I have similar problem as the person who asked this question (TeXstudio, no preview pdf file after compiling using User Commands), which was not solved.
Since I use package minted to insert Python code in my document, I use this user command to compile my code:
xelatex -8bit -shell-escape -synctex=1 -interaction=nonstopmode %.tex | txs:///view-pdf
With this command, I generate the correct pdf file, but the problem is that the internal pdf viewer will not pop up.
How can I use user command and have internal pdfviewer at the same time?