I've just do a college task, and yeah they provide the source code which I need to re-write it on my own IDE, but after that there is lot of problems with "can not null", after a bit of research then I realize that the flutter SDK version in my task example is 2.2.3 which is lower than mine 2.2.5
Well, when I try to change my flutter version to 2.2.3 too in Flutlab.io the error seem to be decreased and nomore "can not null" error message.
So, I decide to downgrade my flutter version in my local machine too. Here are my step to do that :
# check first my current version flutter --version # change flutter channel, but mostly it will on stable by default flutter channel stable # the most important things, fetch any new thing from flutter repo git pull # the use downgrade command, it should download some of component/dependencies needed for flutter 2.2.3 flutter downgrade 2.2.3 # after that you may see error "There is no previosly recorde" but it's OK # run flutter doctor the you may see that your flutter version was changed flutter doctor # just to make sure, check agai our flutter version flutter --version
I don't know why it works ?