[NET6][Android] VisibleBoundsPadding and it's API are Not Working

[Soap-141]

Current behavior

Using Uno.UI.Toolkit.VisibleBoundsPadding.PaddingMask=Bottom with <item name="android:windowTranslucentNavigation">true</item> doesn't work and the Android navigation bar height is ignored.

Also this wasn't an issue on Xamarin with or without the windowTranslucentNavigation.

I also noticed that on Android 10, ApplicationView.GetForCurrentView().VisibleBounds.Bottom doesn't include the navigation bar height in it and can cause issues with custom controls even if it looks like it work inside Uno.UI.Toolkit.VisibleBoundsPadding.PaddingMask=Bottom. On some applications we need to set <item name="android:windowTranslucentNavigation">true</item> but not in the sample.

Android 13 issue:

Android 10 issue:

Expected behavior

How to reproduce it (as minimally and precisely as possible)

1. Download UnoAppTest.zip.
2. For Android 13 issue you can play around with <item name="android:windowTranslucentNavigation"></item> in Styles.xml.
3. For Android 10 issue, you can use breakpoints in MainPage.xaml.cs to see the actual values.
4. Doable on physical device and emulators.

Workaround

Android 13 issue:
Playing around with <item name="android:windowTranslucentNavigation">false</item> or <item name="android:windowTranslucentNavigation">true</item> may fix the issue.

Android 10 issue:
Adding some Android 10 specific code could fix the issue but it doesn't look like the right thing to do considering that it assumes that we must have bottom padding here.

private double GetBottomPadding()
{
#if __MOBILE__
	var bounds = App.MainWindow.Bounds;
	var visibleBounds = ApplicationView.GetForCurrentView().VisibleBounds;
	var bottomPadding = bounds.Bottom - visibleBounds.Bottom;

#if __ANDROID_10__
	// Workaround for Android 10, the navigation bar is not included in the visible bounds, so we need to add it manually.
	if (bottomPadding == 0)
	{
		var navigationBarHeightId = Android.Content.Res.Resources.System.GetIdentifier("navigation_bar_height", "dimen", "android");
		var navigationBarHeight = Android.Content.Res.Resources.System.GetDimensionPixelSize(navigationBarHeightId) / Android.Content.Res.Resources.System.DisplayMetrics.Density;

		bottomPadding += navigationBarHeight;
	}
#endif

	return bottomPadding;
#else
	return 0;
#endif
}

Works on UWP/WinUI

None

Environment

Uno.UI / Uno.UI.WebAssembly / Uno.UI.Skia, Uno.WinUI / Uno.WinUI.WebAssembly / Uno.WinUI.Skia

NuGet package version(s)

4.9.0-dev.580

Affected platforms

Android

IDE

Visual Studio 2022

IDE version

17.5.4

Relevant plugins

No response

Anything else we need to know?

No response

[Soap-141]

May be similar to #6218

[kazo0]

@carldebilly

Looks to be some sort of layouting/measuring issue on Android. Attached a small repro app - VisibleBoundsPaddingTest.zip. Some sort of race condition maybe? It seems that the VisibleBoundsPadding is properly setting the Padding on the control but it is not reflected in the UI until a re-layout is forced.

In the repro app, either you can:

• click the button to force a re-layout which causes the bottom padding to appear, or
• rotate the device, or
• uncomment the await Task.Delay(1000) in the code-behind and this causes the UI to reflect the Padding properly

Expected positions of green boxes:

Actual positions of green boxes:

Here's what happens when you click on the re-layout button, notice the bottom padding appears after clicking.

Also, @Soap-141, I get the same issue on a Xamarin/UWP app so I'm not sure if it's net6.0-android specific: sample app - VBPXamUWP.zip

[Soap-141]

@kazo0 Yeah I did not notice any issue on our Xamarin applications as of now but it could also be an issue I guess. As long as we can find a fix. Poke me if you need anything.

[Soap-141]

@kazo0 @jeromelaban I guess I should create a backport request for 4.8 after testing?

[Soap-141]

@kazo0 Should it be on 4.9.0-dev.1168?

[jeromelaban]

I'm not sure if we'll be able to backport to 4.8, this is quite a large change.

[jeromelaban]

@kazo0 Should it be on 4.9.0-dev.1168?

You can find published builds from this list.

[Soap-141]

The build is not ready yet. Will have to test later then.

[Soap-141]

@kazo0 @jeromelaban I tested Uno 4.9.0-dev.1195 and I still need to use a workaround on Android 10 when using a translucent navigation bar (See description to know how I do that).

// Workaround for Android 10, the navigation bar is not included in the visible bounds, so we need to add it manually.
if (safeAreaBottomPadding == 0)
{
	var navigationBarHeightId = Android.Content.Res.Resources.System.GetIdentifier("navigation_bar_height", "dimen", "android");
	var navigationBarHeight = Android.Content.Res.Resources.System.GetDimensionPixelSize(navigationBarHeightId) / Android.Content.Res.Resources.System.DisplayMetrics.Density;

	safeAreaBottomPadding += navigationBarHeight;
}

[kazo0]

@Soap-141 sorry the PR was accidentally merged and auto-closed the issue, im still working on it now. It should definitely have fixed the issue you are talking about though for Android 10- so this is concerning. I will look into it

[kazo0]

@Soap-141

I took your original sample app and removed the workarounds and updated it to my local uno nuget override with the changes and it looks to be working fine. It should look like this right?

Once the CI for the PR runs I will test with the packages it creates but I didn't really change anything since you tested so I'm not sure why it wasn't working for you. This is on an emulator running API 28

[kazo0]

Artifacts to test are here: https://dev.azure.com/uno-platform/_apis/resources/Containers/20142603/NugetPackages?itemPath=NugetPackages%2Fvslatest&%24format=zip&saveAbsolutePath=false

[kazo0]

Looks to be working, let me know if it works for you as well:

[Soap-141]

@kazo0 It's supposed to be API 29. But I'm testing again in a couple of minutes.

[Soap-141]

@kazo0 If I set toolkit:VisibleBoundsPadding.PaddingMask="Bottom" in XAML, it's working but the part in the screenshot doesn't work (it's always 0).

It's problematic because in some applications we are using custom behaviors that use those API.

[kazo0]

@Soap-141

I'm not quite sure I'm understanding the issue, you should just be able to use the bottomPadding in all your cases. There should no longer be a need to use VisibleBoundsPadding.WindowPadding.Bottom or the #if __ANDROID_10__ block

[kazo0]

Oh wait, are you saying bottomPadding is always 0??

[Soap-141]

@kazo0 Exactly, for Android 10.

[kazo0]

@Soap-141

Strange, it's working for me, I created a button and on click I grab the bottomPadding like you do and I am getting a value. Are you perhaps trying to calculate this too early? What is the value of the VisibleBounds when you debug?

[Soap-141]

@kazo0
Are you on Android 10 API 29 (I am using an emulator)?

[kazo0]

Strange, I am using an API 29 emulator:

@Soap-141, what nuget package version are you on? the ones from the pull request i linked?

[Soap-141]

@kazo0 Didn't have access to your link, so I assumed latest preview.

[kazo0]

ah i see, ok so this should all be fixed by #12444

[kazo0]

@Soap-141 you should be able to test with 4.10.0-dev.76

[Soap-141]

@kazo0 Thanks I'll be testing that out and may request a back port on 4.8/4.9 depending on what is possible.

[Soap-141]

It's working thanks @kazo0! https://github.com/unoplatform/nventive-private/issues/486