在 Xamarin 表单中实现自定义 Webview

Question

我是 Xamarin.Forms 的新手，我已经在 Droid 项目中实现了一个自定义 Web 视图渲染器。

问题是在iOS 项目中实现渲染器时，就像Webview 在没有加载CSS 和Javascript 的情况下进行了初始化。因为它只显示HTML 页面，没有任何功能。

经过一番研究，我知道我们必须实现WKWebviewRenderer，并且我们必须在iOS 中加载LoadFileUrl 方法，但我仍然无法在渲染器中捕获url。

任何人都知道如何将以下Android Renderer代码实现到iOS Renderer中？？

Droid 项目中的自定义渲染器：

[assembly: ExportRenderer(typeof(Xamarin.Forms.WebView), typeof(MyProject.Droid.WebViewRenderer))]
namespace MyProject.Droid
{
    public class WebViewRenderer : Xamarin.Forms.Platform.Android.WebViewRenderer
    {
        private bool isMyCustomWebview = false;
        public IWebViewController ElementController => Element;

        protected override void OnElementChanged(Xamarin.Forms.Platform.Android.ElementChangedEventArgs<Xamarin.Forms.WebView> e)
        {
            base.OnElementChanged(e);
            if (e.NewElement.GetType() == typeof(MyCustomWebview))
            {
                Control.SetWebViewClient(new Callback(this));
                isMyCustomWebview = true;
            }
            else
            {
                Control.SetWebViewClient(new Callback(Plugin.CurrentActivity.CrossCurrentActivity.Current.Activity));
                isMyCustomWebview = false;
            }
        }


        public class Callback : WebViewClient
        {
            Activity _context;
            public Callback(Activity _context)
            {
                this._context = _context;
            }

            WebViewRenderer _renderer;

            public Callback(WebViewRenderer renderer)
            {
                _renderer = renderer ?? throw new ArgumentNullException("Renderer");
            }

            public override void OnPageStarted(Android.Webkit.WebView view, string url, Android.Graphics.Bitmap favicon)
            {
                base.OnPageStarted(view, url, favicon);
                if (_renderer != null && _renderer.isMyCustomWebview)
                {
                    DependencyService.Get<ILoadingIndicator>().Show();
                    var args = new WebNavigatingEventArgs(WebNavigationEvent.NewPage, new UrlWebViewSource { Url = url }, url);
                    _renderer.ElementController.SendNavigating(args);
                }

            }
            public override void OnPageFinished(Android.Webkit.WebView view, string url)
            {
                base.OnPageFinished(view, url);
                if (_renderer != null && _renderer.isMyCustomWebview)
                {
                    DependencyService.Get<ILoadingIndicator>().Dismiss();
                    var source = new UrlWebViewSource { Url = url };
                    var args = new WebNavigatedEventArgs(WebNavigationEvent.NewPage, source, url, WebNavigationResult.Success);
                    _renderer.ElementController.SendNavigated(args);
                }
            }
        }
    }
}

更新：iOS 项目中的自定义渲染器：

[assembly: ExportRenderer(typeof(Xamarin.Forms.WebView), typeof(MyProject.iOS.WebViewRenderer))]
namespace MyProject.iOS
{
    // Xamarin.Forms.Platform.iOS.WebViewRenderer
    public class WebViewRenderer : ViewRenderer<WebView, WKWebView>
    {
        WKWebView wkWebView;

        protected override void OnElementChanged(ElementChangedEventArgs<WebView> e)
        {
            base.OnElementChanged(e);
            if (Control != null) return;
            var config = new WKWebViewConfiguration();
            wkWebView = new WKWebView(Frame, config) { NavigationDelegate = new MyNavigationDelegate() };
            SetNativeControl(wkWebView);
        }
    }

    public class MyNavigationDelegate : WKNavigationDelegate
    {
        public override void DidFinishNavigation(WKWebView webView, WKNavigation navigation)
        {

            //get url here
            var url = webView.Url;

            // webView.LoadFileUrl(url, url);

        }
    }
}

更新：

这是我在可移植项目中为 webview 设置源 URL 和基本 URL 的方式：

var result = await client.PostAsync("/embedded/pay", content);
if (result.IsSuccessStatusCode)
{
    var resp = await result.Content.ReadAsStringAsync();
    var html = new HtmlWebViewSource
    {
        Html = resp,
        BaseUrl = paymentGatewayUrl
    };

    //Adding Cookie
    CookieContainer cookies = new CookieContainer();
    var domain = new Uri(html.BaseUrl).Host;
    var cookie = new Cookie
    {
        Secure = true,
        Expired = false,
        HttpOnly = false,
        Name = "cookie",
        Expires = DateTime.Now.AddDays(10),
        Domain = domain,
        Path = "/"
    };
    cookies.Add(new Uri(html.BaseUrl), cookie);
    webView.Source = html;
}

Answer 1

您可以修改自定义渲染器的代码，如下所示。

[assembly: ExportRenderer(typeof(WebView), typeof(MyWebViewRenderer))]
namespace xxx.iOS
{

    public class MyWebViewRenderer : ViewRenderer<WebView, WKWebView>
    {
        WKWebView wkWebView;

        protected override void OnElementChanged(ElementChangedEventArgs<WebView> e)
        {
            base.OnElementChanged(e);

            if (Control != null) return;
            var config = new WKWebViewConfiguration();
            wkWebView = new WKWebView(Frame, config) { NavigationDelegate = new MyNavigationDelegate() };
            SetNativeControl(wkWebView);
        }
    }

    public class MyNavigationDelegate : WKNavigationDelegate
    {
        public override void DidFinishNavigation(WKWebView webView, WKNavigation navigation)
        {

            //get url here
            var url = webView.Url;

            //webView.LoadFileUrl();

        }
    }
}

Answer 2

iOS 渲染器：

using WebKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;

[assembly: ExportRenderer(typeof(WebView), typeof(MyNamespace.iOS.MyWebViewRenderer))]
namespace MyNamespace.iOS
{
  //WkWebViewRenderer inherits from WKWebView
  public class MyWebViewRenderer : WkWebViewRenderer
  {
    protected override void OnElementChanged(VisualElementChangedEventArgs e)
    {
        base.OnElementChanged(e);

        if (e.NewElement != null)
        {
            WKWebView wkWebView = this;
            wkWebView.NavigationDelegate = new MyNavigationDelegate(); //not shown here
        }
    }
  }
}