refactor: Loadable mixin no longer declares onMount and onRemove

[st-pasha]

Description

Loadable mixin is currently used for 2 classes: Game and Component. Its purpose is to provide the caching layer for the future returned by the onLoad() method. Having empty methods onMount() / onRemove() in that mixin does not fit its overall purpose. (Plus, in general, the purpose of any mixin is to add some additional concrete functionality into an existing class).

In addition to the scope mismatch, these methods perform similar yet not quite the same function in Game and Component. Having these methods declared directly within Game and Component allows to document them more precisely, and help the user understand their functionality/purpose better.

Checklist

• The title of my PR starts with a Conventional Commit prefix (fix:, feat:, docs: etc).
• I have read the Contributor Guide and followed the process outlined for submitting PRs.
• I have updated/added tests for ALL new/updated/fixed functionality.
• I have updated/added relevant documentation in docs and added dartdoc comments with ///.
• I have updated/added relevant examples in examples.

Breaking Change

• No, this is not a breaking change.

Related Issues

Closes #1210

[st-pasha]

Note: I wasn't quite able to figure out the difference between onMount and onAttach for the Game class -- which I guess only stresses the need for clear and precise documentation for that function.

[spydon]

Note: I wasn't quite able to figure out the difference between onMount and onAttach for the Game class -- which I guess only stresses the need for clear and precise documentation for that function.

onAttach is when the Flutter widget is attached to the Flutter widget tree, onMount is when the component is added to a component tree (after onLoad).

[spydon]

Lgtm

[st-pasha]

onAttach is when the Flutter widget is attached to the Flutter widget tree, onMount is when the component is added to a component tree (after onLoad).

Exactly: this is where it gets confusing. I understand onMount for the Component class. But the Game class is a different story. So the question is: what is onMount in the Game class, and how is it different from the onAttach handler?

The situation with onRemove / onDetach is similar, only I believe the former is called before the game is removed from the widget, while the latter called after. We should consider at some point to rename them to improve clarity. For example: onBeforeDetach / onAfterDetach.

[spydon]

Exactly: this is where it gets confusing. I understand onMount for the Component class. But the Game class is a different story. So the question is: what is onMount in the Game class, and how is it different from the onAttach handler?

Yeah, I see the confusion. We should remove onMount and onRemove from the game mixin (I must have accidentally put them there) and in FlameGame we should call onMount from onAttach and onRemove from onDetach probably. Since a game can be added as a child to another component, there will still be a difference to them.