All my views/pages in apps so far have been full screen UIViewControllers that i push and pop from the stack.
I see some apps create a new view/window that appears about the 1/3 the size of the full screen on an iPad, containing tables of items to select or other UI elements. They are commonly used to allow users to filter the current view they were on.
Seeing them in apps, I guess that they are just adding a UIView to there current screen and change its frame depending on where on the screen they want it to appear.
Or am I wrong? Is there another/better way to do this?
It’s a little unclear from your question what the view looks like.
If the view is “attached” to a UI element (has a little triangular arrow connecting it to, e.g., a button) and goes away if you tap outside it, then it’s a view presented from a UIPopoverController.
If the view overlays everything and dims the content behind it, is likely a model view controller presented with a presentation style of ether page sheet or form sheet.
Both are common and easy to set up. See the class documentation I have linked.