ios uiscrollview with pagingenabled between uiimageviews how to detect which one is on the screen/visible
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So I have a UIScrollview that scrolls horizontally with paging through a bunch of different UIImageViews containing user avatars. But, I want to only load the avatars from their URL IFF they are actually showing on the screen (4 are showing at a time, but I can scroll through like 30 or more or less). __Is there a way of detecting which UIImageView/ which page it is on? Or does anyone have any general recommendations or ideas for how I should go about this problem?__ Thank you in advance.