Object-C 单例模式

标准模版代码：

// Singleton.h文件

#import <Foundation/Foundation.h>

@interface Singleton : NSObject

+ (Singleton*)sharedManager;

@property (nonatomic, strong) NSString* singletonData;

@end

// Singleton.m

#import "Singleton.h"

@implementation Singleton

@synthesize singletonData = _singletonData;

static Singleton *sharedManager = nil;

+ (Singleton*)sharedManager

{

    static dispatch_once_t once;

    dispatch_once(&once, ^{

        sharedManager = [[self alloc] init];

    });

    return sharedManager;

}

@end