1.ARC 單例模式
1.1ARC 單例模式
Person.h
#import <Foundation/Foundation.h>
@interface Person : NSObject
/** 名字 */
@property (nonatomic, strong) NSString *name;
@property (nonatomic, copy) NSString *city;
+ (instancetype)sharedPerson;
@end
Person.m
#import "Person.h"
@interface Person() <NSCopying>
@end
@implementation Person
static Person *_person;
+ (instancetype)allocWithZone:(struct _NSZone *)zone
{
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
_person = [super allocWithZone:zone];
});
return _person;
}
+ (instancetype)sharedPerson
{
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
_person = [[self alloc] init];
});
return _person;
}
- (id)copyWithZone:(NSZone *)zone
{
return _person;
}
@end
ViewController.m
#import "ViewController.h"
#import "Person.h"
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
Person *person1 = [[Person alloc] init];
person1.name = @"jack";
NSMutableString *stringM = [NSMutableString stringWithFormat:@""];
[stringM appendString:@"china"];
[stringM appendString:@"beijing"];
person1.city = stringM;
Person *person2 = [[Person alloc] init];
Person *person3 = [[Person alloc] init];
Person *person4 = [[Person alloc] init];
NSLog(@"%p %p %p %p", person1, person2, person3, person4);
NSLog(@"%@ %@", person3.name,person3.city);
NSLog(@"%@ %@", [Person sharedPerson], [Person sharedPerson]);
}
@end
ARC單粒模式[16876:372799] 0x7fb3f3f37e80 0x7fb3f3f37e80 0x7fb3f3f37e80 0x7fb3f3f37e80
ARC單粒模式[16876:372799] jack chinabeijing
ARC單粒模式[16876:372799] <Person: 0x7fb3f3f37e80> <Person: 0x7fb3f3f37e80>
1.2宏抽取 ARC 單例模式
Singleton.h
// .h文件
#define SingletonH + (instancetype)sharedInstance;
// .m文件
#define SingletonM \
static id _instace; \
\
+ (instancetype)allocWithZone:(struct _NSZone *)zone \
{ \
static dispatch_once_t onceToken; \
dispatch_once(&onceToken, ^{ \
_instace = [super allocWithZone:zone]; \
}); \
return _instace; \
} \
\
+ (instancetype)sharedInstance \
{ \
static dispatch_once_t onceToken; \
dispatch_once(&onceToken, ^{ \
_instace = [[self alloc] init]; \
}); \
return _instace; \
} \
\
- (id)copyWithZone:(NSZone *)zone \
{ \
return _instace; \
}
Person.h
#import <Foundation/Foundation.h>
#import "Singleton.h"
@interface Person : NSObject
/** 名字 */
@property (nonatomic, strong) NSString *name;
@property (nonatomic, copy) NSString *city;
SingletonH
@end
Person.m
#import "Person.h"
@interface Person() <NSCopying>
@end
@implementation Person
SingletonM
@end
NSLog(@"%@ %@ %@ %@",[[Person alloc] init],
[Person new],
[[[Person alloc] init] copy],
[Person sharedInstance]);
<Person: 0x7fc391e02f90> <Person: 0x7fc391e02f90> <Person: 0x7fc391e02f90> <Person: 0x7fc391e02f90>
1.3宏抽取 ARC 單例模式
Singleton.h
// .h文件
#define SingletonH(name) + (instancetype)shared##name;
// .m文件
#define SingletonM(name) \
static id _instance; \
\
+ (instancetype)allocWithZone:(struct _NSZone *)zone \
{ \
static dispatch_once_t onceToken; \
dispatch_once(&onceToken, ^{ \
_instance = [super allocWithZone:zone]; \
}); \
return _instance; \
} \
\
+ (instancetype)shared##name \
{ \
static dispatch_once_t onceToken; \
dispatch_once(&onceToken, ^{ \
_instance = [[self alloc] init]; \
}); \
return _instance; \
} \
\
- (id)copyWithZone:(NSZone *)zone \
{ \
return _instance; \
}
Person.h
#import <Foundation/Foundation.h>
#import "Singleton.h"
@interface Person : NSObject
/** 名字 */
@property (nonatomic, strong) NSString *name;
@property (nonatomic, copy) NSString *city;
SingletonH(Person)
@end
Person.m
#import "Person.h"
@interface Person() <NSCopying>
@end
@implementation Person
SingletonM(Person)
@end
ViewController.h
#import <UIKit/UIKit.h>
#import "Singleton.h"
@interface ViewController : UIViewController
SingletonH(ViewController)
@end
ViewController.m
#import "ViewController.h"
#import "Person.h"
@implementation ViewController
SingletonM(ViewController)
- (void)viewDidLoad {
[super viewDidLoad];
NSLog(@"%@ %@ %@ %@", [[ViewController alloc] init],
[ViewController new],
[[[ViewController alloc] init] copy],
[ViewController sharedViewController]);
NSLog(@"%@ %@ %@ %@",[[Person alloc] init],
[Person new],
[[[Person alloc] init] copy],
[Person sharedPerson]);
}
<ViewController: 0x7f897be9a120> <ViewController: 0x7f897be9a120> <ViewController: 0x7f897be9a120> <ViewController: 0x7f897be9a120>
<Person: 0x7f897bf19520> <Person: 0x7f897bf19520> <Person: 0x7f897bf19520> <Person: 0x7f897bf19520>
@end
