Change AppBar title value on carousel change without setstate - flutter

Question

I'm developing a gallery app looking like whatsapps photo gallery. I want the appbar title change when my carousel slider changes. I tried it with setstate but because I show the carouselslider in a showdialog, it doesn't work and I think it can be cause performance issues. I use getx in the project and is there any way to do it without setstate?
Here is my AppBar widget
showGeneralDialog(
context: context,
barrierDismissible: true,
barrierLabel: MaterialLocalizations.of(context)
.modalBarrierDismissLabel,
barrierColor: Colors.black45,
transitionDuration:
const Duration(milliseconds: 200),
pageBuilder: (BuildContext buildContext,
Animation animation,
Animation secondaryAnimation) {
return Dismissible(
direction: DismissDirection.vertical,
key: const Key('key'),
onDismissed: (_) => Navigator.of(context).pop(),
child: Scaffold(
appBar: AppBar(title: Text(photoSender)),
And body of the scaffold is a carouselsliderbuilder, so when the carousel changes, I want the photoSender variable to change.
Any ways to do this?

Answer 1

Declare you photoSender variable as Rx<String>:
final photoSender = Rx<String>("");
Wrap your Text widget with Obx/GetX:
appBar: AppBar(title: Obx(()=>Text(photoSender.value))),
Whenever your photoSender variable`s value changes, it will automatically update the text in your app bar.
To update the value:
photoSender.value = "John";