The lower bound of "sdk: '>=2.1.0 <3.0.0'" must be 2.12.0 or higher to enable null safety

Question

Hi how this problem solvedenter image description here

I added the widget "dropdown_formfield: ^0.1.4" to my project and it showed this error How can I fix this problem please help. This package : https://pub.dev/packages/dropdown_formfield

Holocaine

Answer 1

You must update your flutter/dart version like this (in your pubspec.yaml):

environment:
  sdk: ">=2.18.0"

Be prepared to make changes on your project/code due null safety

Or seek to find a lower version of that "dropdown_formfield" that can be supported by your actual flutter/dart version.

Stefaniastefanie

Answer 2

Try upgrading your constraint on cupertino_icons: flutter pub add cupertino_icons:^1.0.6

Neotype

Answer 3

write

any keyword

instead of ^0.1.4

Mascara

any is not the case as it download the current latest stable version of plugin. So. at this point requires dart version > 2.1 – Stefaniastefanie

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Answer 4

I tried to add this package https://pub.dev/packages/slimy_card but I faced this

Because ptc_flutter depends on slimy_card any which doesn't support null safety, version solving failed.

The lower bound of "sdk: '>=2.1.0 <3.0.0'" must be 2.12.0 or higher to enable null safety. For details, see https://dart.dev/null-safety

Vshaped

Answer 5

Faced the same problem running a test code as part of udemy course from GitHub repo mi_card_flutter

As you can see, my flutter version is 3.16.9

flutter --version
Flutter 3.16.9 • channel stable • https://github.com/flutter/flutter.git

And my dart version is 3.2.6

  dart --version
Dart SDK version: 3.2.6 (stable) (Wed Jan 24 13:41:58 2024 +0000) on "macos_x64"

What I noticed is this code was updated 3 years ago and my Flutter and Dart versions were new. So I have made couple of updates.

Update below in the pubspec.yaml

environment:
  sdk: '>=3.2.6 <4.0.0'

After this, when I pulled dependencies using Get Depenencies on main.dart in Android Studio, saw below errors

    The current Dart SDK version is 3.2.6.
    
    Because mi_card depends on cupertino_icons >=0.1.1 <1.0.1 which doesn't support null safety, version solving failed.
    
    The lower bound of "sdk: '<2.0.0 or >=2.0.0-dev.28.0 <3.0.0'" must be 2.12.0 or higher to enable null safety.
    For details, see https://dart.dev/null-safety

You can try the following suggestion to make the pubspec resolve:
* Try upgrading your constraint on cupertino_icons: flutter pub add cupertino_icons:^1.0.6

As you can see in the error its suggesting to use the 1.0.6 version.

So change which I had to do this to upgrade the version of cupertino_icons dependency from 0.1.2 to below

cupertino_icons: ^1.0.6

And it worked perfectly fine.

Factitious