# Android Developer Markdown Brain
> Used by AI pipeline to plan, generate, and validate Android apps (Jetpack Compose, XML, SDK APIs).

---

## Project Structure (Compose)
```
app/
├── src/main/
│   ├── AndroidManifest.xml
│   ├── java/com/dolor3v/app/
│   │   ├── MainActivity.kt
│   │   ├── ui/
│   │   │   ├── theme/
│   │   │   │   ├── Color.kt
│   │   │   │   ├── Theme.kt
│   │   │   │   └── Type.kt
│   │   │   ├── screens/
│   │   │   │   ├── HomeScreen.kt
│   │   │   │   └── DetailScreen.kt
│   │   │   └── components/
│   │   ├── data/
│   │   │   ├── repository/
│   │   │   ├── model/
│   │   │   └── api/
│   │   ├── domain/
│   │   │   └── usecase/
│   │   └── di/
│   └── res/
│       ├── drawable/
│       ├── values/
│       │   ├── strings.xml
│       │   ├── colors.xml
│       │   └── themes.xml
│       └── mipmap/
├── build.gradle.kts
└── proguard-rules.pro

build.gradle.kts  (project level)
settings.gradle.kts
gradle/libs.versions.toml
```

---

## build.gradle.kts (App Level)
```kotlin
plugins {
    alias(libs.plugins.android.application)
    alias(libs.plugins.kotlin.android)
    alias(libs.plugins.kotlin.compose)
    alias(libs.plugins.hilt)
    id("kotlin-kapt")
}

android {
    namespace = "com.dolor3v.app"
    compileSdk = 35

    defaultConfig {
        applicationId = "com.dolor3v.app"
        minSdk = 26
        targetSdk = 35
        versionCode = 1
        versionName = "1.0.0"
        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            isMinifyEnabled = true
            isShrinkResources = true
            proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
            signingConfig = signingConfigs.getByName("release")
        }
        debug {
            applicationIdSuffix = ".debug"
            isDebuggable = true
        }
    }

    compileOptions {
        sourceCompatibility = JavaVersion.VERSION_17
        targetCompatibility = JavaVersion.VERSION_17
    }
    kotlinOptions { jvmTarget = "17" }

    buildFeatures {
        compose = true
        buildConfig = true
    }
}

dependencies {
    // Core
    implementation(libs.androidx.core.ktx)
    implementation(libs.androidx.lifecycle.runtime.ktx)
    implementation(libs.androidx.activity.compose)

    // Compose BOM
    implementation(platform(libs.androidx.compose.bom))
    implementation(libs.androidx.ui)
    implementation(libs.androidx.ui.graphics)
    implementation(libs.androidx.ui.tooling.preview)
    implementation(libs.androidx.material3)

    // Navigation
    implementation(libs.androidx.navigation.compose)

    // ViewModel
    implementation(libs.androidx.lifecycle.viewmodel.compose)

    // Hilt DI
    implementation(libs.hilt.android)
    kapt(libs.hilt.compiler)
    implementation(libs.androidx.hilt.navigation.compose)

    // Retrofit + OkHttp
    implementation(libs.retrofit)
    implementation(libs.retrofit.converter.gson)
    implementation(libs.okhttp.logging.interceptor)

    // Room
    implementation(libs.room.runtime)
    implementation(libs.room.ktx)
    kapt(libs.room.compiler)

    // Coil (images)
    implementation(libs.coil.compose)

    // DataStore
    implementation(libs.datastore.preferences)

    // Coroutines
    implementation(libs.kotlinx.coroutines.android)

    // Testing
    testImplementation(libs.junit)
    androidTestImplementation(libs.androidx.junit)
    androidTestImplementation(libs.androidx.espresso.core)
    androidTestImplementation(platform(libs.androidx.compose.bom))
    androidTestImplementation(libs.androidx.ui.test.junit4)
    debugImplementation(libs.androidx.ui.tooling)
}
```

---

## Jetpack Compose Patterns

### MainActivity
```kotlin
@AndroidEntryPoint
class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContent {
            MyAppTheme {
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colorScheme.background
                ) {
                    AppNavHost()
                }
            }
        }
    }
}
```

### Navigation
```kotlin
@Composable
fun AppNavHost(
    navController: NavHostController = rememberNavController(),
    startDestination: String = Screen.Home.route
) {
    NavHost(navController = navController, startDestination = startDestination) {
        composable(Screen.Home.route) {
            HomeScreen(navController = navController)
        }
        composable(
            route = Screen.Detail.route,
            arguments = listOf(navArgument("id") { type = NavType.IntType })
        ) { backStack ->
            val id = backStack.arguments?.getInt("id") ?: 0
            DetailScreen(id = id, navController = navController)
        }
    }
}

sealed class Screen(val route: String) {
    object Home   : Screen("home")
    object Detail : Screen("detail/{id}") {
        fun createRoute(id: Int) = "detail/$id"
    }
}
```

### ViewModel + StateFlow
```kotlin
@HiltViewModel
class HomeViewModel @Inject constructor(
    private val repository: PostRepository
) : ViewModel() {

    private val _uiState = MutableStateFlow<UiState<List<Post>>>(UiState.Loading)
    val uiState: StateFlow<UiState<List<Post>>> = _uiState.asStateFlow()

    init { loadPosts() }

    fun loadPosts() {
        viewModelScope.launch {
            _uiState.value = UiState.Loading
            repository.getPosts()
                .onSuccess { _uiState.value = UiState.Success(it) }
                .onFailure { _uiState.value = UiState.Error(it.message ?: "Unknown error") }
        }
    }
}

sealed class UiState<out T> {
    object Loading : UiState<Nothing>()
    data class Success<T>(val data: T) : UiState<T>()
    data class Error(val message: String) : UiState<Nothing>()
}
```

### Screen with State Handling
```kotlin
@Composable
fun HomeScreen(
    viewModel: HomeViewModel = hiltViewModel(),
    navController: NavController
) {
    val uiState by viewModel.uiState.collectAsStateWithLifecycle()

    Scaffold(
        topBar = {
            TopAppBar(title = { Text("Home") })
        }
    ) { padding ->
        Box(modifier = Modifier.padding(padding).fillMaxSize()) {
            when (val state = uiState) {
                is UiState.Loading -> CircularProgressIndicator(Modifier.align(Alignment.Center))
                is UiState.Error   -> Text(state.message, color = MaterialTheme.colorScheme.error)
                is UiState.Success -> PostList(posts = state.data, onPostClick = { id ->
                    navController.navigate(Screen.Detail.createRoute(id))
                })
            }
        }
    }
}
```

### LazyColumn (RecyclerView equivalent)
```kotlin
@Composable
fun PostList(posts: List<Post>, onPostClick: (Int) -> Unit) {
    LazyColumn(
        contentPadding = PaddingValues(16.dp),
        verticalArrangement = Arrangement.spacedBy(8.dp)
    ) {
        items(posts, key = { it.id }) { post ->
            PostCard(post = post, onClick = { onPostClick(post.id) })
        }
    }
}

@Composable
fun PostCard(post: Post, onClick: () -> Unit) {
    Card(
        onClick = onClick,
        modifier = Modifier.fillMaxWidth(),
        elevation = CardDefaults.cardElevation(defaultElevation = 2.dp)
    ) {
        Column(modifier = Modifier.padding(16.dp)) {
            Text(post.title, style = MaterialTheme.typography.titleMedium)
            Spacer(Modifier.height(4.dp))
            Text(post.excerpt, style = MaterialTheme.typography.bodySmall,
                color = MaterialTheme.colorScheme.onSurfaceVariant,
                maxLines = 2, overflow = TextOverflow.Ellipsis)
        }
    }
}
```

---

## Room Database

### Entity
```kotlin
@Entity(tableName = "posts")
data class PostEntity(
    @PrimaryKey val id: Int,
    @ColumnInfo(name = "title") val title: String,
    @ColumnInfo(name = "content") val content: String,
    @ColumnInfo(name = "created_at") val createdAt: Long = System.currentTimeMillis()
)
```

### DAO
```kotlin
@Dao
interface PostDao {
    @Query("SELECT * FROM posts ORDER BY created_at DESC")
    fun getAllPosts(): Flow<List<PostEntity>>

    @Query("SELECT * FROM posts WHERE id = :id")
    suspend fun getPostById(id: Int): PostEntity?

    @Insert(onConflict = OnConflictStrategy.REPLACE)
    suspend fun insertPosts(posts: List<PostEntity>)

    @Delete
    suspend fun deletePost(post: PostEntity)

    @Query("DELETE FROM posts")
    suspend fun clearAll()
}
```

### Database
```kotlin
@Database(entities = [PostEntity::class], version = 1, exportSchema = true)
@TypeConverters(Converters::class)
abstract class AppDatabase : RoomDatabase() {
    abstract fun postDao(): PostDao

    companion object {
        @Volatile private var INSTANCE: AppDatabase? = null

        fun getInstance(context: Context): AppDatabase =
            INSTANCE ?: synchronized(this) {
                Room.databaseBuilder(context, AppDatabase::class.java, "app.db")
                    .fallbackToDestructiveMigration()
                    .build().also { INSTANCE = it }
            }
    }
}
```

---

## Retrofit API Service
```kotlin
interface ApiService {
    @GET("posts")
    suspend fun getPosts(
        @Query("page") page: Int = 1,
        @Query("per_page") perPage: Int = 20
    ): Response<List<PostDto>>

    @GET("posts/{id}")
    suspend fun getPost(@Path("id") id: Int): Response<PostDto>

    @POST("posts")
    suspend fun createPost(@Body post: CreatePostDto): Response<PostDto>

    @Multipart
    @POST("media")
    suspend fun uploadMedia(
        @Part file: MultipartBody.Part,
        @Part("title") title: RequestBody
    ): Response<MediaDto>
}

// Retrofit instance
@Provides @Singleton
fun provideRetrofit(): Retrofit = Retrofit.Builder()
    .baseUrl(BuildConfig.API_BASE_URL)
    .addConverterFactory(GsonConverterFactory.create())
    .client(
        OkHttpClient.Builder()
            .addInterceptor(HttpLoggingInterceptor().apply {
                level = HttpLoggingInterceptor.Level.BODY
            })
            .addInterceptor { chain ->
                chain.proceed(
                    chain.request().newBuilder()
                        .addHeader("Authorization", "Bearer ${BuildConfig.API_TOKEN}")
                        .build()
                )
            }
            .connectTimeout(30, TimeUnit.SECONDS)
            .readTimeout(30, TimeUnit.SECONDS)
            .build()
    )
    .build()
```

---

## AndroidManifest.xml
```xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android">

    <!-- Permissions -->
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.READ_MEDIA_IMAGES" />
    <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />

    <application
        android:name=".MyApplication"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.MyApp"
        android:usesCleartextTraffic="false">

        <activity
            android:name=".MainActivity"
            android:exported="true"
            android:windowSoftInputMode="adjustResize">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <!-- Deep links -->
        <activity android:name=".DeepLinkActivity">
            <intent-filter android:autoVerify="true">
                <action android:name="android.intent.action.VIEW" />
                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.BROWSABLE" />
                <data android:scheme="https" android:host="dolor3v.com" />
            </intent-filter>
        </activity>

        <!-- FCM -->
        <service android:name=".service.MyFirebaseMessagingService"
            android:exported="false">
            <intent-filter>
                <action android:name="com.google.firebase.MESSAGING_EVENT" />
            </intent-filter>
        </service>
    </application>
</manifest>
```

---

## Material 3 Theme
```kotlin
// Color.kt
val BlueElectric   = Color(0xFF3B82F6)
val AmberSpark     = Color(0xFFF59E0B)
val DeepSpace      = Color(0xFF090E1A)
val SpaceSurface   = Color(0xFF0F1629)

private val DarkColorScheme = darkColorScheme(
    primary       = BlueElectric,
    secondary     = AmberSpark,
    background    = DeepSpace,
    surface       = SpaceSurface,
    onPrimary     = Color.White,
    onBackground  = Color(0xFFE2E8F0),
    onSurface     = Color(0xFF94A3B8),
)

@Composable
fun MyAppTheme(darkTheme: Boolean = isSystemInDarkTheme(), content: @Composable () -> Unit) {
    val colorScheme = if (darkTheme) DarkColorScheme else LightColorScheme
    MaterialTheme(colorScheme = colorScheme, typography = Typography, content = content)
}
```