dart - Flutter, what is the ":"?

Question

This question already has answers here: question from:https://stackoverflow.com/questions/65652100/flutter-what-is-the

Answer 1

ListState._({...})

This is a private named constructor that means you can't instantiate this class object from outside the current library.

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const ListState.loading() : this._();

This is also a named constructor (not private though) and here this._()) is simply delegating the call to the private named constructor.