Using the Fonts in XML feature you can specify various font weights for a font family. For example:
<?xml version="1.0" encoding="utf-8"?>
<font-family xmlns:android="http://schemas.android.com/apk/res/android"
             xmlns:app="http://schemas.android.com/apk/res-auto">
    <font android:font="@font/archivo_narrow_regular" android:fontWeight="400" android:fontStyle="normal"
        app:font="@font/archivo_narrow_regular" app:fontWeight="400" app:fontStyle="normal"/>
    <font android:font="@font/archivo_narrow_regular_italic" android:fontWeight="400" android:fontStyle="italic"
        app:font="@font/archivo_narrow_regular_italic" app:fontWeight="400" app:fontStyle="italic"/>
    <font android:font="@font/archivo_narrow_medium" android:fontWeight="500" android:fontStyle="normal"
        app:font="@font/archivo_narrow_medium" app:fontWeight="500" app:fontStyle="normal"/>
    <font android:font="@font/archivo_narrow_medium_italic" android:fontWeight="500" android:fontStyle="italic"
        app:font="@font/archivo_narrow_medium_italic" app:fontWeight="500" app:fontStyle="italic"/>
    <font android:font="@font/archivo_narrow_semibold" android:fontWeight="600" android:fontStyle="normal"
        app:font="@font/archivo_narrow_semibold" app:fontWeight="600" app:fontStyle="normal"/>
    <font android:font="@font/archivo_narrow_semibold_italic" android:fontWeight="600" android:fontStyle="italic"
        app:font="@font/archivo_narrow_semibold_italic" app:fontWeight="600" app:fontStyle="italic"/>
    <font android:font="@font/archivo_narrow_bold" android:fontWeight="700" android:fontStyle="normal"
        app:font="@font/archivo_narrow_bold" app:fontWeight="700" app:fontStyle="normal"/>
    <font android:font="@font/archivo_narrow_bold_italic" android:fontWeight="700" android:fontStyle="italic"
        app:font="@font/archivo_narrow_bold_italic" app:fontWeight="700" app:fontStyle="italic"/>
</font-family>
But I cannot figure out how to actually make use of each of these weights; either in an XML (layout/style) file, or in Java code. Their is no fontWeight attribute available for TextView, and the Typeface object created from ResourcesCompat.getFont(context, R.font.archivo_narrow) has no mention of font weights.
I realize that I can just specify the specific font resource (i.e. R.font.archivo_narrow_semibold), but then what is the point of having a fontWeight attribute in the font-family?
Update
A new static create(Typeface family, int weight, boolean italic) method was added in API Level 28, along with a getWeight() instance method. This finally makes it possible to make use of the fontWeight attribute in Java code; though only for API Level 28 and above, I haven't found any analogs in the support library.
This is useful—and shows that the fontWeight attribute didn't serve any purpose in the past—but I would really like to be able to use the weight in XML styling.
 
     
    
 
     
     
     
     
     
     
     
     
     
    