Programmatically open and close ExpansionTile Widget.

I was building a Card which would be placed at the bottom of the screen, ExpansionTile is the child of this widget. When I click this card, the showModalBottomSheet() is called in OnExpansionChanged, however, I don't know how to close it. An open and close feature would be nice.

code reference: https://gist.github.com/ritvij-saxena/4726b3a834b8aa4afb7305eda2c970da
Live demo: https://dartpad.dev/4726b3a834b8aa4afb7305eda2c970da

Related to #7024
Currently we only have initiallyExpanded which does it initially and there is no way to close ExpansionTile afterwards programmatically #7024 (comment)

Should I be looking forward to this feature in the near future?

is there any way to close or open an ExpansionList in current version without loosing the animation?

For those looking for a solution before this has been implemented in Flutter:
You can simply copy the code of ExpansionTile and make a few changes.

I suggest renaming ExpansionTile and _ExpansionTileState to something else so the names don't cause confusion.
Make the previous _ExpansionTileState public (because we'll need to use a GlobalKey)
Add the method below. This will toggle the animation and state of ExpansionTileState when the new setting is different from the current one and changes nothing otherwise.

  void setExpanded(bool doExpand)
  {
    if ( doExpand != _isExpanded)
      _handleTap();      
  }

Now simply initialise ExpansionTile with a key and keep a reference to that key wherever you are using the Widget. Then you can call key.currentState.setExpanded(bool newExpandedState) when needed. ~~Or click here to see my implementation~~. Edit: view code here, this version has an openExpansion and closeExpansion method instead of the setExpanded above so keep that in mind.

The actual implementation in Flutter will probably differ though (as I don't believe they want to expose _ExpansionTileState).

For those looking for a solution before this has been implemented in Flutter:
You can simply copy the code of ExpansionTile and make a few changes.

I suggest renaming ExpansionTile and _ExpansionTileState to something else so the names don't cause confusion.

Make the previous _ExpansionTileState public (because we'll need to use a GlobalKey)

Add the method below. This will toggle the animation and state of ExpansionTileState when the new setting is different from the current one and changes nothing otherwise.
  void setExpanded(bool doExpand)
  {
    if ( doExpand != _isExpanded)
      _handleTap();      
  }
Now simply initialise ExpansionTile with a key and keep a reference to that key wherever you are using the Widget. Then you can call key.currentState.setExpanded(bool newExpandedState) when needed. Or click here to see my implementation.

The actual implementation in Flutter will probably differ though (as I don't believe they want to expose _ExpansionTileState).

Hello! Your link is broken.. Could you update it? Thanks)

For those looking for a solution before this has been implemented in Flutter:
You can simply copy the code of ExpansionTile and make a few changes.

I suggest renaming ExpansionTile and _ExpansionTileState to something else so the names don't cause confusion.

Make the previous _ExpansionTileState public (because we'll need to use a GlobalKey)

Add the method below. This will toggle the animation and state of ExpansionTileState when the new setting is different from the current one and changes nothing otherwise.
  void setExpanded(bool doExpand)
  {
    if ( doExpand != _isExpanded)
      _handleTap();      
  }
Now simply initialise ExpansionTile with a key and keep a reference to that key wherever you are using the Widget. Then you can call key.currentState.setExpanded(bool newExpandedState) when needed. Or click here to see my implementation.
The actual implementation in Flutter will probably differ though (as I don't believe they want to expose _ExpansionTileState).
Hello! Your link is broken.. Could you update it? Thanks)

Woops, my bad. Fixed it.

FWIW, it's far far more elegant to use ExpansionPanel which supports programmatically expanding and collapsing rather than changing keys to force an ExpansionTile to be rebuilt (which breaks the expansion/collapse animations).

its easy with this trick :

1- open expantion_tile.dart
2- in the state class and add this code :


  @override
  void didUpdateWidget(ExpansionTile oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.initiallyExpanded != widget.initiallyExpanded) {
      _handleTap();
    }
  }

and then you can use initiallyExpanded property as your own isExapnded and change it...!!

.
.
ExpansionTile(
        initiallyExpanded: _isExpanded,
.
.

and next :`

.
.
onPressed: () {
        print("hello");
        setState(() {
          _isExpanded = !_isExpanded;
        });
      },
.
.

remember restart your app for apply changes...
its worked for me.

its easy with this trick :

.
.
.

remember restart your app for apply changes... its worked for me.

Editing code from external libraries (such as Flutter), is HIGHLY discouraged.

When Flutter releases updates you're likely to get merge conflicts and/or the update will trample your local changes. Instead, you should make your changes a PR against flutter/flutter (of course adding tests and making sure your code is bug-free).

Contributing to flutter has a little bit of a learning curve but it's really not bad. See the contributing guide.

@override
  void didUpdateWidget(AppExpansionTile oldWidget) {
    if (oldWidget.isExpanded != widget.isExpanded &&
        (_controller.status != AnimationStatus.forward ||
            _controller.status != AnimationStatus.reverse)) {
      if (widget.isExpanded) {
        _controller.forward().then((value) {
          setState(() {
            _isExpanded = widget.isExpanded;
          });
        });
      } else {
        _controller.reverse().then((value) {
          setState(() {
            _isExpanded = widget.isExpanded;
          });
        });
      }
    }
    super.didUpdateWidget(oldWidget);
  }

I custom the method base on other answers

I custom the method base on other answers

Lol guys you all should really stop doing this. Updates will trample and break your changes-don't get in the habit of editing external libraries. It's extremally brittle.

If you all promise to stop editing external libraries I'll make a PR against ExpansionTile to support programmatic control.

It's been more than 2 years and nothing?

It's been more than 2 years and nothing?

Some PRs have been made but all have been closed. This comment in #95727 suggests a good approach though.

Solution: https://github.com/TreyThomas93/flutter-expansion-tile-demo

@ritvij-saxena

Hello @ritvij-saxena.
Did you solve this problem?
I got an issue like this.
I want your contact.
Thank you.

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.

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Programmatically open and close ExpansionTile Widget. #60387

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Programmatically open and close ExpansionTile Widget. #60387

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