如何使用cameraX在摄像头应用中实现FlashToggle按钮？

implementation 'androidx.camera:camera-camera2:1.1.0-alpha07'
implementation 'androidx.camera:camera-lifecycle:1.1.0-alpha07'
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 cameraProviderFuture = ProcessCameraProvider.getInstance(this)

cameraProviderFuture.addListener({
    val cameraProvider: ProcessCameraProvider = cameraProviderFuture.get()

    val preview = Preview.Builder().build().also {
        it.setSurfaceProvider(previewView.surfaceProvider)
    }

    val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA

    try {
        cameraProvider.unbindAll()
        cameraProvider.bindToLifecycle(this, cameraSelector, preview)
    } catch (e: Exception) {
        Log.e(TAG, "Error binding camera", e)
    }
}, ContextCompat.getMainExecutor(this))

<ToggleButton
    android:id="@+id/flashToggle"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textOff="Flash Off"
    android:textOn="Flash On" />

val flashToggle: ToggleButton = findViewById(R.id.flashToggle)

flashToggle.setOnCheckedChangeListener { _, isChecked ->
    val cameraControl = cameraProvider.get().cameraControl
    val cameraInfo = cameraProvider.get().cameraInfo

    if (cameraInfo.hasFlashUnit()) {
        cameraControl.enableTorch(isChecked)
    }
}