单例的使用:
.m
为了方便实用，只要将以下代码定义在header文件或者.pch文件即可；
// .h
#define singleton_interface(class) + (instancetype)shared##class;
// .m
#define singleton_implementation(class)
static class *_instance;
+ (id)allocWithZone:(struct _NSZone *)zone
{
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
_instance = [super allocWithZone:zone];
});
return _instance;
}
+ (instancetype)shared##class
{
if (_instance == nil) {
_instance = [[class alloc] init];
}
return _instance;
}
使用方法：
Manager.h文件
#import <Foundation/Foundation.h>
@interface Manager :NSObject
singleton_interface(Manager);
@end
Manager.m文件
#import "Manager.h"
@interface Manager ()
@end
@implementation Manager
singleton_implementation(Manager)
@end
viewController调用
Manager *manager = [Manager sharedManager];