在Android上添加叠加层到相机实时视频的解决方法包括以下步骤：

步骤1：添加权限和依赖项 在AndroidManifest.xml文件中添加以下权限：

在app的build.gradle文件中添加以下依赖项：

implementation 'androidx.camera:camera-camera2:1.1.0-alpha03'
implementation 'androidx.camera:camera-lifecycle:1.1.0-alpha03'
implementation 'androidx.camera:camera-view:1.0.0-alpha24'
implementation 'androidx.camera:camera-core:1.1.0-alpha03'

步骤2：布局文件 在布局文件中添加一个预览视图和一个叠加层视图：

步骤3：创建相机实例 在Activity或Fragment中创建一个相机实例：

private lateinit var camera: Camera

private fun startCamera() {
    val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
    cameraProviderFuture.addListener(Runnable {
        val cameraProvider = cameraProviderFuture.get()
        val preview = Preview.Builder().build().also {
            it.setSurfaceProvider(previewView.createSurfaceProvider())
        }
        val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA
        camera = cameraProvider.bindToLifecycle(this, cameraSelector, preview)
        cameraControl = camera.cameraControl
    }, ContextCompat.getMainExecutor(this))
}

步骤4：创建叠加层视图 在Activity或Fragment中创建一个叠加层视图：

val overlayView: View = LayoutInflater.from(this).inflate(R.layout.overlay_layout, overlayView, false)
overlayView.visibility = View.VISIBLE
overlayView.alpha = 0.5f
overlayView.setBackgroundColor(Color.RED)
overlayView.setOnClickListener {
    // 处理叠加层点击事件
}
overlayView.setOnTouchListener { _, event ->
    // 处理叠加层触摸事件
    true
}
overlayView.layoutParams = FrameLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.MATCH_PARENT)
overlayView.isClickable = true
overlayView.isFocusable = true
overlayView.requestFocus()
overlayView.setOnKeyListener { _, keyCode, event ->
    // 处理叠加层按键事件
    false
}
overlayView.setOnLongClickListener {
    // 处理叠加层长按事件
    true
}
overlayLayout.addView(overlayView)

步骤5：在预览中绘制叠加层 在相机预览中绘制叠加层：

val surfaceTexture = SurfaceTexture(0)
overlayView.surfaceTexture = surfaceTexture
val surface = Surface(surfaceTexture)
val imageReader = ImageReader.newInstance(previewView.width, previewView.height, ImageFormat.RGB_565, 2)
imageReader.setOnImageAvailableListener({ reader ->
    val image = reader.acquireLatestImage()
    // 在叠加层上绘制图像
    val canvas = overlayView.lockCanvas()
    canvas.drawBitmap(image.toBitmap(), 0f, 0f, null)
    overlayView.unlockCanvasAndPost(canvas)
    image.close()
}, null)
cameraSession = camera.cameraControl.startFocusAndMetering(FocusMeteringAction.Builder().setAutoCancelDuration(5, TimeUnit.SECONDS).build())
cameraSession.capture(imageReader.surface, object : CameraCaptureSession.CaptureCallback() {}, null)

通过以上步骤，您可以将叠加层添加到相机实时视频中。请根据您的需求自定义叠加层的样式和逻辑。