Modernize Activity Bar with NavigationView

[michael-hawker]

AI Dev Gallery has the modernized Store style Navigation which will work well for us (plus the Primary Side Bar - VS Code terms).

I think that's style is here: https://github.com/microsoft/ai-dev-gallery/blob/main/AIDevGallery/Styles/NavigationView.xaml

[michael-hawker]

I've been tackling #4 and #3 together as part of an overall revamp of the modernization of the app. Finally got something working again, though it's a bit rough. I think these are the remaining issues:

• Need to figure out how to re-enable collapsing with the new NavigationView Style
• Disabled style isn't distinguishable (when on welcome/settings page)
  • Could theoretically make these take-over pages on the left for the settings and a "new", that take over the whole tab area/content of the app... Maybe that's easier than trying to treat them as documents and simplifies that logic? (especially as we only let you open one at a time anyway...) Liking this more, then this maybe doesn't matter as much for now?
• Need to select NavigationViewItem on start?

[michael-hawker]

Looks now like with fixes to the templating to use MUX all the way down that the selection on start is working as expected. (wait, sometimes it doesn't work, is it a loading/timing issue?)

[michael-hawker]

New ActivityBar I think is mostly working, there's a weird issue with the Explorer selection on very first load. i.e. if you try and re-open the Explorer after closing it the first time, it won't re-open, seems like NavigationView is in some weird inconsistent state with the selection? Need to investigate, after clicking on another activity and going back and stuff it all works, just first time.

After Welcome/Settings refactor, will rev to 2.0 updating Welcome page, and will merge the modern-navigation branch!

[michael-hawker]

Using whole app frame for Welcome/Settings is working well, simplifies the document tracking and such, though complicates a bit of the side bar logic.

• Need to add a "LastOpenActivity" when switching to Welcome/Settings, so when you deselect and go away from them that the original sidebar you had open (if you did have one) stays open.
• Should probably have Esc key close settings/welcome page as well.
• Need to simplify FlipView style to remove the buttons and gestures (though maybe I should use a different container? The switch animation is nice though...) - May also be interfering with rendering or state or something...
• Need to fix the gap between TabView and the Document

Other things that need cleaning up now after:

• Tab selection color is hard to see
• The Side Bar Activities themselves need some revamping...

[michael-hawker]

The Settings/Welcome page as full pages is in the titlebar-rework branch, I just tested upgrade from a save state that had the welcome and settings tab open and it worked as expected. 🎉 Looking pretty slick now, but need to move away from the blue styles for the other panels. Look to use standard brushes from gallery:

[michael-hawker]

Revamped the explorer activity (side bar page) look and feel to be more inline with base WinUI styles, needs a bit of work on buttons still, but I think alright.

[michael-hawker]

Did some revamping of the other activities the other day, so we're close. Need to fix the issue with the FlipView really to have this usable...