Currently, I know the method of hiding the soft keyboard using this code, by onTap methods of any widget.
onTap
FocusScope.of(context).requestFocus(new
Wrap whole screen in GestureDetector as
GestureDetector
new Scaffold( body: new GestureDetector( onTap: () { // call this method here to hide soft keyboard FocusScope.of(context).requestFocus(new FocusNode()); }, child: new Container( - - - ) )