Close loading dialog in FutureBuilder - flutter

Question

I am using Futurebuilder in flutter and having issue while closing the showDialog
Widget build(BuildContext context) {
return Scaffold(
appBar: PreferredSize(
preferredSize: Size( 50.0),
body: FutureBuilder(
future: widget.getAutoCompleteData(),
builder: (context, snapshot) {
if (snapshot.hasData) {
Navigator.of(context).pop();
} else if (snapshot.hasError) {
} else {
LoadingDialog.showLoadingDialog(context, _scaffoldKey);
}
return Center(
child: Container(child: Text("sds"),),
);
}));
}
Getting below error when screen loads
package:flutter/src/widgets/navigator.dart': Failed assertion: line 5013 pos 12: '!_debugLocked': is not true

Answer 1

Change this
FutureBuilder(
future: widget.getAutoCompleteData(),
builder: (context, snapshot) {
if (snapshot.hasData) {
Navigator.of(context).pop();
} else if (snapshot.hasError) { //here this is empty
} else {//remove else statement
LoadingDialog.showLoadingDialog(context, _scaffoldKey);
}
return Center(
child: Container(child: Text("sds"),),
);
})
To This
FutureBuilder<List<Post>>(
future: _dataFetcher.getPosts(),
builder: (context, snapshot) {
if (snapshot.connectionState == ConnectionState.waiting) {
return Center(
child: CircularProgressIndicator(),
);
}
if (snapshot.hasError) {
return LoadingDialog.showLoadingDialog(context, _scaffoldKey);
}
return Center(child: Text('${snapshot.data![0].title}'));
},
)

Answer 2

It may be caused by the re-entrant of the Navigator (you can check the answer here: Error thrown on navigator pop until : “!_debugLocked': is not true.”
)
Or, maybe you don't want to use FutureBuilder. The FutureBuilder is meant to stay in the same widget/page and show different screens when future data is not ready. If you want to push a loading dialog and close it when data is ready, you can just simply use a Future function
Future pressTheButton(context) async {
LoadingDialog.showLoadingDialog(context, _scaffoldKey); // showDialog here
final data = await getAutoCompleteData(); // await the data
Navigator.of(context).pop(); // pop the loading dialog
// return your data or error
// or rebuild the current widget with the data
}