deactivate method

  1. @override
void deactivate()
override

Called when this object is removed from the tree.

The framework calls this method whenever it removes this State object from the tree. In some cases, the framework will reinsert the State object into another part of the tree (e.g., if the subtree containing this State object is grafted from one location in the tree to another due to the use of a GlobalKey). If that happens, the framework will call activate to give the State object a chance to reacquire any resources that it released in deactivate. It will then also call build to give the State object a chance to adapt to its new location in the tree. If the framework does reinsert this subtree, it will do so before the end of the animation frame in which the subtree was removed from the tree. For this reason, State objects can defer releasing most resources until the framework calls their dispose method.

Subclasses should override this method to clean up any links between this object and other elements in the tree (e.g. if you have provided an ancestor with a pointer to a descendant's RenderObject).

Implementations of this method should end with a call to the inherited method, as in super.deactivate().

See also:

  • dispose, which is called after deactivate if the widget is removed from the tree permanently.

Implementation

@override
void deactivate() {
  for (final NavigatorObserver observer in _effectiveObservers) {
    NavigatorObserver._navigators[observer] = null;
  }
  super.deactivate();
}