deactivate method

@override @protected @mustCallSuper void deactivate()

The framework calls this method whenever it removes this State object from the tree.

Implementation

@override
@protected
@mustCallSuper
void deactivate() {
  /// The framework calls this method whenever it removes this [State] object
  /// from the tree. Subclasses should override this method to clean up any links between
  /// this object and other elements in the tree.

  // Indicate this State object is deactivated.
  deactivated = true;

  // Unregisters the given observer.
  WidgetsBinding.instance.removeObserver(this);

  // No 'setState()' functions are allowed to fully function at this point.
  _setStateAllowed = false;

  for (final con in controllerList) {
    //
    con.deactivate();
    // Pop the State object from the controller
    con._popStateFromSetter(this);
  }

  super.deactivate();

  // Remove from the list of StateX objects present in the app!
  _removeFromMapOfStates(this);

  _setStateAllowed = true;

  // In some cases, if then reinserted back in another part of the tree
  // the build is called, and so setState() is not necessary.
  _setStateRequested = false;
}