Flutter GetX Obx not updating text on button press

Question

Below I have a very simple GetX project that should basically load some data on button press asynchronously. However, I would like the button to change from 'PRESS ME' to 'LOADING' whilst the data is fetched. I cannot get my head around why the widget is not rebuilt when I change the observable status variable. Am I missing a fundamental concept here? The widget clearly does get re-drawn after the async method updateDetails finishes, but not when I change 'status' within the method...? Many thanks.

void main() async {
  runApp(TestApp());
}

class TestApp extends StatelessWidget {
  const TestApp({super.key});

  @override
  Widget build(BuildContext context) {
    return GetMaterialApp(
      theme: appTheme,
      home: TestWidget(),
    );
  }
}

class TestController extends GetxController {
  var status = 'PRESS ME'.obs;
    
  updateDetails() async {
    print('Loading');
    status('LOADING');
    sleep(1.seconds);
    print('Finished');
    status('PRESS ME');
  }
}

class TestWidget extends StatelessWidget {
  TestWidget({super.key});
  final TestController controller = Get.put(TestController());

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: TextButton(
          onPressed: () {
            controller.updateDetails();
          },
          child: Obx(() {
            print('Redrawing text');
            return Text(controller.status.value);
          }),
        ),
      ),
    );
  }
}

Ivo · Accepted Answer · 2025-03-04 12:52:52Z

1

sleep is not the way to wait in Flutter. Use awaiting a Future.delayed instead. So instead of

sleep(1.seconds);

do

await Future.delayed(1.seconds);

instead

answered Mar 4 at 12:52

Ivo

23.7k2 gold badges32 silver badges41 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Pinocchio Mar 4 at 12:58

Thanks Ivo, amazingly quick and helpful answer - just got back into Flutter, I had forgotten about this. Works as expected, after staring at it for hours! I am still puzzled WHY sleep won't work though?

Ivo Mar 4 at 13:01

I'm not sure but I think sleep literally pauses the main thread so nothing can happen during that time

Alok Kumar Maurya · Accepted Answer · 2025-03-09 05:31:20Z

0

As per you imolementation, it is all correct and data ia being updated. But you cannot see the update on the UI, this is happening because you varibales value is being updated too frequently, that is in a very sort time, it changes the value

   print('Loading');
    status('LOADING');
    sleep(1.seconds);
    print('Finished');
    status('PRESS ME');

it will first assign the Loading then i suppose to wait for 1 second which is not correct and the issue is in this line only, since it will not wait for 1 second, so the value of the variable will again change to Finished and this is the reason why you cannot see the UI change.

To make flutter wait for some time you need to use the Future function.

await Future.deleayed(1.second);

edited Mar 9 at 5:31

answered Mar 9 at 5:30

Alok Kumar Maurya

13 bronze badges

Collectives™ on Stack Overflow

Flutter GetX Obx not updating text on button press

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related