TextEditingController used after being disposed

Why This Happens

In Flutter, once a TextEditingController is disposed, accessing its text or other properties throws an error. This often happens when navigating away from a page and then an async callback tries to read the controller. Ensure proper lifecycle management.

The Problem

class _MyState extends State<MyWidget> {
  final _controller = TextEditingController();

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

  void onSubmit() async {
    await api.save(_controller.text);
    _controller.clear(); // May be disposed!
  }
}

The Fix

class _MyState extends State<MyWidget> {
  final _controller = TextEditingController();

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

  void onSubmit() async {
    final text = _controller.text;
    await api.save(text);
    if (mounted) {
      _controller.clear();
    }
  }
}

Step-by-Step Fix

1. 1

   Identify the error

   Look at the error about using a disposed TextEditingController. The controller was accessed after its dispose was called.

2. 2

   Find the cause

   Check for async operations that access the controller after the widget may have been disposed.

3. 3

   Apply the fix

   Store needed values before async gaps and check mounted before accessing the controller afterward.