flutter showdialog disable back button
showDialog(
context: context,
barrierDismissible: false,
builder: (BuildContext context) {
return WillPopScope(
onWillPop: () async => false,
child: AlertDialog(
title: Text('Title'),
content: Text('This is Demo'),
actions: <Widget>[
FlatButton(
onPressed: () => Navigator.pop(context),
child: Text('Go Back'),
),
],
),
);
},
);