# Deprecated ExpansionTileController

> `ExpansionTileController` is deprecated and replaced by `ExpansibleController`.




:::important
These breaking change docs are accurate, as of the release
under which they are published. Over time, the
workarounds described here might become inaccurate.
We don't, in general, keep these breaking change docs up
to date as of each release.

这些破坏性改动文档的准确性仅限于其发布时对应的版本。
随着时间的推移，文档中描述的方案可能会逐渐失效。
通常情况下，我们不会在每次发布新版本时都对这些文档进行同步更新。

The [breaking change index file](/release/breaking-changes)
lists the docs created for each release.

[破坏性改动列表](/release/breaking-changes) 
列出了每个版本的文档。

:::


## Summary

`ExpansionTileController` is deprecated. The same functionality can be
achieved by using `ExpansibleController` instead.

## Background

`ExpansionTileController` programmatically expands and collapses an `ExpansionTile`. A new `Expansible` widget has been added to the widgets library, which contains logic for expanding and collapsing behavior without being tied to the Material library. `ExpansibleController` complements `Expansible` and has the same functionality as `ExpansionTileController`. Additionally, `ExpansibleController` also supports adding and notifying listeners when its expansion state changes.

Apps that use `ExpansionTileController` display the following error when run
in debug mode: "Use `ExpansibleController` instead.". Specifically, this means that users should replace usage of `ExpansionTileController` with `ExpansibleController`.

## Migration guide

To migrate, replace the `controller` parameter of an `ExpansionTile` from an `ExpansionTileController` to an `ExpansibleController`. Unlike `ExpansionTileController`, `ExpansibleController` is a `ChangeNotifier`, so remember to dispose the new `ExpansibleController`.

Code before migration:

```dart
class _MyWidgetState extends State<MyWidget> {
  final ExpansionTileController controller = ExpansionTileController();

  @override
  Widget build(BuildContext context) {
    return ExpansionTile(
      controller: controller,
    );
  }
}
```

Code after migration:

```dart
class _MyWidgetState extends State<MyWidget> {
  final ExpansibleController controller = ExpansibleController();

  @override
  void dispose() {
    controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return ExpansionTile(
      controller: controller,
    );
  }
}
```

## Timeline

Landed in version: 3.31.0-0.1.pre<br>
In stable release: 3.32

## References

API documentation:

* [`ExpansionTileController`][]
* [`ExpansibleController`][]
* [`ExpansionTile.controller`][]
* [`Expansible.controller`][]

Relevant issues:

* [Codeshare between ExpansionTile and its Cupertino variant][]
* [Deprecate ExpansionTileController in favor of ExpansibleController][]

Relevant PRs:

* [Introduce Expansible, a base widget for ExpansionTile][]
* [Deprecate ExpansionTileController][]

[`ExpansionTileController`]: https://api.flutter-io.cn/flutter/material/ExpansionTileController-class.html
[`ExpansibleController`]: https://api.flutter-io.cn/flutter/widgets/ExpansibleController-class.html
[`ExpansionTile.controller`]: https://api.flutter-io.cn/flutter/material/ExpansionTile/controller.html
[`Expansible.controller`]: https://api.flutter-io.cn/flutter/widgets/Expansible/controller.html

[Codeshare between ExpansionTile and its Cupertino variant]: https://github.com/flutter/flutter/issues/163552
[Deprecate ExpansionTileController in favor of ExpansibleController]: https://github.com/flutter/flutter/issues/165511
[Introduce Expansible, a base widget for ExpansionTile]: https://github.com/flutter/flutter/pull/164049
[Deprecate ExpansionTileController]: https://github.com/flutter/flutter/pull/166368