How to close an Alert dialog without a button in FLUTTER - flutter

Question

I want to show a circle indicator when the user presses the login button. But sometimes an error can occur such as a Wrong email or wrong password. In that case, the circle indicator should be stopped and the error message should be shown. There is no button in circle indicator alert dialog. I want it to automatically close when an error found
onPressed: () async {
AuthResult user;
progressIndi();
try {
user = await _auth.signInWithEmailAndPassword(email: email, password: pass);
} catch (err) {
finderror(err.code);
}
finderror function will find the error message to show.
progressIndi() function will show the alert dialog. I tried to implement it with stacks. But it's only showing changes when I close the dialog box and press the login button again.
void progressIndi() {
showDialog(
barrierDismissible: false,
context: context,
builder: (BuildContext context) {
return IndexedStack(
index: isError,
children: <Widget>[
AlertDialog(
content: new Row(
children: [
CircularProgressIndicator(),
Container(
margin: EdgeInsets.only(left: 5),
child: Text(" Loading")),
],
),
),
AlertDialog(
title: Text("Error Found"),
content: Text(errorMessage),
actions: <Widget>[
// usually buttons at the bottom of the dialog
new FlatButton(
child: new Text("Try Again"),
onPressed: () {
Navigator.of(context).pop();
isError = 0;
},
),
],
),
],
);
},
);
}
I know that alert dialog can be closed using the button and Navigator.of(context).pop() .
Please, anyone, give me a hint to close the alert dialog from outside without a button.

Answer 1

You can remove the dialog when an error occurs by calling Navigator.of(context).pop() just after the exception occurs and then show another dialog for error. Hope this helps.
AuthResult user;
progressIndi();
try {
user = await _auth.signInWithEmailAndPassword(email: email, password: pass);
} catch (err) {
//Use pop here.
Navigator.of(context).pop();
//make findError open another dialog.
finderror(err.code);
}