ios 单利的完整使用实例 及销毁 宏定义

//下面这段宏考过去直接用
#define SYNTHESIZE_SINGLETON_FOR_HEADER(className) 

+ (className *)sharedInstance;
+ (void)destroyInstance;
//在单例生成之前onceToken = 0,在单例生成之后onceToken = -1了,之后一直保持-1这个值,知道这个之后我想你应该有思路了
#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 协议
import <Foundation/Foundation.h>
@interface YNHTUserModel : NSObject<NSCopying,NSMutableCopying>
SYNTHESIZE_SINGLETON_FOR_HEADER(YNHTUserModel);
@property (nonatomic,copy) NSString* inviter_id;//邀请人ID
@property (nonatomic,copy) NSString* token;
@property (nonatomic,copy) NSString* nick_name;
@end

#import "YNHTUserModel.h"
@implementation YNHTUserModel
SYNTHESIZE_SINGLETON_FOR_CLASS(YNHTUserModel);

@end