Is there a better formatting option for an alternated enumerated/itemized list?

Question

I'm making a questions/answers page where answer follows the question. The questions are enumerated while the answers are not. Questions are using one color while answers using another one.

In order to pause numeration, I've used the solution provided to this question. As a result, my code looks like this in general:

\documentclass[english]{article}
...
\newcounter{savedenum}
\newcommand*{\saveenum}{\setcounter{savedenum}{\theenumi}}
\newcommand*{\resume}{\setcounter{enumi}{\thesavedenum}}
...
\usepackage{parskip}
\usepackage{color}
\usepackage[usenames,dvipsnames,svgnames,table]{xcolor}
\usepackage{enumitem}
...
\begin{document}
...
  \begin{enumerate}
    \item \color{black}{Question text goes here.}
    \saveenum
  \end{enumerate}

  \begin{itemize}
    \item[] \color{NavyBlue}{Answer text goes here.}
  \end{itemize}

  \begin{enumerate}
    \resume
    \item \color{black}{Question text goes here.}
    \saveenum
  \end{enumerate}

  \begin{itemize}
    \item[] \color{NavyBlue}{Answer text goes here.}
  \end{itemize}
...
\end{document}

Since there is a lot of code reuse, I'm seeking for a better solution (maybe a loop of some kind?), if possible, that will substitute the copy-and-paste of the \begin{...} ... \end{...} blocks.

Answer 1

I suggest a different approach:

\documentclass{article}
\usepackage[usenames,dvipsnames,svgnames,table]{xcolor}

\newif\ifsolutions
\solutionstrue
\newenvironment{exercises}
 {\begin{enumerate}}
 {\end{enumerate}}
\newenvironment{question}
 {\item}
 {}
\ifsolutions
  \newenvironment{solution}
   {\par\nopagebreak\begingroup\color{NavyBlue}}
   {\endgroup}
\else
  \usepackage{comment}
  \excludecomment{solution}
\fi

\begin{document}
\begin{exercises}

\begin{question}
Question one text goes here.
\end{question}
\begin{solution}
Answer one text goes here.
\end{solution}

\begin{question}
Question two text goes here.
\end{question}
\begin{solution}
Answer two text goes here.
\end{solution}

\end{exercises}

\end{document}

The markup might seem excessive, but it allows for greater flexibility: you can customize exercises using enumitem features, but also question and solution. I've added a possibility: if you comment the

\solutionstrue

line, the solutions will not be printed at all.

Solutions active

Solutions suppressed

Answer 2

Since you're already loading the enumitem package, here's a solution using the resume feature:

\documentclass{article}
\usepackage{enumitem}
\usepackage{parskip}
\usepackage[usenames,dvipsnames,svgnames,table]{xcolor}

\newenvironment{question}{\enumerate[resume]\item}{\endenumerate}
\newenvironment{solution}{\itemize\item[]\begingroup\color{NavyBlue}}{\endgroup\enditemize}

\begin{document}

  \begin{question}
    Question text goes here.
  \end{question}
  \begin{solution}
    Answer text goes here.
  \end{solution}
  \begin{question}
    Question text goes here.
  \end{question}
  \begin{solution}
    Answer text goes here.
  \end{solution}
\end{document}

If you'd prefer to have your own list (perhaps you're using the enumerate environment outside of this task) then you could use a newlist

\newlist{myenumerate}{enumerate}{5}
\setlist[myenumerate]{label=\arabic*.,resume}

\newenvironment{question}{\myenumerate\item}{\endmyenumerate}

Finally, if you'd like to suppress the solution environment, or perhaps output it to a separate file, I'd recommend looking at the answers package; you can switch the answers on and off in the main part of the document by using

% solutions written to file (NOT to main part of document)
\usepackage{answers}   
% solutions NOT written to file (written to main part of document)
\usepackage[nosolutionfiles]{answers}

Complete MWE

\documentclass{article}
\usepackage{enumitem}
\usepackage{parskip}
\usepackage[usenames,dvipsnames,svgnames,table]{xcolor}
\usepackage{answers}
%\usepackage[nosolutionfiles]{answers}

\newlist{myenumerate}{enumerate}{5}
\setlist[myenumerate]{label=\arabic*.,resume}

\newenvironment{question}{\myenumerate\item}{\endmyenumerate}

% open the answer file
\Opensolutionfile{shortsolutions}
\Newassociation{solution}{ShortSoln}{shortsolutions}

\begin{document}

\begin{question}
    Question text goes here.
    \begin{solution}
        Answer text goes here.
    \end{solution}
\end{question}
\begin{question}
    Question text goes here.
    \begin{solution}
        Answer text goes here.
    \end{solution}
\end{question}

% close the solutions files
\Closesolutionfile{shortsolutions}

\clearpage

% this just makes the displayed solutions use the itemize
% environment- makes the dispaly better
\renewenvironment{ShortSoln}[1]{%
\itemize\item[{\bfseries(#1)}]%
}%
{\enditemize}

% input the answers file
\section*{Answers}
\IfFileExists{shortsolutions.tex}{\input{shortsolutions.tex}}{}
\end{document}