Xamarin Forms WebView Navigated 事件未在 iOS 上一致触发

我有一个 Xamarin Forms ContentPage，它有一个 WebView 和一个 ActivityIndi​​cator。我已将事件处理程序连接到 WebView Navigating 和 Navigated 事件以激活和取消激活 ActivityIndi​​cator。这一切都适用于 Android。在 iOS 上，Navigating 事件会在页面加载时触发多次，但 Navigated 事件不会随之触发。这通常会使 ActivityIndi​​cator 处于永久激活状态。有没有人找到不涉及自定义 WebView 渲染的修复或解决方法，或者自定义渲染器是唯一可行的方法？如果需要自定义渲染器，是否有人有适用于此目的的示例？

更新：根据要求在此处添加代码。

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:vm="clr-namespace:FFXPubXam.ViewModels" 
             x:Class="FFXPubXam.Views.WebPage"
             x:Name="root"
             Shell.NavBarIsVisible="false">
    <ContentPage.Content>
        <Grid>
            <WebView x:Name="WebViewControl" 
             Source="{Binding Url}" 
             Navigating="WebViewControl_Navigating" 
             Navigated="WebViewControl_Navigated" />
            <ActivityIndicator x:Name="activity"
                               IsRunning="False"  
                               IsEnabled="False"  
                               IsVisible="False"  
                               HeightRequest="40"
                               WidthRequest="100"
                               VerticalOptions="CenterAndExpand"
                               HorizontalOptions="CenterAndExpand"
                               Color="{DynamicResource FFX_Blue4}"
                               BackgroundColor="Transparent"/>
        </Grid>
    </ContentPage.Content>
</ContentPage>

using FFXPubXam.Helpers;
using FFXPubXam.ViewModels;
using System;
using Xamarin.Forms;

namespace FFXPubXam.Views
{
    public partial class WebPage : ContentPage
    {
        public WebPage(string arg)
        {
            InitializeComponent();
            BindingContext = new WebPageViewModel(arg);
        }

        protected override void OnAppearing()
        {
            ToggleActivityIndicator(true);

            base.OnAppearing();
        }

        private void WebViewControl_Navigating(object sender, WebNavigatingEventArgs e)
        {
            ToggleActivityIndicator(true);
        }

        private void WebViewControl_Navigated(object sender, WebNavigatedEventArgs e)
        {
            ToggleActivityIndicator(false);
        }

        private void ToggleActivityIndicator(bool state)
        {
            activity.IsRunning = state;
            activity.IsEnabled = state;
            activity.IsVisible = state;
        }
    }
}