mobile-android-design

SKILL.md

Android Mobile Design

Master Material Design 3 (Material You) and Jetpack Compose to build modern, adaptive Android applications that integrate seamlessly with the Android ecosystem.

When to Use This Skill

Designing Android app interfaces following Material Design 3

Building Jetpack Compose UI and layouts

Implementing Android navigation patterns (Navigation Compose)

Creating adaptive layouts for phones, tablets, and foldables

Using Material 3 theming with dynamic colors

Building accessible Android interfaces

Implementing Android-specific gestures and interactions

Designing for different screen configurations

Detailed section: Core Concepts

Originally a 9201-byte section in this SKILL.md. Moved to references/details.md to fit Codex's 8 KB skill body cap.
Quick Start Component

@Composable
fun ItemListCard(
    item: Item,
    onItemClick: () -> Unit,
    modifier: Modifier = Modifier
) {
    Card(
        onClick = onItemClick,
        modifier = modifier.fillMaxWidth(),
        shape = RoundedCornerShape(12.dp)
    ) {
        Row(
            modifier = Modifier
                .padding(16.dp)
                .fillMaxWidth(),
            verticalAlignment = Alignment.CenterVertically
        ) {
            Box(
                modifier = Modifier
                    .size(48.dp)
                    .clip(CircleShape)
                    .background(MaterialTheme.colorScheme.primaryContainer),
                contentAlignment = Alignment.Center
            ) {
                Icon(
                    imageVector = Icons.Default.Star,
                    contentDescription = null,
                    tint = MaterialTheme.colorScheme.onPrimaryContainer
                )
            }

            Spacer(modifier = Modifier.width(16.dp))

            Column(modifier = Modifier.weight(1f)) {
                Text(
                    text = item.title,
                    style = MaterialTheme.typography.titleMedium
                )
                Text(
                    text = item.subtitle,
                    style = MaterialTheme.typography.bodyMedium,
                    color = MaterialTheme.colorScheme.onSurfaceVariant
                )
            }

            Icon(
                imageVector = Icons.Default.ChevronRight,
                contentDescription = null,
                tint = MaterialTheme.colorScheme.onSurfaceVariant
            )
        }
    }
}

Best Practices

Use Material Theme: Access colors via MaterialTheme.colorScheme for automatic dark mode support

Support Dynamic Color: Enable dynamic color on Android 12+ for personalization

Adaptive Layouts: Use WindowSizeClass for responsive designs

Content Descriptions: Add contentDescription to all interactive elements

Touch Targets: Minimum 48dp touch targets for accessibility

State Hoisting: Hoist state to make components reusable and testable

Remember Properly: Use remember and rememberSaveable appropriately

Preview Annotations: Add @Preview with different configurations

Common Issues

Recomposition Issues: Avoid passing unstable lambdas; use remember

State Loss: Use rememberSaveable for configuration changes

Performance: Use LazyColumn instead of Column for long lists

Theme Leaks: Ensure MaterialTheme wraps all composables

Navigation Crashes: Handle back press and deep links properly

Memory Leaks: Cancel coroutines in DisposableEffect