Flutter: Google Maps StateError (Bad state: Future already completed) - google-maps

Question

I'm trying to display Google maps inside a dialog box and for the first time it pops up as expected, however the second time it throws and exception: StateError (Bad state: Future already completed).
Completer<GoogleMapController> _controller = Completer();
_displayDialog(){
Alert(
context: context,
style: alertStyle,
title: "Here are your results:",
content: Column(
children: <Widget>[
Container(
width: 200.0,
height: 200.0,
child: GoogleMap(
//mapType: MapType.hybrid,
initialCameraPosition: _kGooglePlex,
onMapCreated: (GoogleMapController controller) {
_controller.complete(controller); //throws here in this line
},
),
),
],
),
Here is a gif to summarize whats happening
Im using rflutter_alert: ^1.0.3 for the dialog box,
and google_maps_flutter: ^0.5.21+15 for Maps.
Thanks in advance!

Answer 1

this verifies if previously I already called "completer ()" if so, you don't need to call "completer ()" again, and just skip it in your code
onMapCreated: (GoogleMapController controller) {
if (!_controller.isCompleted) {
//first calling is false
//call "completer()"
_controller.complete(controller);
}else{
//other calling, later is true,
//don't call again completer()
}
}

Answer 2

I think that the problem is because you are trying to complete a Completer twice which is not allowed. What I did bellow was to create a new Completer each time you call _displayDialog().
_displayDialog(){
Completer<GoogleMapController> _controller = Completer();
Alert(
context: context,
style: alertStyle,
title: "Here are your results:",
content: Column(
children: <Widget>[
Container(
width: 200.0,
height: 200.0,
child: GoogleMap(
//mapType: MapType.hybrid,
initialCameraPosition: _kGooglePlex,
onMapCreated: (GoogleMapController controller) {
_controller.complete(controller); //throws here in this line
},
),
),
],
),