Flutter and GetxController - How to manage state unreliability?

Question

I currently have many problems in my app with the get package for Flutter (https://pub.dev/packages/get) and the following state scenario:

For example I have a GetxController UserController. I need this controller in different Widgets, so I initialize it with Get.put() in the first widget and for the other child widgets I'll call it with Get.find(). That works.

But: I have some widgets that sometimes load before the controller got initialized and sometimes after. So I get many "UsersController" not found errors. Maybe there exists some workaround for this problem?

score 6 · Answer 1 · answered Nov 15 '20 at 05:21

6

You could initialize your UsersController class using a Bindings class, prior to the start of your app.

Example

class UsersController extends GetxController {
  static UsersController get i => Get.find();
  int userId = 5;
}

class UsersBinding extends Bindings {
  @override
  void dependencies() {
    Get.put<UsersController>(UsersController());
  }
}

void main() async {
  UsersBinding().dependencies();
  runApp(MyApp());
}

Done this way your UsersController is guaranteed to be available everywhere in your app, prior to any Widgets loading.

class MyHomePage extends StatelessWidget {
  final UsersController uc = Get.find();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('GetX Bindings'),
      ),
      body: Center(
        child: Obx(() => Text('userId: ${uc.userId}')),
      ),
    );
  }
}

answered Nov 15 '20 at 05:21

Baker

24,730
11
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106

Is there any difference between what you've shown here and just putting `Get.put(UsersController());` right before `runApp(MyApp());`? Is the `Bindings` extension necessary? – Clifton Labrum Aug 27 '22 at 18:53
1

@CliftonLabrum This is the only thing I could find from the creator of the GetX project on why we'd use Bindings: https://github.com/jonataslaw/getx/issues/945#issuecomment-751182606 i.e. It's not necessary, but just organizes your Controller dependencies into a single spot that's (potentially) easier to switch between mocks / production code & naming is perhaps more intuitive ("Bindings"/"dependencies" is easier to guess its impact than "Get.put", which is more abstract) for collaborators who are unfamiliar with GetX. – Baker Aug 28 '22 at 21:04
I applied what I learned from your answer, as well as the use of getters, to make controller references really convenient: https://stackoverflow.com/a/73515232/1142348 – Clifton Labrum Aug 29 '22 at 14:53
@CliftonLabrum Thanks for note & link to your question. I added an answer to your question there, to address the other responses, which I believe are incorrect about placement of `Get.put` statements. It *should* be done within `build()` unless we're looking for persistence. – Baker Aug 29 '22 at 19:00

score 4 · Answer 2 · answered Nov 13 '20 at 17:13

4

try to add

GetMaterialApp(
  smartManagement: SmartManagement.keepFactory,
)

so that it can store factory of those instanse

or make sure add permanent

Get.put<Repo>(Repo(), permanent: true);

so that it never get deleted from memory

answered Nov 13 '20 at 17:13

GJJ2019

4,624
3
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22

1

This will not work, because I have some widgets which are running before the controller itself was loaded. But for some situations I need this widget after the controller was loaded. In fact I need something like a condition: `Get.isInit(UsersController()) ? Get.find() : Get.put(UsersController)` .... – Vueer Nov 14 '20 at 06:58

score 1 · Answer 3 · answered Apr 17 '21 at 08:24

1

if u need to check class is initialized, u most keep the class in memory with permanent:trueand set tag:'anything you want for check this object' property in Get.put function, and now u can check

bool Get.isRegistered<className>(tag: 'TagInPut')

answered Apr 17 '21 at 08:24

Mohsen Haydari

550
5
20

score 0 · Answer 4 · answered Jan 30 '21 at 07:36

0

If there's no specific reason, you can just call Get.put(UserController()) at main function and wrap material app with GetMaterialApp.

answered Jan 30 '21 at 07:36

hyobbb

332
1
9

score -1 · Answer 5 · answered Nov 13 '20 at 17:09

if you are using get to provide an instance of something across your app meaby https://pub.dev/packages/get_it could help you more. just be sure that you use allowReassignment==true so you can update your instance if you want save a full new controller, but if you want to use the same always get_it is perfect for you

Flutter and GetxController - How to manage state unreliability?

5 Answers5

Example

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