iOS9 new Features

Ns_assume_nonnull_begin

Ns_assume_nonnull_end

A property assignment must not be null between these two

Null_resettable allow set to be empty get not empty requires overriding set method

@property (null_resettable,strong,nonatomic) nsmutablearray * ALLDETAILDATA;
@property (null_resettable,strong,nonatomic) nsmutablearray * ALLDETAILDATA;

Nonnull property assignment can not be null to the opposite nullable can be
@property (nonnull,strong,nonatomic) nsmutablearray * ALLDETAILDATA;

Generic type
You can set the properties of an object by setting data assignments in some collections

The benefit of the @property (strong,nonatomic) nsarray<nsstring*>*explainarray;//warning only for strings is that the array can be directly obtained when the data is obtained

@property (Nonatomic,strong) nsdictionary<nsstring*,nsnumber*> *dic; key is the string value is number

Custom generics

#import <Foundation/Foundation.h>

@interface Car<objecttype>: nsobject
-(void) Add: (ObjectType) name;
@end

__covariant small type turn large type

__contravariant big change Small No warning

__kindof

__kindof tells the compiler that it can be a nsstring or a subclass of NSString
-(__kindof nsstring*) text;

Native Example (TableView remove a cell)

-(Nullable __kindof UITableViewCell *) Cellforrowatindexpath: (Nsindexpath *) Indexpath; Returns nil if cell is no visible or index path is out of range

[TableView Cellforrowatindexpath:[nsindexpath indexpathforitem:0 insection:0];

iOS9 new Features