我在CameraX上使用PreviewView有一个问题？

问题描述

即使我将AspectRatio从AspectRatio.RATIO_16_9更改为AspectRatio.RATIO_4_3，PreviewView也会缩小到屏幕的一半！

@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.createSurfaceProvider());

        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>

这是我的代码，我面对这个问题已经两个月了！！ PreviewView包裹在LinearLayout中，黄色为background颜色，但是当相机启动时，它仅显示在PreviewView和{{1 }}变黑。

解决方法

最后，我发现答案有点棘手

android:hardwareAccelerated="true"

,

下面是我编写的用于测试您描述的问题的代码段，但我无法复制。

override fun onViewCreated(view: View,savedInstanceState: Bundle?) {
    super.onViewCreated(view,savedInstanceState)

    val cameraProviderFuture = ProcessCameraProvider.getInstance(requireContext())
        cameraProviderFuture.addListener(Runnable {
        val cameraProvider = cameraProviderFuture.get()
        bindPreview(cameraProvider,unbindAll = false)
        previewView.setOnClickListener {
            bindPreview(cameraProvider)
        }
    },ContextCompat.getMainExecutor(requireContext()))
}

private var aspectRatio = AspectRatio.RATIO_4_3
private fun getAndUpdateAspectRatio(): Int {
    val currentAspectRation = aspectRatio
    aspectRatio = if (aspectRatio == AspectRatio.RATIO_4_3) {
        AspectRatio.RATIO_16_9
    } else {
        AspectRatio.RATIO_4_3
    }
    return currentAspectRation
}

private fun bindPreview(cameraProvider: ProcessCameraProvider,unbindAll: Boolean = true) {
    val preview = Preview.Builder()
            .setTargetAspectRatio(getAndUpdateAspectRatio())
            .setTargetRotation(previewView.display.rotation)
            .build()

    previewView.preferredImplementationMode = PreviewView.ImplementationMode.SURFACE_VIEW
    preview.setSurfaceProvider(previewView.createSurfaceProvider())

    if (unbindAll) {
        cameraProvider.unbindAll()
    }
    cameraProvider.bindToLifecycle(viewLifecycleOwner,CameraSelector.DEFAULT_BACK_CAMERA,preview)
}

此代码位于Fragment内部，其布局包含用PreviewView包裹的LinearLayout。我在Pixel 3 XL和Nokia 1上进行了测试。能否测试一下，看看它在您的设备上是否失败？

此外，代码使用CameraX的最新版本，即camera-camera2版本1.0.0-beta07和camera-view版本1.0.0-alpha14。