registerField method

Implementation

void registerField(String name, FormBuilderFieldState field) {
  // Each field must have a unique name.  Ideally we could simply:
  //   assert(!_fields.containsKey(name));
  // However, Flutter will delay dispose of deactivated fields, so if a
  // field is being replaced, the new instance is registered before the old
  // one is unregistered.  To accommodate that use case, but also provide
  // assistance to accidental duplicate names, we check and emit a warning.
  final oldField = _fields[name];
  assert(() {
    if (oldField != null) {
      debugPrint(
        'Warning! Replacing duplicate Field for $name'
        ' -- this is OK to ignore as long as the field was intentionally replaced',
      );
    }
    return true;
  }());

  _fields[name] = field;
  field.registerTransformer(_transformers);

  if (widget.clearValueOnUnregister || (_instantValue[name] == null)) {
    _instantValue[name] = field.initialValue ?? initialValue[name];
  }

  field.setValue(_instantValue[name], populateForm: false);
}