this is my complete code...

``````import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:get/get.dart';

class DialogHelper{
//show error dialog
static void showErrorDialog({String title='error',String description='Something went wrong'})
{
Get.dialog(
Dialog(
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
ElevatedButton(onPressed: () {
if (Get.isDialogOpen) Get.back();
},
child: Text('okay')),
],
),
),
),
);

}
}
``````

And I got this error

19:25: Error: A value of type 'bool?' can't be assigned to a variable of type 'bool' because 'bool?' is nullable and 'bool' isn't. if (Get.isDialogOpen) Get.back();

I got error on the line if condition Get.isDialogOpen

### Solution 1: Loïc Fonkam

You are getting that error because the getter `isDialogOpen` returns an Optional. This means the return value can either be a `true`, `false` or a `null`. But, since if-conditions can only work with Booleans, the SDK tells you there will be an error if `isDialogOpen` returns a null.

So to fix that, either you tell the compiler that you are sure your getter will never return a null, or you have to give a default value in case a null is returned from `.isDialogOpen`. We do it like this respectively;

1-

``````  Get.isDialogOpen! \\ this means you are sure a null can't be returned
``````

2-

`````` Get.isDialogOpen ?? false \\ this means incase a null is returned use false
``````

Note: If you use number 1, and a null is eventually returned, your code will crash at run-time. To avoid that, you can tell the compiler to call the `isDialogOpen` only if it has been initialized. i.e.

``````Get?.isDialogOpen ?? false \\If isDialogOpen is not initialized, false will be used
``````