Xcode keeps building storyboard after each keystroke
My Xcode project using a storyboard entered in a very weird state recently: Xcode keeps building the whole project and notably the storyboard after each keypress. I found no reason for this behavior neither in my project diffing all interesting files (storyboard and project) neither a setting in Xcode (maybe I just could not find it?) Needless to say that this "feature" makes working on my project nearly impossible since the CPU is constantly occupying with rebuilding the storyboard when I type new code. Anybody seen this?
Answer
It is caused by the IB_DESIGNABLE definitions in the source header files. Probably it makes problem only if the header file containing IB_DESIGNABLE is included (even implicitly) to the source file you are currently editing.
I did not find a definitive solution how to disable IB_DESIGNABLE and thus compiling the storyboard and the source files continuously. I would appreciate an Xcode flag to disable this temporarily. I tried also surrounding the IB_DESIGNABLE with #ifdef macros but they are considered even if the #ifdef evaluates to false. Commenting out one by one the IB_DESIGNABLE helps but it is not a feasible solution with many IB_DESIGNABLEs.
Update
I finally found a quick way to avoid this annoying behavior. Having the storyboard opened in the active window, disable "Automatically Refresh Views" from the Editor menu. This will stop updating the views in the storyboard editor that use your custom code and thus speed up your development significantly. When you need again the just-in-time compiling to have a visual preview of your custom code, enable this option again (it seems you also have to re-open your storyboard to make it working again).
You may wish to add a key binding to the command, such as command-option-control-A, to easily toggle the behavior on/off. To add a key binding in Xcode, touch command-comma for preferences, choose the Key Bindings tab, use the search bar to find the command, then double-click on the right area to add your desired keystroke.
"Leave it off" approach
Alternately turn "Automatically Refresh Views" off, and never turn it on.
Make a convenient keystroke for "Refresh all views", say command-option-shift-R
As you work, just touch command-option-shift-R from time to time, or as needed. It's generally only necessary to touch command-option-shift-R as you work on the storyboard.