GETX Error: Conditions must have a static type of 'bool'

Question

Firstly, I am using getx state management. There may be delays while receiving data from the API. So I tried to use circular progress indicator but got error.

error: Conditions must have a static type of 'bool'. (non_bool_condition at [app] lib\screens\app\app.dart:56)

import 'package:get/get.dart';

class LoadingController extends GetxController {
  late RxBool isLoading;

  void getLoading() {
    isLoading = true.obs;
    Future.delayed(const Duration(seconds: 2), () {
      isLoading = false.obs;
    });
  }

  @override
  void onInit() {
    getLoading();
    super.onInit();
  }
}

All pages consist of stateless widgets

LoadingController loading = Get.put(LoadingController());

child: loading.isLoading
                      ? Center(
                          child: CircularProgressIndicator(),
                        )
                      : Container(
                          decoration: BoxDecoration(
                            color: cCardColor,
                            borderRadius: BorderRadius.circular(8.r),
                          ),

I don't want to turn the pages statefull but I couldn't find a way

Solution

This error happened because you defined an observable variable but used and assigned value to it like a normal variable

You used an Observable variable so you have to use the Obx or GetX widget to rebuild UI.

Change UI codes like this :

LoadingController loading = Get.put(LoadingController());

child: Obx(()=>loading.isLoading.value
                      ? Center(
                          child: CircularProgressIndicator(),
                        )
                      : Container(
                          decoration: BoxDecoration(
                            color: cCardColor,
                            borderRadius: BorderRadius.circular(8.r),
                          ),
    ),

Also, there is an issue in the controller. Please check the below code.

import 'package:get/get.dart';

class LoadingController extends GetxController {
  RxBool isLoading = false.obs;

  void getLoading() {
    isLoading(true);
    Future.delayed(const Duration(seconds: 2), () {
      isLoading(false);
    });
  }

  @override
  void onInit() {
    getLoading();
    super.onInit();
  }
}

Comments

[regenin]

thank you for help but i don't understand. what is difference between isLoading = true.obs; and isLoading(true); Actually I have not come across it used in this way generally.

[mahmoud_eslami]

Regarding the get x document we can update the observable value with variable_name(new_value);. I don't know exactly but I think there is another method call variable_name.update(). So when you assign a new value like isLoading = true.obs; the observable variable doesn't update.