iot/labs/Demo/Demo/MainPage.xaml.cs

using CameraPreview;
using Plugin.LocalNotifications;
using Plugin.Permissions;
using Plugin.Permissions.Abstractions;
using System;
using System.IO.Ports;
using System.Threading.Tasks;
using Xamarin.Forms;

namespace Demo
{
    public partial class MainPage : ContentPage
    {
        private SerialDevice _sp;

        public MainPage()
        {
            InitializeComponent();
            NavigationPage.SetHasNavigationBar(this, false);
            this.webView.Navigating += WebView_Navigating;
            this.webView.Navigated += WebView_Navigated;
            this.webView.Source = "http://localhost:5000/index.html";
        }

        protected override void OnAppearing()
        {
            base.OnAppearing();
            this.OpenSerialPort();
        }

        protected override void OnDisappearing()
        {
            base.OnDisappearing();
            this.CloseSerialPort();
        }

        private void OpenSerialPort()
        {
            if (Device.RuntimePlatform == Device.Android)
            {
                try
                {
                    this._sp = new SerialDevice("/dev/ttyS4", BaudRate.B9600, Parity.None, 8, StopBits.One, Handshake.None);
                    this._sp.DataReceived += (s, e) =>
                    {
                        try
                        {
                            if (e.Length > 0)
                            {
                                var message = BitConverter.ToString(e);
                                this.Alert(BitConverter.ToString(e));
                            }
                        }
                        catch (Exception ex)
                        {
                            this.Alert(ex.Message);
                        }
                    };
                    this._sp.Open();
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }
            }
        }

        private void CloseSerialPort()
        {
            if (Device.RuntimePlatform == Device.Android)
            {
                try
                {
                    if (this._sp != null)
                    {
                        this._sp.Close();
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }
            }
        }

        private void WebView_Navigating(object sender, WebNavigatingEventArgs e)
        {
            Console.WriteLine(e.Url);
            if (e.Url.Contains("notify.html"))
            {
                e.Cancel = true;
                CrossLocalNotifications.Current.Show("title", e.Url);
            }
            else if (e.Url.Contains("qr.html"))
            {
                e.Cancel = true;
                OpenQrScanPage();
            }
            else if (e.Url.Contains("face.html"))
            {
                e.Cancel = true;
                FaceAsync();
            }
            else if (e.Url.Contains("rtmp://") || e.Url.Contains(".flv") || e.Url.Contains(".m3u8"))
            {
                e.Cancel = true;
                this.Navigation.PushAsync(new OnvifPage(e.Url));
            }
        }

        private void WebView_Navigated(object sender, WebNavigatedEventArgs e)
        {
            Console.WriteLine(e.Result + ":" + e.Url);
            if (e.Url.EndsWith("/index.html"))
            {
                (sender as WebView)?.EvaluateJavaScriptAsync("isApp=true;");
            }
        }

        //private void Scan()
        //{
        //    var scanPage = new ZXingScannerPage();
        //    scanPage.OnScanResult += (result) =>
        //    {
        //        scanPage.IsScanning = false;
        //        Device.BeginInvokeOnMainThread(async () =>
        //        {
        //            await Navigation.PopAsync();
        //        });
        //    };
        //    this.Navigation.PushAsync(scanPage);
        //}
        private async Task OpenQrScanPage()
        {
            if (await CheckCameraPermisstions())
            {
                var scanPage = new QrScanPage();
                await this.Navigation.PushAsync(scanPage);
            }
        }

        private async Task FaceAsync()
        {
            if (await CheckCameraPermisstions())
            {
                var facePage = new FacePage(new ScanningOptionsBase { UseFrontCameraIfAvailable = true }, new ZXingOverlay());
                await Navigation.PushAsync(facePage);
            }
        }

        public void Alert(object message, string title = "<22><>ʾ", string button = "ȷ<><C8B7>")
        {
            Device.BeginInvokeOnMainThread(() =>
            {
                this.DisplayAlert(title, message.ToString(), button);
            });
        }

        private async Task<bool> CheckCameraPermisstions()
        {
            var mediaPlugin = Plugin.Media.CrossMedia.Current;
            await mediaPlugin.Initialize();

            if (!mediaPlugin.IsCameraAvailable || !mediaPlugin.IsTakePhotoSupported)
            {
                await DisplayAlert("No Camera", ":( No camera available.", "OK");
                return false;
            }

            var cameraStatus = await CrossPermissions.Current.CheckPermissionStatusAsync(Permission.Camera);

            if (cameraStatus != PermissionStatus.Granted)
            {
                var results = await CrossPermissions.Current.RequestPermissionsAsync(new[] { Permission.Camera });
                cameraStatus = results[Permission.Camera];
            }

            if (cameraStatus != PermissionStatus.Granted)
            {
                await DisplayAlert("Permissions Denied", "Unable to take photos.", "OK");
                return false;
            }
            return true;
        }
    }
}