Android UI Design Guide

Overview

Build native Android interfaces that follow Material Design 3 (Material You) by applying systematic design principles. This skill provides comprehensive guidelines for Jetpack Compose-first development with Dynamic Color, spacing, typography, and component-specific patterns optimized for Android.

When to Use This Skill

Activate this skill when:

• Building Android UI with Jetpack Compose or XML
• Creating Android app screens, layouts, or components
• Working with Android development (Kotlin, Compose, Android Studio)
• Receiving requests like:
  • "Create a login screen in Compose"
  • "Design an Android settings view"
  • "Build a card layout for Android"
  • "Make this Android UI follow Material Design"
  • "Style this Compose screen"

Do NOT activate for:

• Web development
• iOS development
• Backend/server code
• Non-visual Android tasks

Core Design Philosophy

Follow Material Design 3 principles + Flexible extensions:

Material Design 3 Principles

1. Expressive - Dynamic Color from user wallpaper, personalized theming
2. Adaptive - Responsive layouts for phones, tablets, foldables
3. Cohesive - Consistent Material components and interactions

Flexible Extensions

4. Simplicity - Remove unnecessary elements, focus on core features
5. Accessibility - 48x48dp touch targets, WCAG AA compliance, TalkBack support

Framework Priorities

• Primary: Jetpack Compose (declarative, modern, recommended)
• Secondary: XML Views (legacy support)

How to Use This Skill

Step 1: Load Relevant Reference

Read references/design-principles.md - Material Design 3 principles
Read references/color-system.md - Dynamic Color, Material Theme
Read references/spacing-system.md - 4dp grid, touch targets
Read references/typography.md - Roboto, Material Type Scale
Read references/component-patterns.md - Compose component best practices
Read references/anti-patterns.md - Common Android design mistakes

Step 2: Apply Component-Specific Patterns

• Button: component-patterns.md → Button section
• Card: component-patterns.md → Card section
• List: component-patterns.md → LazyColumn section
• TextField: component-patterns.md → TextField section
• Navigation: component-patterns.md → Navigation section
• Dialog: component-patterns.md → AlertDialog section

Step 3: Validate Against Anti-Patterns

• ❌ Hardcoded colors (no Dark Mode)
• ❌ Material Theme ignored
• ❌ Touch targets smaller than 48x48dp
• ❌ Fixed text sizes (no Type Scale)
• ❌ 4dp grid violations
• ❌ Nested scrolling

Step 4: Ensure System Consistency

4dp grid system:

• Use only: 4dp, 8dp, 12dp, 16dp, 24dp, 32dp, 48dp, 64dp
• Compose: 16.dp, .padding(16.dp)

Material Theme colors:

• Labels: colorScheme.onSurface, colorScheme.onSurfaceVariant
• Backgrounds: colorScheme.surface, colorScheme.surfaceVariant
• Primary actions: colorScheme.primary
• Dynamic Color support (Android 12+)

Material Type Scale (REQUIRED):

• Display: displayLarge, displayMedium, displaySmall
• Headline: headlineLarge, headlineMedium, headlineSmall
• Title: titleLarge, titleMedium, titleSmall
• Body: bodyLarge, bodyMedium, bodySmall
• Label: labelLarge, labelMedium, labelSmall

Resources

references/

• design-principles.md - Material Design 3 principles (Expressive, Adaptive, Cohesive)
• color-system.md - Dynamic Color, Material Theme, dark mode
• spacing-system.md - 4dp grid, touch targets, Compose modifiers
• typography.md - Roboto, Material Type Scale, font weights
• component-patterns.md - Compose patterns for Button, Card, List, TextField, Navigation, Dialog
• anti-patterns.md - Common mistakes: hardcoded colors, touch targets, Material Theme neglect

Quick Decision Tree

Android UI Component Request
│
├─ What component? → Load component-patterns.md section
│
├─ What spacing? → Use 4dp grid (spacing-system.md)
│
├─ What colors? → Material Theme + Dynamic Color (color-system.md)
│
├─ What typography? → Material Type Scale (typography.md)
│
├─ Compose or XML? → Compose first
│
└─ Validation → Check anti-patterns.md

Examples

Good Request Flow:

User: "Create a login form in Compose"
→ Read references/component-patterns.md (TextField section)
→ Apply: OutlinedTextField, Material Type Scale, 4dp spacing
→ Validate against anti-patterns.md
→ Implement with Column { OutlinedTextField, Button }

Component Implementation Checklist:

• ✅ Spacing uses 4dp multiples
• ✅ Material Type Scale used (bodyMedium, titleLarge, etc.)
• ✅ Material Theme colors (auto Dark Mode)
• ✅ Touch targets minimum 48x48dp
• ✅ Material components used
• ✅ Dynamic Color support
• ✅ Accessibility (TalkBack contentDescription)

Compose Code Examples

✅ Good: Material-Compliant Button

Button(onClick = { }) {
    Text("확인")
}

✅ Good: Material Theme Colors

Card {
    Column(modifier = Modifier.padding(16.dp)) {
        Text(
            text = "제목",
            style = MaterialTheme.typography.titleLarge,
            color = MaterialTheme.colorScheme.onSurface
        )
        Text(
            text = "내용",
            style = MaterialTheme.typography.bodyMedium,
            color = MaterialTheme.colorScheme.onSurfaceVariant
        )
    }
}

❌ Bad: Hardcoded Colors, No Type Scale

Text(
    text = "제목",
    fontSize = 24.sp,  // ❌ No Type Scale
    color = Color.Black  // ❌ No Dark Mode
)

Platform-Specific Considerations

Dynamic Color (Android 12+)

val colorScheme = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
    dynamicLightColorScheme(LocalContext.current)
} else {
    lightColorScheme()
}

Dark Mode (REQUIRED)

• Test both light and dark themes
• Use Material Theme colors
• Never hardcode Color.Black, Color.White

Touch Targets

• Minimum 48x48dp for all interactive elements

Reference Documentation

• Material Design 3
• Jetpack Compose
• Material Theme Builder