[iOS][PlatformView] Conflict between Flutter ListView scrolling and PlatformView

[delfme]

Steps to reproduce

This example highlights a conflict between Flutter's scrolling and the native platform view's TextView scrolling and text selection. Specifically, text selection in the TextView only works when ListView scrolling is disabled using physics: NeverScrollableScrollPhysics(). This limitation affects the usability of TextView and could also impact other types of platform views.
Note: This issue occurs only on iOS.

Expected results

Users should be able to select text even when the TextView is inside a scrollable widget.

Actual results

User cannot select text when TextView is inside a scrollable Widget and scrolling is enabled.

Code sample

flutter_native_text_view_sample_main.zip

Code sample

Run this ready code:
Screen has 3 Texts elements:

• the first one is flutter widget
• the other two are platform views.
  Try to select text, it works with flutter widget but doesn't work with platform views. If scrolling is disable, text selection works also with platform views. After testing we think there is a conflict at low level.
  Sample here:

Screenshots or Video

Screenshots / Video demonstration

• Flutter's SelectableText: Text selection works as expected.
• Native Platform View: Text selection is hindered by scrolling functionality.

videozip_1349.MP4

Flutter Doctor output

Doctor output

[!] Flutter (Channel [user-branch], 3.24.5, on macOS 14.2.1 23C71 darwin-arm64, locale en-IT)
    ! Flutter version 3.24.5 on channel [user-branch] at /Users/delfme/Development/flutter
      Currently on an unknown channel. Run `flutter channel` to switch to an official channel.
      If that doesn't fix the issue, reinstall Flutter by following instructions at https://flutter.dev/setup.
    ! Upstream repository unknown source is not a standard remote.
      Set environment variable "FLUTTER_GIT_URL" to unknown source to dismiss this error.
[✓] Android toolchain - develop for Android devices (Android SDK version 34.0.0)
[✓] Xcode - develop for iOS and macOS (Xcode 15.2)
[✓] Chrome - develop for the web
[✓] Android Studio (version 2024.1)
[✓] Connected device (4 available)
    ! Error: Browsing on the local area network for iPhone. Ensure the device is unlocked and attached with a cable or associated with the same local area
      network as this Mac.
      The device must be opted into Developer Mode to connect wirelessly. (code -27)
[✓] Network resources

[delfme]

Another point to note is the poor loading performance of PlatformView, especially on android (using the same sample for testing). Rendering a TextView with five lines of text may take 1-2 seconds to display widget, whereas the expected delay should be only a few ms.

In such cases, displaying a placeholder to create the illusion of responsiveness is not an option.

[huycozy]

Hi @delfme
When running your sample project on iOS, I encounter this error:

Error running pod install

It seems to be an issue with pod install, so when I trigger it, I got detailed error:

[!] Unable to find a target named `RunnerTests` in project `Runner.xcodeproj`, did find `Runner`.

Can you please recheck and update sample with a fix? Thank you!

[delfme]

My apologies, I’ll update it soon. Were you able to confirm the slow loading performance on Android? It should compile on Android as is.

[delfme]

@huycozy I can use only github web to upload to that repo and seems it doesn't allow me to upload xcodeproj extension.
I attach here the zipped repo. Let me know if it works.

flutter_native_text_view_sample_main.zip

[huycozy]

Thanks for your update with sample code. I'm able to run it on iOS now.

Were you able to confirm the slow loading performance on Android?

Please file a separate issue for better tracking( performance issue template).

It should compile on Android as is.

When running the sample on Anroid, I encounter this below error, it is about missing namespace in Android from package simple_platform_view. Looks like you need to fork, fix and re-link it to pass this error. Then can you try on Android to see if the original issue doesn't happen there? Need to know if this is a platform-specific issue on iOS only or a framework issue in general.

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring project ':simple_platform_view'.
> Could not create an instance of type com.android.build.api.variant.impl.LibraryVariantBuilderImpl.
   > Namespace not specified. Specify a namespace in the module's build file. See https://d.android.com/r/tools/upgrade-assistant/set-namespace for information about setting the namespace.

[delfme]

@huycozy I updated the zip file, that dependency was not used. Please have a look.

[darshankawar]

Thanks for the update. I was able to replicate this on iOS specifically based on the replication steps. This occurs in latest sdk versions.

stable : 3.27.3
master : 3.29.0-1.0.pre.127