Fix Android text alignment in migrated projects

[jknaudt21]

Problem

Android projects that either used an API level below 17 or have android:supportsRtl="false" (or not included) in the app manifest would not properly align text. This particularly impacted migrated projects, since their manifests didn't supportsRtl.

The issue stemmed from the fact that in cases where Rtl was not suppported, we relied on a TextView's Gravity flags. We ended up overwriting the horizontal alignment settings when updating vertical alignment.

Solution

When updating vertical or horizontal alignment settings, the following logic is followed:

1. Create a mask for the bits pertaining to the setting we want to change.
2. Get the complement of said mask and do a bitwise AND with the current settings. This ensures that we only clean the Gravity bits for the setting we want to modify
3. Do a bitwise OR with the new settings and any additional setting we want to pass

Before	After

Issues Fixed

Fixes #11251

Tests added

I added a couple of Device tests to SearchBar, Editor, Entry, and Label to test that this works. The only drawback is that these tests will only run if the Android Manifest of the Controls.DeviceTests project is manually edited to have android:supportsRtl="false". This seemed to be the most efficient solution without requiring high amounts of engineering effort considering that this is a fairly niche case that primarily occurs on migrating projects.

Note: These screenshots are displaying slightly outdated display names for the tests. They are all consistent now (similar to the label screenshots)

Work remaining

• Write test

[mattleibow]

Do you have a link to an issue to create the manual test for future us?

[mattleibow]

Looks great, maybe a small change to reduce some duplicated code and semi-future-proof the tests.

[hartez]

Question about the masks.

[jknaudt21]

@mattleibow added the manual test issue: #17014

[mattleibow]

Suggested change

	{
	view.Gravity = (view.Gravity & ~HorizontalGravityMask) | alignment.ToHorizontalGravityFlags() | orMask;
	}
	view.Gravity = (view.Gravity & ~HorizontalGravityMask) | alignment.ToHorizontalGravityFlags() | orMask;

[primozcerar]

This needs to be ported to net7. Currently you can't set both HorizontalTextAlignment and VerticalTextAlignment on a Label. Only the last one set is respected and the first one is then ignored, so for example Center, Center is not possible and you have to add another layout around the Label to achieve that. This is a core functionality that just wasted an hour of my time and it the bug is a regression that was introduced in the last half year or so since it only appeared after I updated Visual Studio and with it the MAUI version.