Assigning the placeholderItem property in the UIActivityItemProvider class

Question

What is the purpose of the placeholderItem property in the UIActivityItemProvider class?

All documentation states are as follows:

An object that can stand for the real object that you plan to create. The contents of the object may be empty, but the class of the object must match the class of the object that you plan to provide later.

I am wondering how this property is actually used internally. Is it displayed at any time in the user interface?

Answer 1

From the UIActivityItemProvider.h header

placeHolder is the return value for -activityViewControllerPlaceholderItem:

-activityViewControllerPlaceholderItem: - UIActivityItemSource, UIActivityItemProvider.

:

. . , -itemActivityType:

, Apple , placeholderItem.