Flutter null safety checks

Question

flutter seems to be switching between null safety checks and nonnull safety checks causing dozens of issues.

Running: flutter clean remove all null check errors, but when I run: flutter pub get the null errors return?

Really confusing, my dart sdk:

environment:sdk: ">=2.11.6 <3.0.0"

I think dart was updated recently to include null checks and it seems to be causing loads of problems for me, I have corrected the null errors before anyone suggests this and when I run flutter clean the null error check I have implemented cause errors.

lib/screens/add_new_location_note_screen.dart:23:8: 
Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.12 or higher. Place? _pickedLocation;

Now I have changed the minimum sdk to

environment: sdk: ">=2.12.0 <3.0.0"

ran: flutter clean

and the errors again disappear now running: flutter pub get

the null errors checks return ???

refer https://stackoverflow.com/a/66636686/5106574 – Jitesh Mohite Mar 15 '21 at 11:01 — Jitesh Mohite, Mar 15 '21 at 11:01

Lee3 · Accepted Answer · 2020-12-26T19:49:21.507

2

You must set the SDK constraints like so:

environment: sdk: ">=2.12.0-0 <3.0.0"

Currently, the 2.12 SDK is in pre-release (beta), requiring the use of the -0 to signify the pre-release version to use.

edited Dec 26 '20 at 19:49

answered Dec 26 '20 at 19:00

Lee3

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I updated the answer to give a brief explanation of why this is required. – Lee3 Dec 26 '20 at 19:50

Flutter null safety checks

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