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POBest time in View lifecycle to determine the on-screen size of a UIScrollView
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copied!<p>I have a .xib containing a view which itself containing top and bottom accessory views (navigation, a page control) and a UIScrollView. Its height varies depending on whether I'm running on an iPhone 4 or 5 (3.5" or 4"). At runtime I move the containing view offscreen, populate the scrollview with UIButtons to build a scrollable launchpad, and scroll this on to the screen from the bottom. Tapping a button shows another view. </p> <p>On a smaller screen I'd like to show only three buttons in the scrollview, on the larger one I show four. So I need to know the height that the scrollview will be when it appears, before it actually appears. I'd hoped to have this information available at some point in the view lifecycle (viewWillAppear etc.) but the only place this seems to be correct is in viewDidAppear. At this point the view is already on screen and creating the buttons then means they appear suddenly, and are not scrolled nicely onscreen.</p> <p>The top-level view in the .xib is set to Retina 4 FullScreen.</p> <p>I'm happy to concede that viewWillAppear is the correct place to create the buttons and my navigation controller is perhaps instantiating the view incorrectly, but my iOS-fu isn't strong enough to say for certain.</p> <p>My solution has been to detect screen size and hardwire the button height. Is there a better (more elegant, future-proof and canonical) way to do this?</p>

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