//
// MusicManager.h
// OC4_单例
//
// Created by zhangxueming on 15/6/19.
// Copyright (c) 2015年 zhangxueming. All rights reserved.
//
#import <Foundation/Foundation.h>
@interface MusicManager : NSObject
//单例方法
//通常以 default 或者 shared 开头
+ (MusicManager *
)defaultMusicManager;
@end
//
// MusicManager.m
// OC4_单例
//
// Created by zhangxueming on 15/6/19.
// Copyright (c) 2015年 zhangxueming. All rights reserved.
//
#import "MusicManager.h"
static MusicManager *music=
nil;
@implementation MusicManager
//方法一:
//+ (MusicManager *)defaultMusicManager
//{
// if (music==nil) {
// music = [[MusicManager alloc] init];
// }
// return music;
//}
//方法二:
//+ (MusicManager *)defaultMusicManager
//{
// //加线程锁
// @synchronized(self)
// {
// if (music == nil) {
// music = [[MusicManager alloc] init];
// }
// }
// return music;
//}
//GCD写法
+ (MusicManager *
)defaultMusicManager
{
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^
{
if (music ==
nil) {
music =
[[MusicManager alloc] init];
}
});
//NSLog(@"onceToken = %li", onceToken);
return music;
}
@end
//
// main.m
// OC4_单例
//
// Created by zhangxueming on 15/6/19.
// Copyright (c) 2015年 zhangxueming. All rights reserved.
//
#import <Foundation/Foundation.h>
#import "MusicManager.h"
//单例类:该类创建的对象有且只有一个
int main(
int argc,
const char *
argv[]) {
@autoreleasepool {
MusicManager *m1 =
[MusicManager defaultMusicManager];
MusicManager *m2 =
[MusicManager defaultMusicManager];
MusicManager *m3 =
[MusicManager defaultMusicManager];
NSLog(@"m1 = %p m2 = %p m3 = %p", m1,m2, m3);
}
return 0;
}
转载于:https://www.cnblogs.com/0515offer/p/4589564.html
