mounted property

bool mounted
inherited

Whether this State object is currently in a tree.

After creating a State object and before calling initState, the framework "mounts" the State object by associating it with a BuildContext. The State object remains mounted until the framework calls dispose, after which time the framework will never ask the State object to build again.

It is an error to call setState unless mounted is true.

Implementation 

bool get mounted => _element != null;