Android Runtime Rules

Applies to: Kotlin/Java files in /valdi/src/valdi/android/ and related Android runtime code

Overview

The Valdi Android runtime bridges TypeScript/Valdi components to native Android views. It's implemented in Kotlin and C++ (via JNI).

Code Style

• 4-space indentation for Kotlin/Java
• Follow Kotlin coding conventions
• Use Kotlin features (data classes, extension functions, etc.)

Key Concepts

View Rendering

• Valdi components map to Android Views
• View recycling for performance
• Efficient view updates

Platform Bridge

• JNI bridge to C++ runtime
• Kotlin/Java to native code communication
• Performance-critical paths

Common Patterns

Bazel Android Targets

android_library(
    name = "valdi_android",
    srcs = glob(["**/*.kt", "**/*.java"]),
)

View Binding

• Custom view implementations
• Attribute binding for Valdi properties
• Event handling

Testing

# Run Android runtime tests
bazel test //valdi:test_java

# Run with coverage
bazel coverage //valdi:test_java

Test files are in /valdi/test/java/

Building

# Build Android runtime library
bazel build //valdi:valdi_android

# Test with hello world app
valdi install android
cd apps/helloworld
valdi install android

Platform-Specific Notes

1. API Level - Be mindful of minimum API level
2. Android NDK - C++ integration via NDK
3. Permissions - Handle runtime permissions appropriately
4. Lifecycle - Android Activity/Fragment lifecycle

Important

• Performance - View creation and updates are critical
• Memory - Be careful with leaks (Activity context)
• Threading - UI thread vs background threads
• Compatibility - Support multiple Android versions

More Information

• Runtime source: /valdi/src/valdi/android/
• Runtime tests: /valdi/test/java/
• Build config: /valdi/BUILD.bazel
• Framework docs: /AGENTS.md