update widget design for Android 12

[hadrienbecle]

Hi :)

I've updated the widget to the new design guidelines (see https://developer.android.com/guide/topics/appwidgets). This includes:

• Border radius controlled by the OS on Android 12+ (which on my One UI device makes the widgets look more uniform)
• Widget preview instead of an image on Android 12+ (it looks more like the real widget, respects the device theming, and supports localization if it's added to trackworktime in the future)
• Use Material 3 DayNight theme (it's somewhat different from the rest of the app, but it looks much better on the home screen, and respects device theming and light/dark preferences)
• I'm not sure about the buttons border radius, I thought it was supposed to be entirely round with Material 3 (and it looks so on the preview in Android Studio), but they aren't on my device which can look weird when resizing at a very small size (might be related to One UI); I didn't want to overwrite default behaviour so left it as is
• I've also deleted the light grey border around the widget. I have no widget with such a border on my older devices; was that in older Android design guidelines?

Some screenshots:

Before/after on Android 8:

Before/after on Android 12 with light mode:

Before/after on Android 12 with dark mode:

Image preview of the widget (< Android 12):

Layout preview of the widget (Android 12):

[mathisdt]

Hi @hadrienbecle, thank you for your contribution! This looks really sleek. :sunglasses:

While testing I found out that on API level 21 (Android 5 is the minimum version for TWT) through 28 the widget background is white now, with no possibility to change it as the dark mode does not exist in the system yet. I think that the background should stay the same color for those old Android versions - could you please add that to the PR?

(BTW: The preview has the dark background, but the resulting widget does not.)

[hadrienbecle]

So, this is weird, but the DayNight theme works as expected on my Android 8 device (API level 26). I can choose a light or dark mode, and the widget respects that.

I suspect Galaxy Themes sort of sets a dark mode system variable that was only made generally available on Android 10+, but I wasn't able to find any info on that...

I've updated to use the Material 3 Dark theme on devices below API level 28. I can't switch anymore between light or dark on my Samsung device, but at least it defaults to dark mode on other older devices (tested with the Android emulator).

[mathisdt]

@hadrienbecle Thanks for your work! (And sorry that it took me so long to find the time for having a look at it.)