android-jetpack-compose✓ تایید شده

محتوای SKILL.md

---
name: android-jetpack-compose
description: Use when building Android UIs with Jetpack Compose, managing state with remember/mutableStateOf, or implementing declarative UI patterns.
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---

# Android - Jetpack Compose

Modern declarative UI toolkit for building native Android interfaces.

## Key Concepts

### State Management

Compose provides several ways to manage state:

- **remember**: Survives recomposition
- **rememberSaveable**: Survives configuration changes
- **mutableStateOf**: Creates observable state
- **derivedStateOf**: Computed state that updates when dependencies change

```kotlin
@Composable
fun Counter() {
    var count by remember { mutableStateOf(0) }

    Column {
        Text("Count: $count")
        Button(onClick = { count++ }) {
            Text("Increment")
        }
    }
}

// With saveable for configuration changes
@Composable
fun SearchField() {
    var query by rememberSaveable { mutableStateOf("") }

    TextField(
        value = query,
        onValueChange = { query = it },
        placeholder = { Text("Search...") }
    )
}
```

### State Hoisting

Lift state up to make composables stateless and reusable:

```kotlin
// Stateless composable
@Composable
fun NameInput(
    name: String,
    onNameChange: (String) -> Unit,
    modifier: Modifier = Modifier
) {
    TextField(
        value = name,
        onValueChange = onNameChange,
        label = { Text("Name") },
        modifier = modifier
    )
}

// Stateful parent
@Composable
fun UserForm() {
    var name by remember { mutableStateOf("") }

    NameInput(
        name = name,
        onNameChange = { name = it }
    )
}
```

### ViewModel Integration

```kotlin
class UserViewModel : ViewModel() {
    private val _uiState = MutableStateFlow(UserUiState())
    val uiState: StateFlow<UserUiState> = _uiState.asStateFlow()

    fun updateName(name: String) {
        _uiState.update { it.copy(name = name) }
    }

    fun saveUser() {
        viewModelScope.launch {
            _uiState.update { it.copy(isLoading = true) }
            try {
                userRepository.save(_uiState.value.toUser())
                _uiState.update { it.copy(isLoading = false, isSaved = true) }
            } catch (e: Exception) {
                _uiState.update { it.copy(isLoading = false, error = e.message) }
            }
        }
    }
}

@Composable
fun UserScreen(viewModel: UserViewModel = viewModel()) {
    val uiState by viewModel.uiState.collectAsStateWithLifecycle()

    UserContent(
        uiState = uiState,
        onNameChange = viewModel::updateName,
        onSave = viewModel::saveUser
    )
}
```

## Best Practices

### Composable Function Guidelines

```kotlin
// Use Modifier as first optional parameter
@Composable
fun CustomCard(
    title: String,
    modifier: Modifier = Modifier,
    onClick: () -> Unit = {}
) {
    Card(
        modifier = modifier.clickable(onClick = onClick)
    ) {
        Text(
            text = title,
            modifier = Modifier.padding(16.dp)
        )
    }
}

// Use slot APIs for flexible content
@Composable
fun CustomScaffold(
    topBar: @Composable () -> Unit = {},
    bottomBar: @Composable () -> Unit = {},
    content: @Composable (PaddingValues) -> Unit
) {
    Scaffold(
        topBar = topBar,
        bottomBar = bottomBar,
        content = content
    )
}
```

### Efficient Recomposition

```kotlin
// Use keys for list items
@Composable
fun UserList(users: List<User>) {
    LazyColumn {
        items(
            items = users,
            key = { it.id }  // Stable key for efficient updates
        ) { user ->
            UserItem(user)
        }
    }
}

// Use derivedStateOf for expensive computations
@Composable
fun FilteredList(items: List<Item>, query: String) {
    val filteredItems by remember(items, query) {
        derivedStateOf {
            items.filter { it.name.contains(query, ignoreCase = true) }
        }
    }

    LazyColumn {
        items(filteredItems) { item ->
            ItemRow(item)
        }
    }
}
```

### Side Effects

```kotlin
// LaunchedEffect for coroutine-based side effects
@Composable
fun UserProfile(userId: String, viewModel: UserViewModel) {
    LaunchedEffect(userId) {
        viewModel.loadUser(userId)
    }

    // UI content
}

// DisposableEffect for cleanup
@Composable
fun LifecycleAwareComponent(lifecycle: Lifecycle) {
    DisposableEffect(lifecycle) {
        val observer = LifecycleEventObserver { _, event ->
            // Handle lifecycle events
        }
        lifecycle.addObserver(observer)

        onDispose {
            lifecycle.removeObserver(observer)
        }
    }
}

// SideEffect for non-suspend side effects
@Composable
fun AnalyticsScreen(screenName: String) {
    SideEffect {
        analytics.logScreenView(screenName)
    }
}
```

## Common Patterns

### Navigation with Navigation Compose

```kotlin
@Composable
fun AppNavigation() {
    val navController = rememberNavController()

    NavHost(navController = navController, startDestination = "home") {
        composable("home") {
            HomeScreen(
                onNavigateToDetail = { id ->
                    navController.navigate("detail/$id")
                }
            )
        }
        composable(
            route = "detail/{itemId}",
            arguments = listOf(navArgument("itemId") { type = NavType.StringType })
        ) { backStackEntry ->
            val itemId = backStackEntry.arguments?.getString("itemId")
            DetailScreen(itemId = itemId)
        }
    }
}
```

### Material 3 Theming

```kotlin
@Composable
fun AppTheme(
    darkTheme: Boolean = isSystemInDarkTheme(),
    content: @Composable () -> Unit
) {
    val colorScheme = when {
        darkTheme -> darkColorScheme(
            primary = Purple80,
            secondary = PurpleGrey80,
            tertiary = Pink80
        )
        else -> lightColorScheme(
            primary = Purple40,
            secondary = PurpleGrey40,
            tertiary = Pink40
        )
    }

    MaterialTheme(
        colorScheme = colorScheme,
        typography = Typography,
        content = content
    )
}

// Using theme values
@Composable
fun ThemedCard() {
    Card(
        colors = CardDefaults.cardColors(
            containerColor = MaterialTheme.colorScheme.surfaceVariant
        )
    ) {
        Text(
            text = "Themed content",
            style = MaterialTheme.typography.bodyLarge,
            color = MaterialTheme.colorScheme.onSurfaceVariant
        )
    }
}
```

### Lists and Grids

```kotlin
@Composable
fun ProductGrid(products: List<Product>) {
    LazyVerticalGrid(
        columns = GridCells.Adaptive(minSize = 160.dp),
        contentPadding = PaddingValues(16.dp),
        horizontalArrangement = Arrangement.spacedBy(16.dp),
        verticalArrangement = Arrangement.spacedBy(16.dp)
    ) {
        items(products, key = { it.id }) { product ->
            ProductCard(product)
        }
    }
}

// Sticky headers
@Composable
fun ContactList(contacts: Map<Char, List<Contact>>) {
    LazyColumn {
        contacts.forEach { (initial, contactsForInitial) ->
            stickyHeader {
                Text(
                    text = initial.toString(),
                    modifier = Modifier
                        .fillMaxWidth()
                        .background(MaterialTheme.colorScheme.surface)
                        .padding(16.dp),
                    style = MaterialTheme.typography.titleMedium
                )
            }
            items(contactsForInitial) { contact ->
                ContactItem(contact)
            }
        }
    }
}
```

## Anti-Patterns

### Avoid Side Effects in Composition

Bad:

```kotlin
@Composable
fun BadExample(viewModel: ViewModel) {
    viewModel.loadData()  // Called on every recomposition!

    Text("Data loaded")
}
```

Good:

```kotlin
@Composable
fun GoodExample(viewModel: ViewModel) {
    LaunchedEffect(Unit) {
        viewModel.loadData()
    }

    Text("Data loaded")
}
```

### Don't Read State in Remember Block

Bad:

```kotlin
@Composable
fun BadCounter(initial: Int) {
    // Won't update when initial changes
    var count by remember { mutableStateOf(initial) }
}
```

Good:

```kotlin
@Composable
fun GoodCounter(initial: Int) {
    var count by remember(initial) { mutableStateOf(initial) }
}
```

### Avoid Heavy Computation During Composition

Bad:

```kotlin
@Composable
fun BadList(items: List<Item>) {
    // Runs on every recomposition
    val sorted = items.sortedBy { it.name }
    LazyColumn { /* ... */ }
}
```

Good:

```kotlin
@Composable
fun GoodList(items: List<Item>) {
    val sorted by remember(items) {
        derivedStateOf { items.sortedBy { it.name } }
    }
    LazyColumn { /* ... */ }
}
```

## Related Skills

- **android-architecture**: MVVM and clean architecture patterns
- **android-kotlin-coroutines**: Async operations in Compose

مجوز

مجوز اعلام‌شده: MIT

MIT License

Copyright (c) 2026 majiayu000

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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SOFTWARE.

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