iOS Make sure documents are open before accessing

Question

When opening UIDocuments from a closed state, I understand that it is it done on another thread. My question is, if I have code on my main thread that will access the document (

Answer 1

You should use documentState property of UIDocument class. For more detail refer this document documentState description.

It returns following enumerators to check:

enum {
    UIDocumentStateNormal          = 0,
    UIDocumentStateClosed          = 1 << 0,
    UIDocumentStateInConflict      = 1 << 1,
    UIDocumentStateSavingError     = 1 << 2,
    UIDocumentStateEditingDisabled = 1 << 3   }; typedef NSInteger UIDocumentState;

From Description: UIDocumentStateNormal is what you want, as:
The document is open, editing is enabled, and there are no conflicts or errors associated with it.