【代码笔记】单例

#import <Foundation/Foundation.h>

@interface NetManager : NSObject

+ (id)sharedManager;

-(void)firstPrintf;
-(void)secondPrintf;
-(void)threeprintf;
-(void)fourprintf;

@end

#import "NetManager.h"

static NetManager *manager;

@implementation NetManager

#pragma mark - 获取单例
+ (id)sharedManager{
if (!manager) {
manager = [[NetManager alloc]init];
}
return manager;
}

-(void)firstPrintf
{
NSLog(@"first Printf!!!!");
}
-(void)secondPrintf
{
NSLog(@"second printf!!!!!");
}
-(void)threeprintf
{
NSLog(@"three printf!!!!!!!");
}
-(void)fourprintf
{
NSLog(@"fourprintf!!!!!!");
}

#import <UIKit/UIKit.h>

@interface RootViewController : UIViewController

@end

#import "RootViewController.h"

//加上单例的头文件
#import "NetManager.h"

@interface RootViewController ()

@end

@implementation RootViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}

- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.

//单例的用法，单例中的函数，可以在程序中直接使用。
[[NetManager sharedManager] firstPrintf];
[[NetManager sharedManager] secondPrintf];
[[NetManager sharedManager] threeprintf];
[[NetManager sharedManager] fourprintf];
}

- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

2015-10-13 13:55:17.551 单例[7675:197760] first Printf!!!!
2015-10-13 13:55:17.551 单例[7675:197760] second printf!!!!!
2015-10-13 13:55:17.551 单例[7675:197760] three printf!!!!!!!
2015-10-13 13:55:17.551 单例[7675:197760] fourprintf!!!!!!