What's difference between NSPhotoLibraryAddUsageDescription and NSPhotoLibraryUsageDescription?

Question

My app get crashed today while updating on Xcode9, testing on iOS11. After adding NSPhotoLibraryAddUsageDescription then it works, even i already had NSPh

Answer 1

You gonna need both.
Because once I tried use UIActivityViewController to save image to library, my iphone version is 11.3, I only use NSPhotoLibraryUsageDescription and it's crash because i need NSPhotoLibraryAddUsageDescription.
But ios 9.3 not crash.