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須讀:看完該文章你能做什么？

用宏定義抽取單例

學習前:你必須會什么?（在這里我已經默認你具備C語言的基礎了）

什么是單例

一、本章筆記

 #define 左邊 替換 右邊的
  傳遞參數 可以用(xx) 右邊用##接收
  >>> .m的抽取
  分為ARC 和 MRC處理
  動態判斷MRC

二、code

main.m

#pragma mark 22-單例宏抽取
#pragma mark 概念
/*
一、
 #define 左邊 替換 右邊的
  傳遞參數 可以用(xx) 右邊用##接收
  >>> .m的抽取
  分為ARC 和 MRC處理
  動態判斷MRC
 */
#pragma mark - 代碼
#import <Foundation/Foundation.h>
#pragma mark 類
#import "Tools.h"
#import "Person.h"
#pragma mark - main函數
int main(int argc, const char * argv[])
{
    Tools *t1 = [[Tools alloc]init]; // 內部會調用allocWithZone
    Tools *t2 = [Tools new];
    Tools *t3 = [Tools shareTools];
    Tools *t4 = [Tools copy];
    Tools *t5 = [Tools mutableCopy];
    NSLog(@"%p,%p,%p,%p,%p",t1,t2,t3,t4,t5);
    Person *p = [Person sharePerson];
    Person *p1 = [Person sharePerson];
    Person *p2 = [Person sharePerson];
    NSLog(@"%p,%p,%p",p,p1,p2);
    
    
    // 如何判斷是ARC 還是 MRC呢?
#if __has_feature(objc_arc)
    NSLog(@"ARC");
#else
    NSLog(@"MRC");
#endif
    return 0;
}

Tools

>>>.h
#import <Foundation/Foundation.h>
#import "Singleton.h"
@interface Tools : NSObject<NSCopying,NSMutableCopying>
//+ (instancetype)shareToos;
interfaceSingleton(Tools);

@end

>>>.m
#import "Tools.h"

@implementation Tools
implementationSingleton(Tools)
/*
+ (instancetype)shareTools
{
    Tools *instance = [[self alloc]init];
    return instance;
}

static Tools *_instance = nil;
+ (instancetype)allocWithZone:(struct _NSZone *)zone
{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        _instance = [super allocWithZone:zone];
    });
    return _instance;
    
}

- (id)copyWithZone:(NSZone *)zone
{
    return _instance;
}

- (id)mutableCopyWithZone:(NSZone *)zone
{
    return _instance;
}

#pragma mark MRC需要多處理
- (oneway void)release
{

}
- (instancetype)retain
{
    return _instance;
}
- (NSUInteger)retainCount
{
    return MAXFLOAT;
}
 */
@end

Person

>>>.h
#import <Foundation/Foundation.h>
#import "Singleton.h"
@interface Person : NSObject
interfaceSingleton(Person);
@end

>>>.m
#import "Person.h"

@implementation Person
implementationSingleton(Person)

@end

Singleton

>>>.h
// >>> .h的抽取
//#define 左邊 替換 右邊的
// 傳遞參數 可以用(xx) 右邊用##接收

// >>> .m的抽取
// 分為ARC 和 MRC處理
// 動態判斷MRC
/*
 #if __has_feature(objc_arc)
 NSLog(@"ARC");
 #else
 NSLog(@"MRC");
 #endif
 */

/*
 #define implementationSingleton(name) \
 + (instancetype)share##name\
 {\
 name *instance = [[self alloc]init];\
 return instance;\
 }\
 static name *_instance = nil;\
 + (instancetype)allocWithZone:(struct _NSZone *)zone\
 {\
 static dispatch_once_t onceToken;\
 dispatch_once(&onceToken, ^{\
 _instance = [super allocWithZone:zone];\
 });\
 return _instance;\
 }\
 - (id)copyWithZone:(NSZone *)zone\
 {\
 return _instance;\
 }\
 - (id)mutableCopyWithZone:(NSZone *)zone\
 {\
 return _instance;\
 }\
 - (oneway void)release\
 {\
 \
 }\
 - (instancetype)retain\
 {\
 return _instance;\
 }\
 - (NSUInteger)retainCount\
 {\
 return MAXFLOAT;\
 }\
 */

#define interfaceSingleton(name) + (instancetype)share##name

#if __has_feature(objc_arc)
#define implementationSingleton(name) \
+ (instancetype)share##name\
{\
name *instance = [[self alloc]init];\
return instance;\
}\
static name *_instance = nil;\
+ (instancetype)allocWithZone:(struct _NSZone *)zone\
{\
static dispatch_once_t onceToken;\
dispatch_once(&onceToken, ^{\
_instance = [super allocWithZone:zone];\
});\
return _instance;\
}\
- (id)copyWithZone:(NSZone *)zone\
{\
return _instance;\
}\
- (id)mutableCopyWithZone:(NSZone *)zone\
{\
return _instance;\
}
#else
#define implementationSingleton(name) \
+ (instancetype)share##name\
{\
name *instance = [[self alloc]init];\
return instance;\
}\
static name *_instance = nil;\
+ (instancetype)allocWithZone:(struct _NSZone *)zone\
{\
static dispatch_once_t onceToken;\
dispatch_once(&onceToken, ^{\
_instance = [super allocWithZone:zone];\
});\
return _instance;\
}\
- (id)copyWithZone:(NSZone *)zone\
{\
return _instance;\
}\
- (id)mutableCopyWithZone:(NSZone *)zone\
{\
return _instance;\
}\
- (oneway void)release\
{\
\
}\
- (instancetype)retain\
{\
return _instance;\
}\
- (NSUInteger)retainCount\
{\
return MAXFLOAT;\
}
#endif