Import custom fonts to Android Studio for use in Layouts?

You can programmatically use fonts in your assets directory, you must create an object of type Typeface from a source file.

You place your source file in the assets folder, you can place a subfolder inside that is called fonts if you want to take more order and instances a Typeface object so

//Definicion de clase de utilidades Fuentes.java por ejemplo

public static Typeface myFont(Context context) {
    return Typeface.createFromAsset(context.getAssets(), "fonts/Roboto-Light.ttf");
}

Then you apply your source to the component you want

TextView tv = findViewById ....
tv.setTypeface(Fuentes.myFont(this));

The tedious thing about this is if you want to apply the font to many components in your app.

To apply directly to Layout , as far as I know android-typeface-textview works only for TextView , plus it is deprecated

You can try Calligraphy as suggested, I have not tried it; but for your demo I see that it can be used directly to Layout by means of an attribute fontPath and in TextViews , styles and Buttons , try it and tell us.

Some examples that I provide are the following:

<EditText
    android:id="@+id/edit_text"
    fontPath="fonts/Roboto-Bold.ttf"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginBottom="16dp"
    android:layout_marginTop="16dp"
    android:hint="@string/edit_text_hint"/>

<CheckBox
    fontPath="fonts/Oswald-Stencbab.ttf"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginBottom="16dp"
    android:layout_marginTop="16dp"
    android:text="@string/checkbox_custom"/>

<Button
    android:id="@+id/button_bold"
    fontPath="fonts/Roboto-Bold.ttf"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:layout_marginTop="12dp"
    android:text="@string/button_defined"/>

<TextView
    fontPath="fonts/Roboto-None.ttf"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/defined_incorrect"/>

Googling a bit ....

There is a library that you can use as you mention, here is :

This would be the custom TextView you would use in this way:

<com.mobsandgeeks.ui.TypefaceTextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="stackoverflow en español"
geekui:customTypeface="fonts/custom_font.ttf" />