Parallax view scrolling (Yahoo weather like)

ios graphics parallax
Majster picture Majster · Jul 31, 2013 · Viewed 7.5k times · Source

This is not strictly a programming question but more "how to accomplish this" question.

I am curious (and working on an app that will probably require this) how is left-right parallax scrolling implemented. To know exactly what I mean check the Yahoo Weather app (it's free - no worries there).

Are they using just one view controller or a separate controller for each view that is shown there?
What is the easiest way to implement this? I have found this topic here which kinda explains it a bit but when are they getting information from their servers? Is it when the views are changed or at the startup of the app?

Any information how to implement such scrolling would be much appreciated.

Answer

Leonard Pauli picture Leonard Pauli · Jul 31, 2013

It's really simple actually:

  • Subclass UIScrollView
  • Add a UIView *parallaxView; as @property
  • Add a CGFloat parallaxFactor as @property
  • Override layoutSubviews
  • Call super, and then use self.scrollOffset*parallaxFactor to position the parallaxView

That's it!

I've made a multifunctional UIScrollView subclass myself that's really simple to use, perfect for this case! Get it on GitHub: https://github.com/LeonardPauli/LPParallaxScrollView

Good Luck!

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