如何冻结/锁定android Camera X预览与闪光灯更新拍照？

dependencies {
    def camerax_version = "1.1.0-alpha07"
    implementation "androidx.camera:camera-camera2:$camerax_version"
    implementation "androidx.camera:camera-lifecycle:$camerax_version"
    implementation "androidx.camera:camera-view:1.0.0-alpha23"
}

<androidx.camera.view.PreviewView
    android:id="@+id/previewView"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

val previewView: PreviewView = findViewById(R.id.previewView)
val preview: Preview = Preview.Builder().build()
val cameraSelector: CameraSelector = CameraSelector.Builder()
    .requireLensFacing(CameraSelector.LENS_FACING_BACK)
    .build()
val cameraProviderFuture: ListenableFuture<ProcessCameraProvider> = ProcessCameraProvider.getInstance(this)

cameraProviderFuture.addListener(Runnable {
    val cameraProvider: ProcessCameraProvider = cameraProviderFuture.get()
    cameraProvider.unbindAll()
    val camera: Camera = cameraProvider.bindToLifecycle(this, cameraSelector, preview)
    preview.setSurfaceProvider(previewView.createSurfaceProvider(camera.cameraInfo))
}, ContextCompat.getMainExecutor(this))

val imageCapture: ImageCapture = ImageCapture.Builder().build()

val outputFile = File(externalMediaDirs.first(), "photo.jpg")
val outputOptions = ImageCapture.OutputFileOptions.Builder(outputFile).build()
imageCapture.takePicture(outputOptions, ContextCompat.getMainExecutor(this), object : ImageCapture.OnImageSavedCallback {
    override fun onImageSaved(outputFileResults: ImageCapture.OutputFileResults) {
        // 图片保存成功后的处理
    }

    override fun onError(exception: ImageCaptureException) {
        // 拍照出错的处理
    }
})

cameraProvider.unbindAll()

cameraProvider.bindToLifecycle(this, cameraSelector, preview)