1.If the project on cloud is opened by another instance, then show Attention dialog, and not open this project again.
2.If the project on cloud is locked/checked out, then show Attention dialog for User to decide to open it as read-only or not.
if choose yes, then open as read-only.
if not, then try to unlocked/checked in this project, when unlocked/checked in successfully, then open it normally; otherwise, will also show message “This file can not be unlocked/checked in. It is opened as read-only.”, and open it as read-only.