//下面這段宏考過去直接用#define SYNTHESIZE_SINGLETON_FOR_HEADER(className) //+ (className *)sharedInstance;/+ (void)destroyInstance;//在單例生成之前onceToken = 0,在單例生成之后onceToken = -1了,之后一直保持-1這個值,知道這個之后我想你應該有思路了#define SYNTHESIZE_SINGLETON_FOR_CLASS(className) //static className *shared##className = nil; /static dispatch_once_t onceToken;/+ (className *)sharedInstance/{/ return [[self alloc] init];/}/+ (className *)allocWithZone:(struct _NSZone *)zone/{/ dispatch_once(&onceToken, ^{/  shared##className = [super allocWithZone:zone];/ });/ return shared##className;/}/- (className *)copyWithZone:(NSZone *)zone/{/ return shared##className;/}/- (className *)mutableCopyWithZone:(NSZone *)zone/{/ return shared##className;/}/+ (void)destroyInstance {/ shared##className = nil;/ onceToken = 0;/}/

//用法，注意要遵循NSCopying,NSMutableCopying 協議import <Foundation/Foundation.h>@interface YNHTUserModel : NSObject<NSCopying,NSMutableCopying>SYNTHESIZE_SINGLETON_FOR_HEADER(YNHTUserModel);@property (nonatomic,copy) NSString* inviter_id;//邀請人ID@property (nonatomic,copy) NSString* token;@property (nonatomic,copy) NSString* nick_name;@end

#import "YNHTUserModel.h"@implementation YNHTUserModelSYNTHESIZE_SINGLETON_FOR_CLASS(YNHTUserModel);@end