492b6f7ddf
The documentation for using `findChildIndexCallback` recommends using `indexOf`, but that causes [this line](05259ca938/packages/flutter/lib/src/rendering/sliver_multi_box_adaptor.dart (L259)) to throw in debug mode, and when using `SliverList`, it breaks the render.
This PR changes the usage to check if the index is not negative before using it, and changes to return `null` instead if the child wasn't able to be found.
There's the related issue #107123, but this doesn't actually fix it.
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This PR has been updated to add the snippets that were used in the `findChildIndexCallback` comment as examples with proper tests, as well as updating the comment to reference the new examples.
Flutter Examples
This directory contains several examples of using Flutter. To run an example,
use flutter run inside that example's directory. See the getting started
guide to install the flutter tool.
For additional samples, see the
flutter/samples repo.
Available examples include:
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Hello, world The hello world app is a minimal Flutter app that shows the text "Hello, world!"
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Flutter gallery The flutter gallery app no longer lives in this repo. Please see the gallery repo.
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Layers The layers vignettes show how to use the various layers in the Flutter framework. For details, see the layers README.
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Platform Channel The platform channel app demonstrates how to connect a Flutter app to platform-specific APIs. For documentation, see https://flutter.dev/platform-channels/.
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Platform Channel Swift The platform channel swift app is the same as platform channel but the iOS version is in Swift and there is no Android version.
Notes
Note on Gradle wrapper files in .gitignore:
Gradle wrapper files should normally be checked into source control. The example projects don't do that to avoid having several copies of the wrapper binary in the Flutter repo. Instead, the Gradle wrapper is injected by Flutter tooling, and the wrapper files are .gitignore'd to avoid making the Flutter repository dirty as a side effect of running the examples.