Flutter android 工作室的构造函数错误。 一直显示错误

Question

enter image description here When I try to create a new class in the library of flutter, inside the class the constructor shows error

Answer 1

The problem is that you have your parameters as optionally named, which means the caller can decide not to pass q or a , but you also marked them as non-nullable. Add the required keyword before your parameters to make sure they're passed in and are non-null, or add a default.

Also, in the future:

• Please copy-paste your code instead of using an image. This lets us quickly copy-paste it into our IDEs and find any errors.
• Please post the error you're getting. Errors are your friends, they tell you what's wrong, and they'll help us figure out how to help you.