Flutter/Dart - Transparent Background to CircularProgressIndicator on a Loading Future? - flutter

Question

At the moment I get a white background with a spinning CircularProgressIndicator when I swipe to a new route. The new route has a Future that fetches data from a HTTP Post. Instead I'd like the background of the original page to remain behind the spinner until the future completes and the transition happens. So how do I make the spinners' background transparent instead of white? Here's the code to the future which I assume is where the spinner gets triggered;
FutureBuilder<List<ReplyContent>> replyStage({String replyid, String replytitle}) {
return new FutureBuilder<List<ReplyContent>>(
future: downloadReplyJSON(),
builder: (context, snapshot) {
if (snapshot.hasData) {
List<ReplyContent> replycrafts = snapshot.data;
return StageBuilderVR(replycrafts, replytitle);
} else if (snapshot.hasError) {
return Text('${snapshot.error}');
}
return CircularProgressIndicator();
},
);
}
And here's the code which swipes to the future;
onSwipeUp: () {
Navigator.of(context).push(_createRoute());
}
And the code for the PageRouteBuilder:
Route _createRoute() {
return PageRouteBuilder(
opaque: false,
pageBuilder: (context, animation, secondaryAnimation) => ReplyHome(),
transitionsBuilder: (context, animation, secondaryAnimation, child) {
var begin = Offset(0.0, 1.0);
var end = Offset.zero;
var curve = Curves.ease;
var tween = Tween(begin: begin, end: end).chain(CurveTween(curve: curve));
return SlideTransition(
position: animation.drive(tween),
child: child,
);
},
);
}

Answer 1

You can use showDialog to open a dialog which will open a transparent background with the AlertDialog, You can return your own stateful widget. Instead of streamBuilder just use future Builder.
try following code:
void uploadAndShowProgress() async {
await showDialog(
context: context,
builder: (context) {
return StreamBuilder(
stream: uploadFile(),
builder: (context, snapshot) {
if (snapshot.hasData) {
StorageTaskEvent event = snapshot.data;
final _snapshot = event.snapshot;
_progress = _snapshot.bytesTransferred / _snapshot.totalByteCount;
} else {
//* pop when there's no data or error...
Navigator.pop(context);
}
if (snapshot.hasError) {
SnackbarWidget.showSnackbar(
content: Text(snapshot.error.toString()), context: context);
}
return AlertDialogWidget(progress: _progress);
},
);
},
);
}

Answer 2

this function pushes route with transparent background
onPressed: () {
Navigator.of(context).push(
PageRouteBuilder(
opaque: false,
pageBuilder: (_, __, ___) {
return MyTransperentRoute();
},
),
);
}
so in your CircularProgressIndicator page you can change background color of the root Widget like color: Colors.transperent or a plain Container without any color set will achieve the effect you need
class MyTrnsperentPage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Container(
child: const Center(
child: CircularProgressIndicator(),
),
);
}
}
see the working code on dartpad here

Answer 3

Stack(
children: <Widget>[
Opacity(
opacity: _isLoading ? 1.0 : 0,
child: CircularProgressIndicator(),
),
],
);

Answer 4

In the end, I created a dummy Page that graphically mirrored the previous page with all the graphic elements of the previous page and none of the code. I put that in place of the CircularProgressIndicator. I don't know if it's ideal, but it seems to work well.
FutureBuilder<List<ReplyContent>> replyStage({String replyid, String replytitle}) {
return new FutureBuilder<List<ReplyContent>>(
future: downloadReplyJSON(),
builder: (context, snapshot) {
if (snapshot.hasData) {
List<ReplyContent> replycrafts = snapshot.data;
return StageBuilderVR(replycrafts, replytitle);
} else if (snapshot.hasError) {
return Text('${snapshot.error}');
}
return DummyPage();
},
);
}