[gspencergoog]

Description

We've had some feedback that people would like to be able to invoke actions when they are not in the context of keyboard input (from a mouse click, etc.).

The original design was oriented towards invoking actions from widgets, and
having those actions act in the context of the widget. Teams have been using
actions, and found several limitations in that design that needed to be
addressed:

1. They were unable to invoke actions from outside of the widget hierarchy.
   Examples of this include processing a script of commands, and some undo/redo
   systems.
2. The mapping between shortcut key to Intent and then to Action wasn't
   always clear, since the data structures were mapping LogicalKeySet =>
   Intent and then LocalKey => ActionFactory. The new mapping is still
   LogicalKeySet => Intent but then it maps Type (Intent type) =>
   Action, which more direct and readable, since the type of the intent is
   written in the mapping.
3. If the key binding for an action was in another part of the widget hierarchy,
   it was not always possible for the Intent to have access to the state
   necessary to decide if the intent/action should be enabled or not.

Here are the changes made to address these problems:

1. The FocusNode argument to Action.invoke and Actions.invoke was removed.
2. The Map<LocalKey, ActionFactory> that was given to the Actions widget is
   now a Map<Type, Action<Intent>> (the type is the type of the Intent).
3. The isEnabled method was moved from the Intent to the Action class.
4. Invoking an action no longer creates a new instance of the Action.
5. The Action class is now a generic (Action<T extends Intent>) for better
   type safety.
6. A LocalKey is no longer an argument to the Intent constructor.
7. The Action class may now be listened to for changes in state.
8. The OnInvokeCallback used by CallbackAction no longer takes a FocusNode
   argument.
9. The LocalKey argument to CallbackAction has been removed.
10. The ActionDispatcher.invokeAction signature has changed to not accept an
    optional FocusNode, but instead take an optional BuildContext.
11. The LocalKey static constants (named key) in Action subclasses have been
    removed.
12. The Action.invoke and ActionDispatcher.invokeAction methods now return
    the result of invoking the action.
13. The ActionFactory typedef has been removed, as it is no longer used.

There is a design doc for the changes in the PR: https://flutter.dev/go/actions-and-shortcuts-design-revision

Tests

• Modified existing tests to verify that the correct context is being passed.

Related Issues

• Fixes Update Actions API to not need FocusNodes and improve Intent->Action mapping #53276

Breaking Change

• Yes, this is a breaking change for anyone using Actions, and probably Shortcuts too.
  • The signature for Action.invoke has changed significantly, as has the Action constructor.
  • The RequestFocusAction now requires the use of a RequestFocusIntent.
  • The signature for onInvoke property of the CallbackAction has also changed.
  • The invokeAction signature on the ActionDispatcher has changed.
  • The map for actions on the Actions widget is now a Map<Type, Action<Intent>>.
  • Invoking an action doesn't create a new instance of the action.

[goderbauer]

The new API is pretty nice!

[gspencergoog]

@goderbauer, Thanks for your review!

I think this is ready for another look.

[goderbauer]

LGTM

[goderbauer]

LGTM