFlow for one-off events.

State Hoisting & Recomposition

In Compose, UI components are pure functions. Pass state down, send events up:

// Stateless Composable (Re-usable & Testable)
@Composable
fun CounterButton(count: Int, onIncrement: () -> Unit) {
    Button(onClick = onIncrement) {
        Text("Count: $count")
    }
}

// Stateful Parent (Owns the State)
@Composable
fun CounterContainer() {
    var count by rememberSaveable { mutableStateOf(0) }
    CounterButton(count = count, onIncrement = { count++ })
}

LazyColumn Performance

Efficiently rendering millions of items with stable keys to avoid jank:

LazyColumn(
    contentPadding = PaddingValues(16.dp),
    verticalArrangement = Arrangement.spacedBy(8.dp)
) {
    // ALWAYS provide a unique stable key!
    items(items = appsList, key = { app -> app.packageId }) { app ->
        AppRowItem(app = app)
    }
}

Providing key = { it.id } allows Compose to reposition items during sorting without recomposing unchanged elements.

Flutter vs Jetpack Compose

State Management Choice

Popular state management architectures for production Flutter applications:

• Riverpod: Compile-safe, testable provider replacement without BuildContext requirements.
• Bloc / Cubit: Strict separation of business events and UI states, ideal for enterprise projects.
• Provider: Lightweight inherited widget wrapper suitable for simple to medium utilities.

Speed Up Gradle Build Times

Add these flags into your gradle.properties file to decrease compilation time by up to 60%:

# Enable Gradle build caching across tasks
org.gradle.caching=true

# Parallel execution across multi-module projects
org.gradle.parallel=true

# Configuration on demand
org.gradle.configureondemand=true

# Allocate JVM memory heap
org.gradle.jvmargs=-Xmx4096m -XX:+UseParallelGC

Top Productivity Shortcuts

• Search Everywhere (Files, Classes, Symbols) Shift + Shift
• Reformat Code & Optimize Imports Ctrl + Alt + L
• Extract Composable / Method Ctrl + Alt + M
• Inspect Call Hierarchy Ctrl + Alt + H