Blocking WebView Links (Android)

Question

Blocking WebView Links (Android)

валера карманов 396

Is there any event that will occur when clicking on a link in the "WebView" element?

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,156 Reputation points Microsoft External Staff

2024-10-17T01:47:23.8266667+00:00

May I know whether your issue has been solved or not? If you're still having problems, please explain in detail what is still going wrong and what you need help with.

1 answer

Your answer

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,156 Reputation points Microsoft External Staff

2024-10-17T01:47:23.8266667+00:00

May I know whether your issue has been solved or not? If you're still having problems, please explain in detail what is still going wrong and what you need help with.

Answer 1

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,156 Microsoft External Staff

Hello,

Maui Webview provides two navigation events to handle events during and after a page navigating.

You could refer to the official documentation and sample code below.

WebView

WebView defines a Navigating event that's raised when page navigation starts, and a Navigated event that's raised when page navigation completes. The WebNavigatingEventArgs object that accompanies the Navigating event defines a Cancel property of type bool that can be used to cancel navigation. The WebNavigatedEventArgs object that accompanies the Navigated event defines a Result property of type WebNavigationResult that indicates the navigation result.

// in xaml
<WebView  Source="
https://cn.bing.com/"
WidthRequest="200" HeightRequest="300" 
             Navigating="WebView_Navigating" Navigated="WebView_Navigated"/>

// in code-behind
private void WebView_Navigating(object sender, WebNavigatingEventArgs e)
{
    Console.WriteLine(e.Url);
}
 
private void WebView_Navigated(object sender, WebNavigatedEventArgs e)
{
    Console.WriteLine(e.Url);
}

Best Regards,

Alec Liu.

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валера карманов 396 Reputation points

2024-10-14T05:40:25.86+00:00

I added these events, but for some reason they are not executed. The transition to links does not work
валера карманов 396 Reputation points

2024-10-14T05:41:04.56+00:00

[eglCodecCommon] glUtilsParamSize: unknow param 0x000088ef

[eglCodecCommon] glUtilsParamSize: unknow param 0x000088ef

[EGL_emulation] eglMakeCurrent: 0x7adb799f40a0: ver 3 0 (tinfo 0x7adb79b9dce0)
валера карманов 396 Reputation points

2024-10-14T05:41:15.2133333+00:00

123456
Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,156 Reputation points Microsoft External Staff

2024-10-14T05:51:03.6366667+00:00
I added these events, but for some reason they are not executed. The transition to links does not work

For further investigation, could you please provide the following information?

Could you please provide the API level of the Android emulator?

Could you please provide specific steps to reproduce or examples of minimized recurrence? And provide your expected behavior, the actual behavior of the program at the moment, and what are the differences between them?

валера карманов 396

public QuestionPage()
{
	SetBinding(TitleProperty, new Binding { Path = "title" });
	var htmlSource = new HtmlWebViewSource();
	htmlSource.SetBinding(
		HtmlWebViewSource.HtmlProperty,
		new Binding { Path = "introtext" }
	);
	var webView = new WebView { Source = htmlSource };
	webView.Navigating += OnWebViewNavigating;
	webView.Navigated += OnWebViewNavigated;
	Content = webView;
}
private void OnWebViewNavigating(object sender, WebNavigatingEventArgs e)
{
	Debug.WriteLine("OnWebViewNavigating : " + e.Url);
}
private void OnWebViewNavigated(object sender, WebNavigatedEventArgs e)
{
	Debug.WriteLine("OnWebViewNavigated : " + e.Url);
}

The fact that clicking on links doesn't work is correct, but the events you specified aren't executed.

Android 10.0 - API 29

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,156 Microsoft External Staff

I set up a Link for the WebView using the same approach as you. the navigation event fires as expected on click.

public MainPage()
{
    InitializeComponent();
    WebView webView = new WebView
    {
        Source = new HtmlWebViewSource
        {
            Html = @"<HTML><BODY><H1>.NET MAUI</H1><P>Welcome to WebView.</P><a href=""
https://learn.microsoft.com/en-us/dotnet/maui/user-interface/controls/webview?view=net-maui-8.0&pivots=devices-android"">Maui
WebView</a> </BODY></HTML>"
        }
    };
    webView.Navigating += OnWebViewNavigating;
    webView.Navigated += OnWebViewNavigated;
    Content = webView;
}
private void OnWebViewNavigating(object sender, WebNavigatingEventArgs e)
{
    Debug.WriteLine("OnWebViewNavigating : " + e.Url);
}
private void OnWebViewNavigated(object sender, WebNavigatedEventArgs e)
{
    Debug.WriteLine("OnWebViewNavigated : " + e.Url);
}

When I click on the Maui Webview link, the following output appears on the console.

[0:] OnWebViewNavigating :
https://learn.microsoft.com/en-us/dotnet/maui/user-interface/controls/webview?view=net-maui-8.0&pivots=devices-android
[0:] OnWebViewNavigated :
https://learn.microsoft.com/en-us/dotnet/maui/user-interface/controls/webview?view=net-maui-8.0&pivots=devices-android

For further investigation, could you please provide details on how you are doing the binding and setting up the Html text?

валера карманов 396

There may be a problem with data binding.

var result = new HelpQuestion {
	title = "Demo Question",
	introtext = @"<HTML><BODY><H1>.NET MAUI</H1><P>Welcome to WebView.</P><a href=""
https://learn.microsoft.com/en-us/dotnet/maui/user-interface/controls/webview?view=net-maui-8.0&pivots=devices-android"">Maui
WebView</a> </BODY></HTML>"
};

SetBinding(TitleProperty, new Binding { Path = "title", Source = result });
var htmlSource = new HtmlWebViewSource();

htmlSource.SetBinding(
	HtmlWebViewSource.HtmlProperty, new Binding { Path = "introtext" }
);

var webView = new WebView { Source = htmlSource };

webView.Navigating += OnWebViewNavigating;
webView.Navigated += OnWebViewNavigated;

Content = webView;

public class HelpQuestion : IObject
{
    public string id { get; set; } = "";
    public string title { get; set; } = "";
    public string introtext { get; set; } = "";
}

enter image description here

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,156 Microsoft External Staff

This is caused by the wrong use of data binding. If you need to use HtmlSource via data binding, please refer to the following steps and official documentation.

Step 1. Create a corresponding ViewModel for the page.

internal class QuestionViewmodel : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler? PropertyChanged;
        public void OnPropertyChanged([CallerMemberName] string name = "") =>
       PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
 
        public HelpQuestion HelpQuestion
        {
            get
            {
                return helpQuestion;
            }
            set
            {
                if (helpQuestion != value)
                {
                    helpQuestion = value;
                    OnPropertyChanged();
                }
            }
        }
 
        private HelpQuestion helpQuestion;
 
        public QuestionViewmodel()
        {
            HelpQuestion = new HelpQuestion
            {
                title = "Demo Question",
                introtext = @"<HTML><BODY><H1>.NET MAUI</H1><P>Welcome to WebView.</P><a href=""
https://learn.microsoft.com/en-us/dotnet/maui/user-interface/controls/webview?view=net-maui-8.0&pivots=devices-android"">Maui
WebView</a> </BODY></HTML>"
            };
        }
    }

Step 2. Set bindings for pages and page elements.

public MainPage()
{
    InitializeComponent();
    var vm = new QuestionViewmodel();
    this.BindingContext = vm;
    SetBinding(TitleProperty, new Binding { Path = "HelpQuestion.title" });
    var htmlSource = new HtmlWebViewSource();
 
    htmlSource.SetBinding(
        HtmlWebViewSource.HtmlProperty, new Binding { Path = "HelpQuestion.introtext" }
    );
    var webView = new WebView { Source = htmlSource };
 
    webView.Navigating += OnWebViewNavigating;
    webView.Navigated += OnWebViewNavigated;
    Content = webView;
}

Data binding and MVVM.

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,156 Reputation points Microsoft External Staff

2024-10-28T05:33:29.9566667+00:00

May I know whether your issue has been solved or not? If you're still having problems, please explain in detail what is still going wrong and what you need help with.

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Blocking WebView Links (Android)

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