@ehsanNazari145 Thanks for the PR! Kindly take a note of these things:
If you want to work on an issue, you first have to ask to be assigned to that issue via comments. Once you are assigned, only then you should start working on that issue.
While creating a PR, make sure to mention the issue that the PR is going to solve, like this: Closes #13
Also, this issue is only open for the participants of Codepeak, are you participating in it?
you have to wrap your main widget by SingleChildeScrollViwe.