需求：ios单例模式实现

需求：oc如何实现单例模式

.h文件

#import <Foundation/Foundation.h>

@interface SingletonObject : NSObject

+(SingletonObject *)getInstance;

@end

.m文件

#import "SingletonObject.h"

@implementation SingletonObject

+(SingletonObject *)getInstance{
    static SingletonObject *instance = nil;
    static dispatch_once_t once_token = 0;
    dispatch_once(&<span style="font-family: Arial, Helvetica, sans-serif;">once_token</span>, ^{
        instance = [[super allocWithZone:NULL]init];
    });
    return instance;
}

+ (id)allocWithZone:(struct _NSZone *)zone{
    return [self getInstance];
}
@end

测试代码main.m 文件

#import <Foundation/Foundation.h>
#import "SingletonObject.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // insert code here...
        SingletonObject *obj1 = [SingletonObject getInstance];
        NSLog(@"obj1=%@",obj1);
        SingletonObject *obj2 = [SingletonObject getInstance];
        NSLog(@"obj1=%@",obj2);
        SingletonObject *obj3 = [[SingletonObject alloc]init];
        NSLog(@"obj1=%@",obj3);
        SingletonObject *obj4 = [[SingletonObject allocWithZone:nil]init];
        NSLog(@"obj1=%@",obj4);

        NSLog(@"%d,%d,%d",obj4==obj3,obj3==obj2,obj2==obj1);
    }
    return 0;
}

参考网址：

http://sjpsega.com/blog/2014/05/25/singleton-in-ios/

demo源码：

https://github.com/Thinkerfans/OC-pattern-singleton