iOS Development--a summary of the new features of the grammar OC Chapter &OBJECTIVE-C

Summary of new features of Objective-c

1.nonnull

Nonnull: Mark the current property is not empty, let the outside world rest assured that use, only for marking, even if empty, also wood has the way
Equivalent to Swift inside! No.

@property (nonnull, nonatomic, strong) NSString *name;

2.nullable
Nullable: Indicates that the current attribute may be empty, let the outside world use the note
Equivalent to the inside of Swift? No.

@property (Nullable, nonatomic, strong) NSString *petname;

3.<person *>
A bit like the combination of generics and IDs to tell developers what ghosts are inside the array
Represents the object within the array is the type of the kind, which is not required to be strongly transferred from the parent class to the subclass when used by the developer

@property (Nullable, nonatomic, strong) Nsarray<person *> *friends;

iOS Development--a summary of the new features of the grammar OC Chapter &OBJECTIVE-C