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πŸš€ Jetpack Compose Migration for Camera Samples (Video, Extensions, MLKit)

πŸ“ Description

This pull request continues our initiative to modernize the camera-samples repository by converting existing XML View-based examples to Jetpack Compose.

In this 2nd iteration, 3 key samples has been successfully migrated from their original implementations in the android/camera-samples repository. The migration involved:

  • Re-architecting the UI layer entirely in Jetpack Compose from XML Android Views.
  • Simplifying the underlying logic where appropriate, leveraging Compose's declarative paradigm.
  • Ensuring the sample is fully implemented using Jetpack Compose, providing cleaner and more maintainable examples.

βœ… How Has This Been Tested?

Manual testing has been performed on the following configuration to ensure the core functionality of the migrated samples remains intact:

Test Configuration #1

  • Device: Google Pixel 9 Pro XL (Physical)
  • Android Version: API 35 (Android 15 Upside Down Cake)
  • Key Scenarios Validated:
    • Successful app launch and UI rendering
    • Camera permission request and handling.
    • Core sample functionality (e.g., image capture, tap-to-focus).
    • Basic navigation and state handling within the Compose UI.

Next Steps:

@madebymozart madebymozart self-assigned this Jun 16, 2025
@madebymozart madebymozart added the enhancement New feature or request label Jun 16, 2025
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Summary of Changes

Hello @madebymozart, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request is the second phase of modernizing the camera-samples repository by converting more CameraX examples to Jetpack Compose. It focuses on migrating the Video, Extensions, and MLKit samples, providing fully Compose-based implementations that leverage declarative UI and simplified logic compared to their original XML counterparts.

Highlights

  • Compose Migration: Migrated three key CameraX samples (Video, Extensions, and MLKit) from XML Views to Jetpack Compose, modernizing their UI and underlying logic.
  • CameraX Extensions Sample: Introduced a new Compose sample demonstrating how to use CameraX Extensions (like Bokeh, HDR, Night) and switch between available extensions and camera lenses.
  • CameraX MLKit Sample: Introduced a new Compose sample showcasing integration between CameraX and MLKit for real-time QR code detection in the camera feed, including drawing bounding boxes and handling interactions.
  • CameraX Video Sample: Introduced a new Compose sample for basic video capture using CameraX, including handling recording state, saving video to MediaStore, and providing a simple playback screen.
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Code Review

This pull request successfully migrates three CameraX samples (Video, Extensions, MLKit) to Jetpack Compose. The changes involve re-architecting the UI layer, simplifying logic using Compose's declarative paradigm, and ensuring full Compose implementation. The code is generally well-structured and follows modern Android development practices.

I've identified a few areas for improvement, primarily related to resource management in the MLKit sample, potential null pointer exceptions, and an unused/buggy executor in the Video sample. These suggestions aim to enhance robustness and clarity.

Comment on lines 68 to 74
var barcodeScanner = remember {
BarcodeScanning.getClient(
BarcodeScannerOptions.Builder()
.setBarcodeFormats(Barcode.FORMAT_QR_CODE)
.build(),
)
}
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medium

BarcodeScanner implements java.io.Closeable. It's important to close it when it's no longer needed to free up resources. Consider using DisposableEffect to close the scanner when the composable leaves the composition.

Comment on lines +250 to +251
val localCameraExecutor =
remember { Executors.newSingleThreadExecutor() } // Or pass from parent
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medium

The localCameraExecutor initialized here appears to be unused for CameraX binding operations, as ProcessCameraProvider.addListener uses ContextCompat.getMainExecutor(context) and bindToLifecycle manages its own threading. This executor might be redundant.

Comment on lines +310 to +314
DisposableEffect(Unit) {
onDispose {
localCameraExecutor.isShutdown.not()
}
}
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medium

The onDispose block for localCameraExecutor currently contains localCameraExecutor.isShutdown.not(), which evaluates to a boolean but doesn't perform any action. If the intention was to shut down the executor, it should be localCameraExecutor.shutdown(). However, as noted in another comment, this executor might be unnecessary.

    DisposableEffect(Unit) {
        onDispose {
            // If localCameraExecutor is deemed necessary and needs cleanup:
            // localCameraExecutor.shutdown()
        }
    }

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@madebymozart Any reason it's localCameraExecutor.isShutdown.not(), but not localCameraExecutor.shutdown()? Gemini's review looks reasonable to me.

madebymozart and others added 2 commits June 16, 2025 15:46
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
@madebymozart madebymozart enabled auto-merge (squash) August 26, 2025 16:32
@madebymozart madebymozart requested review from donovanfm and removed request for MagicalMeghan August 26, 2025 16:32
- Update imports in CameraExtensionsViewModel.kt and QrCodeDrawable.kt.
- Change `barcodeScanner` from `var` to `val` in CameraXMlKitSample.kt.
- Update Log tag in CameraXMlKitSample.kt.
* As is, this class only handles displaying the QR Code data if it's a URL. Other data types
* can be handled by adding more cases of Barcode.TYPE_URL in the init block.
*/
class QrCodeViewModel(barcode: Barcode) {
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I'm not sure overall if this class name is adapted as it doesn't follow the usual logic of a view model on Android and a reference to the context shouldn't be extracted from the event listener but CameraX/MLKit API constraints make it hard to follow the Android way...

@madebymozart madebymozart merged commit c452fac into main Aug 29, 2025
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4 participants