Hi, I have a question regarding using color resour...

# glance

[Jan Bína]

Hi, I have a question regarding using color resources in glance.
In some cases, it is not possible (or I haven't found a way) to use a color resource - for example to set the color of Text, because color of TextStyle is of type ColorProvider and the factory function to create ColorProvider from resource is restricted to the library and says

Returns a [ColorProvider] that resolves to the color resource. This should not be used outside of the Glance Libraries due to inconsistencies with regards to what process (app vs launcher) colors are resolved in

That's also the case with colorFilter for Image , color of CircularProgressIndicator and probably more.
On the other hand, there's a .background modifier that accepts color resource and is working just fine.
I tried to overcome this by using RemoteViews directly, so for example I can set the color of Text like this:

AndroidRemoteViews(
    remoteViews = RemoteViews(context.packageName, R.layout.widget_textview).apply {
        setTextViewText(R.id.text, text)
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
            setTextViewTextColorResource(R.id.text, colorRes)
        } else {
            setTextColor(R.id.text, LocalContext.current.getColor(colorRes))
        }
    },
)

and this seems to be working fine too. After all, the glance theme's dynamic colors are also created from resources...
So, what's the reason for that restriction of ColorProvider ? And can my approach with remote views cause troubles in some cases (not resolving to correct color)?

[bbade_]

Sorry in the delay getting back to you.

The issue we've seen is that it's easy to make mistakes when dealing directly with color resources in glance. The reason is that there's a couple of things that can change.
• Light/Dark theme
• Dynamic colors.
In particular, if there's scenarios where some colors get resolved in the appwidget's process, but other colors get resolved in the launcher, there can be discrepancies.

In the example you gave, setTextColor(R.id.text, LocalContext.current.getColor(colorRes)) runs the risk of not updating if the appwidget's host (launcher most likely) switches from light to dark mode. Anything that is using GlanceTheme or resources in the remoteviews will update, but anything that's hardcoded wont.

There's a couple guidelines for using color.
• Create a GlanceTheme
• Don't use resource defined colors, either use dynamic color, or hard code light and dark color values for each of your tokens in the app and give them to a `ColorProvider(day=..., night=...)
You can see some examples of working with color in our demos directory, and in particular, the demos subproject

https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:glance/g[…]on-tests/demos/src/main/java/androidx/glance/appwidget/demos/

[Weronika Nowak]

Is there a way to implement GlanceTheme with light and dark modes on Android SDK <= 30 or should I use RemoteViews?