camerax

This skill provides procedural guidance and standard patterns for building camera applications on Android, with a focus on CameraX, including its Camera2Interop utilities, and Media3 integrations.

Core workflows

Handling immutable API patterns

Various Android camera and media APIs, especially CameraX VideoCapture, use a fluent, immutable builder-like pattern where methods return a new instance. Failing to reassign these results in settings, such as audio, being ignored.

Pattern: Reassignment is required

// WRONG
run {
  val pending = recorder.prepareRecording(context, opts)
  pending.withAudioEnabled() // This returns a new instance which is ignored
  val active = pending.start(exec, listener)
}

// CORRECT
run {
  val pending = recorder.prepareRecording(context, opts)
      .withAudioEnabled() // Chaining works
  val active = pending.start(exec, listener)
}

// ALSO CORRECT
run {
  var pending = recorder.prepareRecording(context, opts)
  pending = pending.withAudioEnabled() // Reassignment
  val active = pending.start(exec, listener)
}

See immutability for a list of affected classes.

Migrating to CameraX

When migrating legacy camera codebases to the CameraX Jetpack library:

• Camera1 to CameraX : For migrating legacy android.hardware.Camera implementations, surface handling, and manual lifecycles, see the Camera1 migration guide.
• Camera2 to CameraX : For migrating more recent but verbose android.hardware.camera2 implementations, session state callbacks, and interop patterns, see the Camera2 migration guide.

Comprehensive feature blueprinting

For multi-step features that involve multiple files and hardware-level wiring, follow the Structural Blueprinting approach to avoid system timeouts. Such complex features include:

• Manual controls : Break down into the ViewModel state, the controller layer, and the Camera2Interop wiring in the session.
• RAW capture: Separate JPEG and RAW output configurations into discrete build steps.
• Custom effects : Prefer Media3Effect or SurfaceProcessor over manual OpenGL pipelines unless absolute performance is required.
• Low-light : See low-light for Night Mode and LLB guidance.
• Foldables : See foldables for handling dynamic postures and hinge states.
• XR, AR, and VR : See xr for spatial tracking, passthrough synchronization, and latency guardrails.
• Thermals and power : See thermals for managing StreamUseCase optimizations and PowerManager thermal states.
• Testing and mocking : See testing for using FakeCameraConfig, handling asynchronous lifecycles, and validating analysis pipelines.
• ML Kit spatial analysis : See mlkit-spatial for coordinate mapping, rotation logic, and mirrored lens handling.
• Wear OS camera remote : See wear-os for circular UI constraints, Data Layer API syncing, and remote trigger logic.