Do virtual space apps in Android provide a fully virtual environment? There are virtual space apps for Android, such as Parallel Space or Dual Space. I know that we can't access outside files in a virtual environment, but I was able to access them in Dual Space's virtual environment.

Do such virtual space apps provide a fully virtual environment?
If virtual space apps are acting like Parallel Space then they are virtualizing the app runtime environment. Accessing external storage would not be a problem.

Commonsware put up a blogpost explaining what is going on under the hood with this virtualization with a caveat:


  However, this sort of virtualization technique – Android apps running inside other Android apps, for an Inception-style experience – requires that you trust the virtualization engine. After all, by definition, it can see all I/O between the app and Android, as it proxies all of that I/O. It is a [Man-In-The-Middle] MITM attack on the app.


So if you trust the makers of Parallel Space (or don't care) it is an option to consider.

From my answer: https://android.stackexchange.com/a/169048/3573