[menubar] Support keyboard shortcuts

[stuartmorgan-g]

The current menu support doesn't allow for keyboard shortcuts, which is definitely necessary.

(It might also be useful to have some kind of generic way for widgets to handle keyboard shortcuts, but that would need more thought about how focus works in a desktop Flutter environment.)

[rodydavis]

This is also really important for iPad development. It is now common for there to be a connected keyboard in iOS. And holding down the command key reveals all available shortcuts for an app.

[stuartmorgan-g]

This is primarily tracking adding functionality to the menubar plugin, which is specific to this project. If you want keyboard shortcut support in Flutter itself, you'd want to file (or vote for) a request in the Flutter project's issue tracker.

[rodydavis]

Oh for sure, just thought it was still relevant to mention as there maybe some overlap.

[rodydavis]

Is there anything that could be added on macos given the MacOS Catalina release and iPadOS?

[stuartmorgan-g]

Sorry, I don't understand the question. What impact do you believe 10.15 has on the implementation of keyboard shortcuts in macOS menubars? I don't see any changes to the NSMenu or NSMenuItem APIs.

[rodydavis]

Sorry, I meant to say does this change anything you have done for the initial menubar plugin?

but you answered my question looks like it didn't.

[stuartmorgan-g]

I'm still not understanding. The APIs for setting menubar shortcuts have been the same since macOS 10.0, so I'm not clear on why you would expect 10.15 to change anything. What announcement or API change prompted this question?

[rodydavis]

@stuartmorgan just watching all the keynotes from WWDC19. I'll see if I can find the link but with SwiftUI it really focused on context menus and with them coming to MacOS it would create the correct navigation menus and submenus.

I don't think the API changed for NSMenu and MSMenuItem. But I do know they added context menus: https://developer.apple.com/documentation/swiftui/navigationview/3285966-contextmenu

[stuartmorgan-g]

Since there are no plans to use SwiftUI in the macOS Flutter embedding, how it wraps portions of AppKit will have no impact on plugins in this repository.