AndroidCameraRenderer.cs

using System;
using OverlayCameraSample.Controls;
using OverlayCameraSample.Droid.Renderers;
using OverlayCameraSample.Droid.Views;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;
using static OverlayCameraSample.Droid.Views.BaseCameraView;
using Android.OS;

[assembly: ExportRenderer(typeof(CameraPreview), typeof(CameraPreviewRenderer))]
namespace OverlayCameraSample.Droid.Renderers
{
	public class CameraPreviewRenderer : ViewRenderer<CameraPreview, BaseCameraView>
	{
        public CameraImplementation CameraImplementation { get; }
        BaseCameraView cameraPreview;

        public CameraPreviewRenderer()
        {
            CameraImplementation = (Build.VERSION.SdkInt >= BuildVersionCodes.Lollipop) ? CameraImplementation.NewCamera2API
                                                                                       : CameraImplementation.DefaultCameraAPI;
        }

        protected override void OnElementChanged(ElementChangedEventArgs<OverlayCameraSample.Controls.CameraPreview> e)
        {
            base.OnElementChanged(e);

            if (Control == null)
            {
                var camFacing = ((Element.Camera == OverlayCameraSample.Controls.CameraOptions.Front) ? Android.Hardware.CameraFacing.Front : Android.Hardware.CameraFacing.Back);

                switch (CameraImplementation)
                {
                    case CameraImplementation.DefaultCameraAPI:
                        cameraPreview = new CameraView(Context, camFacing, Element?.ShowCircleOverlayMask ?? false, Element.CameraMode);
                        break;
                    case CameraImplementation.NewCamera2API:
                        cameraPreview = new Camera2View(Context, camFacing, Element?.ShowCircleOverlayMask ?? false, Element.CameraMode);
                        break;
                }

                SetNativeControl(cameraPreview);
            }

            if (e.OldElement != null)
            {
                // Unsubscribe
                cameraPreview.ImageCaptured -= OnImageCaptured;
            }

            if (e.NewElement != null)
            {
                try
                {
                    cameraPreview.FaceOverlayColor = Element.CircleOverlayColor.ToAndroid();
                    cameraPreview.FaceOverlayOpacity = Element.CircleOverlayOpacity;
                    cameraPreview.StopOnCapture = Element.CameraStopOnImageCapture;

                    Element.TakePictureCommand = new Command(() => Control.CaptureImage());
                    Element.PrepareCameraCommand = new Command(() => cameraPreview.StartCamera());
                    Element.StopCameraCommand = new Command(() => cameraPreview.StopCamera());
                }
                catch (Exception ex)
                {
                    System.Diagnostics.Debug.WriteLine(ex.Message);
                }

                // Subscribe
                cameraPreview.ImageCaptured += OnImageCaptured;
            }
        }

        protected override void OnElementPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
        {
            base.OnElementPropertyChanged(sender, e);

            if (OverlayCameraSample.Controls.CameraPreview.FlashProperty.PropertyName == e.PropertyName)
            {
                cameraPreview.SwitchFlash(Element.Flash);
            }
            else if (OverlayCameraSample.Controls.CameraPreview.CameraProperty.PropertyName == e.PropertyName)
            {
                Element.Flash = false;
                cameraPreview.FlipCamera();
            }
            else if (OverlayCameraSample.Controls.CameraPreview.ShowCircleOverlayMaskProperty.PropertyName == e.PropertyName)
            {
                cameraPreview.ShowOverlay = Element.ShowCircleOverlayMask;
            }
            else if (OverlayCameraSample.Controls.CameraPreview.CircleOverlayColorProperty.PropertyName == e.PropertyName)
            {
                cameraPreview.FaceOverlayColor = Element.CircleOverlayColor.ToAndroid();
            }
            else if (OverlayCameraSample.Controls.CameraPreview.CircleOverlayOpacityProperty.PropertyName == e.PropertyName)
            {
                cameraPreview.FaceOverlayOpacity = Element.CircleOverlayOpacity;
            }
            else if (OverlayCameraSample.Controls.CameraPreview.CameraStopOnImageCaptureProperty.PropertyName == e.PropertyName)
            {
                cameraPreview.StopOnCapture = Element.CameraStopOnImageCapture;
            }
        }

        void OnImageCaptured(object sender, Tuple<string, bool, long> imageParams)
        {
            Element?.OnPictureTaken(this, imageParams);
        }


        protected override void OnLayout(bool changed, int l, int t, int r, int b)
        {
            base.OnLayout(changed, l, t, r, b);

            if (CameraImplementation == CameraImplementation.NewCamera2API)
            {
                var camera2Preview = cameraPreview as Camera2View;
                camera2Preview?.OnLayout(l, t, r, b);
            }
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                this.Control?.CloseCamera();
            }

            base.Dispose(disposing);
        }
    }

   
}