Xamarin.Forms.WebView初始加载指示器 [英] Xamarin.Forms.WebView initial loading indicator

问题描述

我采用Xamarin表单WebView并为首次加载添加加载进度栏的最简单方法是什么?

What is the simplest way for me to take a Xamarin forms WebView and add a loading progress bar for the first load?

我的应用程序只是包装了一个网站，但在启动画面消失并且WebView正在加载其内容的带宽不佳的情况下，我当然会看到一个白屏.

My application simply wraps a website but in poor bandwidth scenarios when the splash screen disappears and the WebView is loading it's content I of course see a white screen.

我希望看到进度指示器.我环顾四周，但没有找到简单的解决方案，而且大多数问题都不针对Xamarin.Forms.

I would like to see a progress indicator. I have looked around but haven't found a simple solution to this and most questions are not oriented towards Xamarin.Forms.

谢谢.

亲切的问候， 标记

推荐答案

只需将StackLayout与ActivityIindicator和WebView用作子项，并根据在 WebView.Navigating 和 WebView.Navigated 事件中设置的IsWorking属性值设置其可见性.您的ViewModel必须实现IOnPropertyChanged.

Just use StackLayout with ActivityIindicator and WebView as children and set it's visibility based on IsWorking property value which is set in WebView.Navigating and WebView.Navigated events. Your ViewModel has to implement IOnPropertyChanged.

var webViewView = new WebView() {
    HorizontalOptions = LayoutOptions.FillAndExpand,
    VerticalOptions = LayoutOptions.FillAndExpand,
};
webViewView.SetBinding<YourViewModel>(View.IsVisibleProperty, v => v.IsWorking, 
    BindingMode.OneWay, new Converters.NegateBoolConverter());

webViewView.Navigating += (sender, e) => {
    viewModel.IsWorking = true;
};

webViewView.Navigated += (sender, e) => {
    viewModel.IsWorking = false;
};

var activityIndicator = new ActivityIndicator() {
    HorizontalOptions = LayoutOptions.Center,
    VerticalOptions = LayoutOptions.Center,
};
activityIndicator.SetBinding<YourViewModel>(ActivityIndicator.IsRunningProperty, v => v.IsWorking);

var isWorkingView = new ContentView() {
    HorizontalOptions = LayoutOptions.FillAndExpand,
    VerticalOptions = LayoutOptions.FillAndExpand,
    Content = activityIndicator
};
isWorkingView.SetBinding<YourViewModel>(ContentView.IsVisibleProperty, v => v.IsWorking);

var root = new StackLayout() {
    HorizontalOptions = LayoutOptions.FillAndExpand,
    VerticalOptions = LayoutOptions.FillAndExpand,
    Children = {
        webViewView,
        isWorkingView,
    }
};

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