Fix system nav bar color

[micahmo]

Alright, I believe I've finally fixed the issue of the system nav bar color! See this comment and this comment for more context.

The clue came from this comment: rydmike/flex_color_scheme#178 (comment) Doing what they suggested fixed the issue!

Before

qemu-system-x86_64_4xXkaCSTqb.mp4

After

qemu-system-x86_64_q4p316Xmbn.mp4

Note that there is one subtle difference now. On pages that don't have the in-app nav area at the bottom, you can see that the system nav bar is completely transparent, whereas before it was white. (To be honest, I would've expected it to always be transparent, given what we were setting it to.) That said, I'm not sure if it's a big deal. It's probably all part of Google/Flutter's push to make apps truly edge-to-edge. For reference, Sync and Relay also both have a completely tranparent system nav bar. (I'm curious what Thunder looks like on iOS.) What do you think?

Before (white nav bar in comments)

qemu-system-x86_64_hsrGBkbRD9.mp4

After (transparent nav bar in comments)

qemu-system-x86_64_EdJVzTEyUd.mp4

---

Please review with whitespace off.

P.S. It's possible we don't need this code any more, but I left it anyway.

thunder/lib/main.dart

Lines 238 to 242 in 61c9392

	SystemChrome.setSystemUIOverlayStyle(
	SystemUiOverlayStyle(
	systemNavigationBarColor: Colors.black.withOpacity(0.0001),
	),
	);

[hjiangsu]

Wow, great find! I took a look at the links you mentioned, and also found a possible suggestion/improvement (up to you whether you want to implement it though!) flex_color_scheme exposes a static function that allows us to customize the system navigation bar a bit further: FlexColorScheme.themedSystemNavigationBar.

Thoughts on switching to this rather than specifying our own SystemUiOverlayStyle as its probably more robust?

For example:

SystemUiOverlayStyle systemUiOverlayStyle = FlexColorScheme.themedSystemNavigationBar(context, systemNavBarStyle: FlexSystemNavBarStyle.transparent);

AnnotatedRegion<SystemUiOverlayStyle>(
    value: systemUiOverlayStyle,
    child: ...
)

[micahmo]

I'm good with doing that! My only concern is that it only allows us to set the value of navigation bar. I'm also working on fixing the color of the status bar, and I might have to do it in the same area, which means specify a custom SystemUiOverlayStyle. But I'll cross that bridge when I come to it. I just pushed your suggested change, and I went ahead and removed the old code that probably isn't needed. Should be good to go, if it looks good to you!

[hjiangsu]

LGTM! Thanks again for finding this fix!