How to debug slow app launch

Question

When launching my app i get the launch screen for about 2-3 seconds and only then my first UIViewController appears.

And some times my ViewDIdAppear is being called

Answer 1

In Xcode: Product -> Profile

Choose the "Time Profiler"

Running this tool will give you time spent in every method in your program, and it'll give you that information in a hierarchical structure. This should give you an idea where most of the time is spent. Keep in mind that the instrumentation adds extra overhead, so the absolute time value may not be correct, but the proportion of time spend in each method should what you need to debug this issue.

Here is a decent looking tutorial (albeit on an older version of Xcode) showing how to use this tool.