Example: filterExpansionData bug

[johnareid54]

Running the example code without any alternation causes it to hang when the search box is entered. The code gets to line 232 filterExpansionData.

Got this error:

════════ Exception caught by foundation library ════════════════════════════════
'package:flutter/src/material/expansion_tile.dart': Failed assertion: line 77 pos 12: '_state != null': is not true.
════════════════════════════════════════════════════════════════════════════════

Sorry I can't give you much detail, normally vscode would show the issue in the debug console, but it just seems to hang. I am running on a m1 mac, macos.

[✓] Flutter (Channel stable, 3.24.0, on macOS 14.6.1 23G93 darwin-arm64, locale en-GB)
[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.1)
[✓] Xcode - develop for iOS and macOS (Xcode 15.2)
[✓] Chrome - develop for the web
[✓] Android Studio (version 2022.3)
[✓] VS Code (version 1.92.2)

[koukibadr]

@johnareid54 thanks for your feedback, indeed I've found the bug once fixed I'll let you know

[johnareid54]

I believe the issue that the error is being caused because the listView does not know the data items until the header is expanded.
One solution might be to filter the data before submitting it to the listView and show records with fake data headers - after all if a search is being called the user would want to see all matching records.

[koukibadr]

@johnareid54 the issue has been fixed in the latest version check it out
the error is due to the expansion controller list when the data is filtered some of the controllers not visible so using .expand() on them will throw an exception