UIScrollView able to pan past content inside scrollview when zooming (iOS)

Cast324 commented 2 weeks ago

Description

When you enable zooming in a iOS UIScrollView you are able to pan past the content bounds. This was not the case in Xamarin.

https://github.com/dotnet/maui/assets/6510334/d089bb81-bdc3-42db-8a02-846094a87d0a

I also have a test in Xamarin for you to compare. You can see that in xamarin the content inside the scrollview is scaled up to the scrollview size despite having a width and height request this is not the case in MAUI.

https://github.com/Cast324/ScrollViewTestXamarin

Steps to Reproduce

Create a ScrollViewHandler for iOS like the following:

#if IOS
        Microsoft.Maui.Handlers.ScrollViewHandler.Mapper.AppendToMapping(nameof(CustomScrollView), (handler, view) =>
        {
            handler.PlatformView.MinimumZoomScale = 1;
            handler.PlatformView.MaximumZoomScale = 5;
            handler.PlatformView.ViewForZoomingInScrollView += (UIKit.UIScrollView sv) =>
            {
                return handler.PlatformView.Subviews[0];
            };
        });
#endif

Then add it to the view like the following:

<ContentPage x:Class="ScrollViewTestXamarin.MainPage"
             xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:items="clr-namespace:ScrollViewTestXamarin">

    <items:CustomScrollView HorizontalScrollBarVisibility="Always" VerticalScrollBarVisibility="Always">
        <ContentView BackgroundColor="Red"
                     HeightRequest="200"
                     WidthRequest="200" />
    </items:CustomScrollView>

</ContentPage>

Link to public reproduction project repository

https://github.com/Cast324/ScrollViewTestRepo

Version with bug

8.0.60 SR6

Is this a regression from previous behavior?

Yes, this used to work in Xamarin.Forms

Last version that worked well

Unknown/Other

Affected platforms

iOS

Affected platform versions

iOS 17

Did you find any workaround?

No workaround known currently.

Relevant log output

No response

github-actions[bot] commented 2 weeks ago

Hi I'm an AI powered bot that finds similar issues based off the issue title.

Please view the issues below to see if they solve your problem, and if the issue describes your problem please consider closing this one and thumbs upping the other issue to help us prioritize it. Thank you!

Open similar issues:

[iOS] UIScrollView Custom Handler's Zoom View changes position after button click or resuming from OnSleep state (#20632), similarity score: 0.78
Pan not detected vertically when the recognizer is inside of a scrollview (#17319), similarity score: 0.77

Closed similar issues:

[regression/8.0.3] Scrollview scrolling does not work in MAC and iOS platforms (#19005), similarity score: 0.78
ScrollView.ScrollToAsync on iOS scrolls also vertically when Orientation is horizontal but content view is smaller vertically than ScrollView (#21537), similarity score: 0.78
[iOS] MAUI ScrollView is not scrollable when Keyboard hides content (#15159), similarity score: 0.77

Note: You can give me feedback by thumbs upping or thumbs downing this comment.

kevinxufei commented 2 weeks ago

Verified this issue with Visual Studio 17.11.0 Preview 2.1 (8.0.60 & 8.0.40). Can repro on iOS platform with sample project. And it works fine on Xamarin.Forms

ardentra commented 1 week ago

+1 we are stuck here

reid-kirkpatrick commented 1 week ago

this is a big blocker for our conversion

dotnet / maui