set font to root view.

TypefaceUtil.java

public class TypefaceUtil {

  public static void setTextTypefaceNormal(View view, Typeface typeface) {

        if (view instanceof ViewGroup) {

            ViewGroup viewGroup = (ViewGroup) view;
            int childSize = viewGroup.getChildCount();
            for (int idx = 0; idx < childSize; ++idx) {
                TypefaceUtil.setTextTypefaceNormal(viewGroup.getChildAt(idx), typeface);
            }
        }

        if (view instanceof TextView) {
            TextView textView = (TextView) view;
            if (textView.getTypeface() != typeface) {
              textView.setTypeface(typeface);  
            }
            
        }
    }
}