Declaring and checking/comparing (bitmask-)enums in Objective-C

Question

You know in Cocoa there is this thing, for example you can create a UIView and do:

view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIV         


        

Answer 1

While @Regexident has provided an excellent answer - I must mention the modern Objective-C way of declaring Enumerated options with NS_OPTIONS:

typedef NS_OPTIONS(NSUInteger, DownloadViewStatus) {
  FileNotDownloaded = 0,
  FileDownloading   = 1 << 0,
  FileDownloaded    = 1 << 1
};

Further Reference:

• NSHipster
• I Am The Walrus