Please follow basic customization of FontTextView, FontEditView, FontRadioButton, FontCheckBox and FontButton.
[ For the exact answer, after seeing this guide, please see:
https://stackoverflow.com/a/51113022/787399   ]
Use custom FontTextView, in ArrayAdapter item layout, like this:
public class FontEditText extends AppCompatEditText {
//    private String FONT = "fonts/roboto_regular.ttf";
    public FontEditText(Context context) {
        super(context, null);
//        setFontFromAsset(context, null, R.style.DefaultFontTextView);
//        FONT = getContext().getString(R.string.font_roboto_regular);
    }
    public FontEditText(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        setFontFromAsset(context, attrs, R.attr.fetFontStyle);
    }
    public FontEditText(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        setFontFromAsset(context, attrs, defStyleAttr);
    }
    private void setFontFromAsset(Context context, AttributeSet attrs, int defStyle) {
        BaseActivity activity = (BaseActivity)((MyApplication) context.getApplicationContext()).getCurrentActivity();
        FontAndLocaleManager fontAndLocaleManager = activity.getFontAndLocaleManager();
        fontAndLocaleManager.setFontFromAsset(this, R.styleable.FontEditText, R.styleable.FontEditText_fetFontFace, attrs, defStyle);
    }
}
use the code:
public void setFontFromAsset(View view, int[] resViewStyleable, int resStyleableViewFontFace, AttributeSet attrs, int defStyle) {
        String strFont = null;
        Typeface tfFontFace = null;
        String strButton = FontButton.class.getCanonicalName(),
                strTextView = FontTextView.class.getCanonicalName(),
                strEditText = FontEditText.class.getCanonicalName(),
                strView = view.getClass().getCanonicalName();
        try {
            if (view.isInEditMode()) {
                return;
            }
            //R.string.font_roboto_regular
            strFont = context.getString(R.string.font_roboto_regular);
            tfFontFace = Typeface.createFromAsset(context.getAssets(), strFont);
            //AttributeSet set, int[] attrs, int defStyleAttr, int defStyleRes
            //R.styleable.FontButton
            TypedArray a = context.obtainStyledAttributes(attrs, resViewStyleable, defStyle, 0);
            //R.styleable.FontButton_btFontFace
            String derivedFont = a.getString(resStyleableViewFontFace);
            a.recycle();
            //==
            try {
                if (derivedFont != null) {
                    Typeface derivedFontFace = Typeface.createFromAsset(context.getAssets(), derivedFont);
                    if (strView.equals(strButton)) {
                        ((FontButton) view).setTypeface(derivedFontFace);
                    } else if (strView.equals(strTextView)) {
                        ((FontTextView) view).setTypeface(derivedFontFace);
                    } else if (strView.equals(strEditText)) {
                        ((FontEditText) view).setTypeface(derivedFontFace);
                    }
                    return;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        try {
            if (strFont != null && tfFontFace != null) {
                if (strView.equals(strButton)) {
                    ((FontButton) view).setTypeface(tfFontFace);
                } else if (strView.equals(strTextView)) {
                    ((FontTextView) view).setTypeface(tfFontFace);
                } else if (strView.equals(strEditText)) {
                    ((FontEditText) view).setTypeface(tfFontFace);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
Describe style and attributes in respective xmls:
<!--FontTextView-->
    <declare-styleable name="FontTextViewStyle">
        <!-- Style of the FontTextView. -->
        <attr name="ftvFontStyle" format="reference"/>
    </declare-styleable>
    <declare-styleable name="FontTextView">
        <!-- Font face of FontTextView. -->
        <attr name="ftvFontFace" format="reference"/>
    </declare-styleable>
and
<!--FontTextView-->
<style name="StyledFontTextView" parent="@android:style/Theme.Light">
<item name="ftvFontStyle">@style/DefaultFontTextView</item>
</style>
<style name="DefaultFontTextView">
<item name="ftvFontFace">@string/font_roboto_regular</item>
</style>
define some more styles:
<style name="App_TextViewStyle" parent="@android:style/Widget.TextView">
        <item name="android:textColor">@color/text_grey</item>
        <item name="android:textSize">@dimen/sp_20</item>
        <item name="android:layout_width">match_parent</item>
        <item name="android:layout_height">wrap_content</item>
    </style>
    <style name="App_TextViewStyleMedium" parent="@android:style/Widget.TextView">
        <item name="android:textColor">@color/text_hint</item>
        <item name="android:textSize">@dimen/sp_18</item>
        <item name="android:layout_width">match_parent</item>
        <item name="android:layout_height">wrap_content</item>
    </style>
    <style name="App_TextViewStyleSmall" parent="@android:style/Widget.TextView">
        <item name="android:textColor">@color/text_grey_light</item>
        <item name="android:textSize">@dimen/sp_14</item>
        <item name="android:layout_width">match_parent</item>
        <item name="android:layout_height">wrap_content</item>
    </style>
mention fonts in your strings.xml:
...
<string name="font_roboto_regular">fonts/roboto_regular.ttf</string>
...
and use in the layouts saving some code and time:
<com.mypackage.custom_views.FontTextView
                style="@style/App_TextViewStyleMedium"
                android:layout_gravity="start|bottom"
                android:gravity="start|bottom"
                app:fetFontFace="@string/font_roboto_regular"
                android:text="@string/are_you_a" />
At Android level 16 and above, all this is simplified, because now you can keep TTF and other font resources in /res/font folder, rather than in assets. That removes most of the custom classes, styles and attributes, see:
Font Resources in Android
Happy Coding with style!! :-)