Basic Layouts in Jetpack Compose (MySoothe)

A polished implementation of Google's "Basic Layouts in Compose" codelab showcasing the MySoothe wellness app with adaptive layouts, custom slot APIs, LazyRows, LazyHorizontalGrids, and dynamic NavigationRail/BottomNavigation.

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📖 Overview

The Compose-BasicLayoutsCodelab project is an idiomatic demonstration of modern declarative UI engineering using Jetpack Compose and Material Design 3. Built upon Google's reference design for the MySoothe holistic wellness application, this repository illustrates how to translate complex UI mocks into modular, testable, and adaptive Compose components.

🎯 Educational & Architectural Objectives

• Declarative Layout Composition: Transition from legacy View hierarchies to composable layout primitives (Row, Column, Box, Surface).
• Slot API Architecture: Implement reusable container composables (HomeSection) leveraging trailing lambda slot patterns.
• Performant Lazy Collections: Handle horizontal scrolling lists (LazyRow) and multi-row horizontal grids (LazyHorizontalGrid) with efficient recycling.
• Adaptive Form Factors: Dynamically switch between Portrait (Bottom Navigation Bar) and Landscape / Tablet (Navigation Rail) based on WindowSizeClass.
• Material 3 Theming & Typography: Utilize custom color schemes, shapes, and font families (Kulim Park and Lato) with baseline padding precision.

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🏗️ Architecture & Component Flow

graph TD
classDef comp fill:#2D3748,stroke:#4FD1C5,stroke-width:2px,color:#fff;
classDef state fill:#1A365D,stroke:#63B3ED,stroke-width:2px,color:#fff;
classDef ui fill:#234E52,stroke:#38B2AC,stroke-width:2px,color:#fff;
MainActivity["MainActivity<br/>(calculateWindowSizeClass)"]:::state --> WindowDecision{"WindowWidthSizeClass"}
WindowDecision -->|Compact (Portrait)| PortraitApp["MySootheAppPortrait()"]:::comp
WindowDecision -->|Medium / Expanded (Landscape)| LandscapeApp["MySootheAppLandscape()"]:::comp
PortraitApp --> ScaffoldUI["Scaffold(bottomBar = SootheBottomNavigation)"]:::ui
ScaffoldUI --> HomeScreenP["HomeScreen(Modifier.verticalScroll)"]:::ui
LandscapeApp --> RowUI["Row { SootheNavigationRail(), HomeScreen() }"]:::ui
RowUI --> HomeScreenL["HomeScreen(Modifier.verticalScroll)"]:::ui
HomeScreenP --> SearchBar["SearchBar (TextField + Icons.Default.Search)"]:::comp
HomeScreenP --> Section1["HomeSection('Align your body')"]:::comp
HomeScreenP --> Section2["HomeSection('Favorite collections')"]:::comp
Section1 --> LazyRowUI["LazyRow -> AlignYourBodyElement(Image + Baseline Text)"]:::ui
Section2 --> LazyGridUI["LazyHorizontalGrid (2 Fixed Rows) -> FavoriteCollectionCard"]:::ui

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✨ Core Concepts & Patterns Demonstrated

1. Adaptive Screen Form Factors

Using androidx.compose.material3.windowsizeclass.WindowSizeClass, the app detects device orientation and window width dynamically:

• Compact Width (Phone Portrait): Renders a Scaffold hosting a SootheBottomNavigation (NavigationBar & NavigationBarItem).
• Medium / Expanded Width (Phone Landscape, Foldable, Tablet): Renders a split Row hosting a persistent SootheNavigationRail (NavigationRail & NavigationRailItem).

@Composable
funMySootheApp(windowSize:WindowSizeClass) {
when (windowSize.widthSizeClass) {
WindowWidthSizeClass.Compact->MySootheAppPortrait()
WindowWidthSizeClass.Medium, WindowWidthSizeClass.Expanded->MySootheAppLandscape()
else->MySootheAppPortrait()
}
}

2. Slot API Pattern (HomeSection)

Modular container component decoupling section header typography and baseline padding from nested child composables:

@Composable
funHomeSection(
@StringRes title:Int,
modifier:Modifier = Modifier,
content: @Composable () ->Unit
) {
Column(modifier = modifier) {
Text(
text = stringResource(title),
style =MaterialTheme.typography.titleMedium,
modifier =Modifier
.paddingFromBaseline(top =40.dp, bottom =16.dp)
.padding(horizontal =16.dp)
)
content()
}
}

3. Circular Cropped Elements & Baseline Spacing

AlignYourBodyElement uses Modifier.clip(CircleShape) and ContentScale.Crop paired with paddingFromBaseline to adhere strictly to Material Design typographic spacing rules.

4. Dual-Row Horizontal Lazy Grid

LazyHorizontalGrid with GridCells.Fixed(2) displays curated wellness cards with balanced horizontal and vertical spacing (spacedBy(16.dp)).

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📱 Key Components & Project Structure

Compose-BasicLayoutsCodelab/
├── app/
│ ├── src/main/java/com/codelab/basiclayouts/
│ │ ├── MainActivity.kt # Primary Activity, Layout Composables & Previews
│ │ └── ui/theme/
│ │ ├── Color.kt # Taupe & Sand Material 3 color palettes
│ │ ├── Shape.kt # Corner radius & surface geometry
│ │ ├── Theme.kt # MySootheTheme dark/light configuration
│ │ └── Type.kt # Typography using Kulim Park & Lato fonts
│ ├── src/main/res/
│ │ ├── drawable/ # Body alignment & meditation asset images
│ │ ├── font/ # TTF font files (Kulim Park, Lato)
│ │ └── values/ # Color definitions and localized strings
│ └── build.gradle # Gradle dependencies, Compose BOM & plugins

Composable Function Index

Composable	Description	Key Modifiers / APIs Used
SearchBar	Search input bar with lead icon	TextField, heightIn(min = 56.dp), fillMaxWidth
AlignYourBodyElement	Circular wellness category card	Image, clip(CircleShape), paddingFromBaseline
AlignYourBodyRow	Horizontally scrollable category list	LazyRow, Arrangement.spacedBy(8.dp)
FavoriteCollectionCard	Rounded card with image + title	Surface(shape = medium), Row, size(80.dp)
FavoriteCollectionsGrid	Two-row horizontal grid of collections	LazyHorizontalGrid, GridCells.Fixed(2)
HomeSection	Slot-based section container	Slot API (content: @Composable () -> Unit)
HomeScreen	Full vertical scrollable dashboard	Column(Modifier.verticalScroll(rememberScrollState()))
SootheBottomNavigation	Material 3 bottom app navigation bar	NavigationBar, NavigationBarItem
SootheNavigationRail	Material 3 vertical side rail	NavigationRail, NavigationRailItem
MySootheApp	Responsive root entry point	WindowSizeClass, calculateWindowSizeClass

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🛠️ Technology Stack Matrix

Layer / Category	Technology / Library	Version / Details
Language	Kotlin	2.0+
UI Framework	Jetpack Compose	BOM 2025.02.00
Design System	Material Design 3	androidx.compose.material3:material3
Adaptive Layouts	Material 3 Window Size Class	material3-window-size-class:1.3.1
Iconography	Material Icons Extended	material-icons-extended
Architecture	Declarative Slot APIs	Slot pattern & stateless composables
Build System	Gradle (Kotlin DSL / Groovy)	AGP 8.8+, Target SDK 33, Compile SDK 35
Testing	Compose UI Test & JUnit4	androidx.compose.ui:ui-test-junit4

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🚀 Getting Started

Prerequisites

• Android Studio Ladybug (2024.2.1+) or newer.
• Android SDK 35 with Build-Tools installed.
• JDK 17 or JDK 21.

Build & Run

1. Clone repository:

   git clone https://github.com/shayann07/Compose-BasicLayoutsCodelab.git
   cd Compose-BasicLayoutsCodelab

2. Open in Android Studio: Select File > Open... and choose the project directory.
3. Gradle Sync: Allow Android Studio to sync dependencies and the Compose BOM.
4. Deploy: Select an Android Virtual Device (AVD) or physical device running Android 6.0 (API 23) or higher and click Run (Shift + F10).
5. Interactive Previews: Open MainActivity.kt and toggle Split / Design mode to preview individual components and multi-device layouts (MySoothePortraitPreview & MySootheLandscapePreview).

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📄 License

This project is licensed under the Apache License 2.0 — based on Google's Jetpack Compose Codelab sample code.