Unhandled Exception: This widget has been unmounted, so the State no longer has a context

You will encounter the following error when updating data with setState method after the display widget is disposed.

E/flutter (30970): [ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: This widget has been unmounted, so the State no longer has a context (and should be considered defunct).
E/flutter (30970): Consider canceling any active work during "dispose" or using the "mounted" getter to determine if the State is still active.
E/flutter (30970): #0      State.context. (package:flutter/src/widgets/framework.dart:909:9)
E/flutter (30970): #1      State.context (package:flutter/src/widgets/framework.dart:915:6)
E/flutter (30970): #2      _ProductsPageState._fetchProducts. (package:example/screens/product/products_screen.dart:55:9)
E/flutter (30970): #3      _rootRunUnary (dart:async/zone.dart:1436:47)
E/flutter (30970): #4      _CustomZone.runUnary (dart:async/zone.dart:1335:19)
E/flutter (30970): 
E/flutter (30970): 

To fix this issue, you need to check whether the widget is mounted. Then only call setState method if it is true.

if (mounted) { 
  setState (() => _products = []);
}