如何在 PreviewView 中使用 CameraX？

Question

我不知道如何在预览视图中使用 camerax。

Answer 1

Here is an example of how to use Camerax with PreviewView , the code uses the latest versions of CameraX, meaning camera-camera2 version 1.1.0-alpha08, and camera-view version 1.0.0-alpha28.

@Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        previewView = view.findViewById(R.id.preview_view);
  

        setCameraProviderListener();

    }

private void setCameraProviderListener() {
        ListenableFuture<ProcessCameraProvider> cameraProviderFuture =
                ProcessCameraProvider.getInstance(requireContext());
        cameraProviderFuture.addListener(() -> {

            try {
                ProcessCameraProvider cameraProvider = cameraProviderFuture.get();
                bindPreview(cameraProvider);
            } catch (ExecutionException | InterruptedException e) {
                // No errors need to be handled for this Future
                // This should never be reached
                e.printStackTrace();
            }
        }, ContextCompat.getMainExecutor(requireContext()));
    }

 private void bindPreview(ProcessCameraProvider cameraProvider) {
        
 previewView.setPreferredImplementationMode(PreviewView.ImplementationMode.SURFACE_VIEW);

        Preview preview = new Preview.Builder().setTargetAspectRatio(AspectRatio.RATIO_4_3).
                setTargetRotation(previewView.getDisplay().getRotation())
                .build();


        CameraSelector cameraSelector =
                new CameraSelector.Builder().requireLensFacing(CameraSelector.LENS_FACING_BACK).build();

        preview.setSurfaceProvider(previewView.getSurfaceProvider());

   UseCaseGroup useCaseGroup = new UseCaseGroup.Builder()
                .addUseCase(preview)
                .addUseCase(imageCapture)//use this case if you want take picture or videoCapture for videoRecording
                .build();


        cameraProvider.bindToLifecycle(this, cameraSelector,preview);

    }

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.camera.view.PreviewView
        android:id="@+id/preview_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/Yellow"
        android:layout_gravity="center" />

</LinearLayout>

Answer 2

Here is an article that explains PreviewView and how to use it. It's valid up to version 1.0.0-alpha10 of camera-view, I'll try to keep it up to date.

Answer 3

I had set android:hardwareAccelerated="false" while debugging a different error, and had forgotten to remove it (or set it to true ). I quickly noticed camera functionality had stopped working.

Make sure there is no android:hardwareAccelerated="false" in your apps manifest. If there is, either remove it, or set it to true . If this is set to false it will affect the camera preview stream.

TL;DR

Remove any android:hardwareAccelerated="false" in your manifest, or set it true .