What is the purpose of offScreenView?

[liuxuan30]

I have read the code, and I am loosing the understanding of the reason for offScreenView. what I saw is updating a view's frame, but why not direclty utilize greenView's frame?

[smileyborg]

Hey Xuan,

Did you watch the Adaptive Auto Layout talk that this code was part of? If not, you'll want to watch that, or at least the part that covers this Offscreen Layout technique (here's the relevant portion).

Let me know if you still have any questions.

[liuxuan30]

Sorry I did, but the volume is not very loud so I don't get much information.

[smileyborg]

What is your question then? I'm not sure I understand what you are asking.

[liuxuan30]

I am not sure why to use offScreen views, as the talk video not explained it well, kind of noisy and not very clear what you said

[smileyborg]

This is an advanced technique that lets you use Auto Layout to do things that are traditionally impossible to do. Offscreen views are used to perform a number of layout calculations quickly, and then store the outputs of those calculations (view frames) for later use.

If you are just getting started with Auto Layout, this is not something you should or need to worry about.

[liuxuan30]

Thanks, I having been using Auto layout for a while, and I want to go to the next level. Could you give some links or docs that explains this advanced technique?

[smileyborg]

Sorry, I don't have any documentation or links beyond the video of this talk and the slides. If I get some time to write up a description I will include it in the README of this project.

[liuxuan30]

Alright, looking forward your README :)