Cannot scroll webpage in WebView element on Xamarin Shell

[Soul-Master]

Description

Steps to Reproduce

1. Pull Gastropods project from Github
   https://github.com/davidortinau/Gastropods.git
2. Update Xamarin Form to latest prerelease version ()
3. Replace content of MainPage.xaml page with single WebView element

<WebView Source="https://www.youtube.com/" ></WebView>

4. Build & Debug
5. After loaded, try to scroll YouTube page

Expected Behavior

YouTube webpage should be scrolled.

Actual Behavior

Nothing happened after scrolling.

Basic Information

• Version with issue: 4.0.0.135214-pre4, 4.0.0.8055-pre1
• Last known good version: -
• IDE: VS 2017 15.9.6
• Platform Target Frameworks:
  • Android: Android Pie (9.0)
• Nuget Packages:
• Affected Devices: Samsung S7 Edge (Android 8.0)
  Parent: Xamarin.Forms.Shell Spec #2415

[pauldipietro]

Reproducible by modifying a Shell template in VS2019 preview.

[jannikscho]

Hello,

The problem also occurs in my project with WebView and Maps (Xamarin.Forms.GoogleMaps).
I could solve it easily by a custom ContentView.

See below...

Shared-Project:

Create a custom ContentView:
public class GesturelessContentView : ContentView { }

In Xaml add the WebView to this ContentView:

<controls:GesturelessContentView x:Name="view" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand"> <WebView x:Name="webView" Source="{Binding Source}" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand"/> </controls:GesturelessContentView>

Android-Project:
Create a custom ViewRenderer for this ContentView and override the "DispatchTouchEvent":

public override bool DispatchTouchEvent(MotionEvent e) { /* Switching between touch-events switch (e.Action) { case MotionEventActions.Down: case MotionEventActions.Move: case MotionEventActions.Up: this.Parent.RequestDisallowInterceptTouchEvent(true); break; }*/ // For all touch-events this.Parent.RequestDisallowInterceptTouchEvent(true); return base.DispatchTouchEvent(e); }

In my case it works as expected.

[g4mb10r]

I have this issue as well. Please fix.

[philousb]

Hello,

Having the same issue in 4.0.0 pre 9. Will this be fixed soon ?

[jannikscho]

The problem is still there. Tested with preview 9.

[samhouts]

As a workaround, you can create a custom renderer for your WebView and add the following override:

		public override bool DispatchTouchEvent(MotionEvent e)
		{
			Parent.RequestDisallowInterceptTouchEvent(true);
			return base.DispatchTouchEvent(e);
		}

[philousb]

It works for me.
thx.

[wagenheimer]

As a workaround, you can create a custom renderer for your WebView and add the following override:

		public override bool DispatchTouchEvent(MotionEvent e)
		{
			Parent.RequestDisallowInterceptTouchEvent(true);
			return base.DispatchTouchEvent(e);
		}

Could you please explain how can I do this?

[philousb]

You have to create a custom renderer for the webview (Android, iOS)

1. create a custom webview

using System;
using System.Collections.Generic;
using System.Text;
using Xamarin.Forms;

namespace MyNamespace
{
    public class MyWebView : WebView
    {
    }
}

2. For each project create a custom renderer

using Android.Content;
using Android.Views;

using Xamarin.Forms.Platform.Android;
using Xamarin.Forms;

using MyNamespace;
using MyNamespace.Droid;

[assembly: ExportRenderer(typeof(MyWebView), typeof(MyWebViewRenderer))]
namespace MyNamespace.Droid
{
    class MyWebViewRenderer : WebViewRenderer
    {
        public MyWebViewRenderer(Context context) : base(context)
        {
        }

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

        public override bool DispatchTouchEvent(MotionEvent e)
        {
            Parent.RequestDisallowInterceptTouchEvent(true);
            return base.DispatchTouchEvent(e);
        }
    }
}

[dgerding]

This is still not working for me. I get the same "no scrolling" behavior in standard WebView and when using Xam.Plugin.Web. This seems like a pretty big bug since webviews are common. Help :) ?

[samhouts]

#6310

[MSiccDev]

I can confirm that the workaround works (at least for Android). Even though I would prefer it to work out of the box...

[samhouts]

closed by #7032

[jonhudson12]

@philousb - you sir deserve a medal. Works perfect. Ty!

[blndr83]

I have tried philousb custom webview renderer on a contentpage with a scrollview inside the scrollview a grid and in the grid at the 3 Row a webview. Without the custom renderer scrolling works only in landscape mode. With the custom renderer it works only when it is not in landscape mode. When i remove the scrollview it works with standard webview in both modes. Tested on a Huawei p20 pro with android 9

[MauriceMatekCode]

Hey there - my name is Maurice.

Weirdly this whole thing doesn't seem to work for me.
I use the pdfjs-Library to display a local pdf-file in a WebView on Android. I am using Xamarin-Forms-Shell.

I am also using an instance of WebView with a CustomRenderer linked to it as mentioned in this thread before. Inside the Custom Renderer for Android I have the following code to fix the scrolling bug:

public override bool DispatchTouchEvent(MotionEvent e) { Parent.RequestDisallowInterceptTouchEvent(true); return base.DispatchTouchEvent(e); }

the problem is: scrolling still does not work. Sometimes although, when using two fingers and scrolling fast it zooms a little and scrolls a bit.

I really don't know what I could do about that. Which is quite frustrating.

Thanks for any help
Maurice

[MauriceMatekCode]

Hey there - my name is Maurice.

Weirdly this whole thing doesn't seem to work for me.
I use the pdfjs-Library to display a local pdf-file in a WebView on Android. I am using Xamarin-Forms-Shell.

I am also using an instance of WebView with a CustomRenderer linked to it as mentioned in this thread before. Inside the Custom Renderer for Android I have the following code to fix the scrolling bug:

public override bool DispatchTouchEvent(MotionEvent e) { Parent.RequestDisallowInterceptTouchEvent(true); return base.DispatchTouchEvent(e); }

the problem is: scrolling still does not work. Sometimes although, when using two fingers and scrolling fast it zooms a little and scrolls a bit.

I really don't know what I could do about that. Which is quite frustrating.

Thanks for any help
Maurice

I was able to fix the issue by using Xamarin.Forms 5.0 and the newest prerelease of pdfjs.

Thanks anyway ^^

[scott-hooper-hordernit]

You have to create a custom renderer for the webview (Android, iOS)

1. create a custom webview

using System;
using System.Collections.Generic;
using System.Text;
using Xamarin.Forms;

namespace MyNamespace
{
    public class MyWebView : WebView
    {
    }
}

1. For each project create a custom renderer

using Android.Content;
using Android.Views;

using Xamarin.Forms.Platform.Android;
using Xamarin.Forms;

using MyNamespace;
using MyNamespace.Droid;

[assembly: ExportRenderer(typeof(MyWebView), typeof(MyWebViewRenderer))]
namespace MyNamespace.Droid
{
    class MyWebViewRenderer : WebViewRenderer
    {
        public MyWebViewRenderer(Context context) : base(context)
        {
        }

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

        public override bool DispatchTouchEvent(MotionEvent e)
        {
            Parent.RequestDisallowInterceptTouchEvent(true);
            return base.DispatchTouchEvent(e);
        }
    }
}

Did you have an iOS version of this custom renderer? I don't think iOS handles touch events like this.