o_extra.java

public class CustomEditText extends EditText {
    public CustomEditText(Context context) {
        super(context);

    }

    public CustomEditText(Context context, AttributeSet attrs) {
        super(context, attrs);
        Util.setCustomFont(this,context,attrs,
                R.styleable.CustomTextView,
                R.styleable.CustomTextView_font);
    }

    public CustomEditText(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        Util.setCustomFont(this,context,attrs,
                R.styleable.CustomTextView,
                R.styleable.CustomTextView_font);
    }

    public void setFont(String font) {
        Util.setCustomFont(this, getContext(), font);
    }
}