[Android, 9.0 Preview 7] Blue notification / action bar started to appear on all modal pages

[janne-hmp]

Description

Compared to .NET MAUI 9.0 Preview 6, Preview 7 shows a blue notification / action bar on every modal page on Android, and it seems impossible to turn it off. MainPage does not have the blue bar, and it fades in when any other page (all modals) is opened. Does anybody know how disable the notification /action bar so that it does not appear on modal pages, similar to how it worked in Preview 6? (The blue bar used to be all black and empty in Preview 6.)

Steps to Reproduce

1. Build GnollHackM at https://github.com/hyvanmielenpelit/GnollHack using .NET 9.0 Preview 7 and start the app.
2. The first page (MainPage) does not have the blue notification bar.
3. Go to About page. When the page opens, also the blue notification bar fades in, unlike if you build the app in Preview 6

Link to public reproduction project repository

https://github.com/hyvanmielenpelit/GnollHack

Version with bug

Unknown/Other

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

Last version that worked well

Unknown/Other

Affected platforms

Android

Affected platform versions

Android 14

Did you find any workaround?

No.

Relevant log output

No response

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[jfversluis]

I see a lot of files in your project 😄 can you maybe be a bit more specific where in your code you are seeing this behavior?

[mattleibow]

Does this happen in the File | New template for you?

[jfversluis]

Can you change these values here: https://github.com/hyvanmielenpelit/GnollHack/blob/a198e58835dac23f6cb5e539919e09c39d8cc768/win/win32/xpl/GnollHackM/Platforms/Android/Resources/values/colors.xml#L4

And let us know if that influences the behavior?

I think this always worked this way, I wonder why this changed between preview 6 and 7?

[janne-hmp]

The notification bar used to be hidden, i.e., empty with just black. It is still like that on the game's MainPage, but then suddenly the bar fades in on all other pages (?). This may be related to Android SDK version 35 somehow.

[janne-hmp]

Yes, changing PrimaryDark to "#000000" (<color name="colorPrimaryDark">#000000</color>) did change the notification bar's background color to black, but obviously did not hide it. The notification bar fades in when a modal page scrolls in, and fades out when the modal page scrolls out. Note also that there is both the top bar and the bottom bar on modal pages, while on MainPage there's neither.

Currently, the system bars are hidden using the following Android functions in MainActivity, which seems to work on MainPage, but not on modal pages anymore. (Also, Xamarin Android works still just fine using the same code.)

        Window.AddFlags(WindowManagerFlags.Fullscreen);
...
            activity.Window.SetDecorFitsSystemWindows(false);
            activity.Window.InsetsController?.Hide(WindowInsets.Type.SystemBars());
            if (activity.Window.InsetsController != null)
                activity.Window.InsetsController.SystemBarsBehavior = (int)WindowInsetsControllerBehavior.ShowTransientBarsBySwipe;

There's a remark in Visual Studio that SetDecorFitsSystemWindows has been obsoleted in Android SDK version 35. That does not seem to explain though, why things work on MainPage, but not on modal pages.

[janne-hmp]

This may have something to do with the fact that App.Current.MainPage was deprecated and I had changed App.Current.MainPage.Navigation.PushModalAsync(page) to App.Current.Windows[0].Navigation.PushModalAsync(page). I now also tried just Navigation.PushModalAsync(page) (via ContentPage), but the result stays the same.

EDIT: In .NET 8.0: The default MAUI project seems to work just fine in this respect, but I have still no idea what my app does differently from the default app in showing modal pages. In GnollHack, I did override OnCreateWindow as per the Preview 7 instructions but setting App.MainPage instead of overridden window creation does not seem to help here.

EDIT: In .NET 9.0 Preview 7, the same blue bar appears in the default MAUI app on Android on a modal page, when you hide the bars as per the other comments.

[janne-hmp]

I can also confirm that this happens in the default MAUI app in 9.0 Preview 7 when you hide the bars as per above:

        Window.AddFlags(WindowManagerFlags.Fullscreen);
...
            activity.Window.SetDecorFitsSystemWindows(false);
            activity.Window.InsetsController?.Hide(WindowInsets.Type.SystemBars());
            if (activity.Window.InsetsController != null)
                activity.Window.InsetsController.SystemBarsBehavior = (int)WindowInsetsControllerBehavior.ShowTransientBarsBySwipe;

I tested earlier accidently 8.0, which worked fine.

The main page (no blue bar):

There's a modal page added to the click button (it is mostly all beige), and when it opens the page, the blue bar and the bottom navigation bar both fade in, also resulting in janky readjustment of the screen size:

If anybody knows any workarounds for this, let me know, or should I just wait for RC1?

[janne-hmp]

I can confirm this still happens in RC1.

[maonaoda]

Need a way to modify dialog.Window before model(dialog) is displayed eg：set BarColor to Transparent

            window.ClearFlags(WindowManagerFlags.TranslucentStatus);
            window.AddFlags(WindowManagerFlags.DrawsSystemBarBackgrounds);
            window.SetStatusBarColor(Android.Graphics.Color.Transparent);
            window.SetNavigationBarColor(Android.Graphics.Color.Transparent);

https://github.com/dotnet/maui/blob/3aea7836812b011b8c2b6f646e289d292519f5d3/src/Controls/src/Core/Platform/ModalNavigationManager/ModalNavigationManager.Android.cs#L250-L260