iOS设计模式解析（一）工厂方法

• 工厂方法：定义创建对象的借口，让子类决定实例化哪一个类。工厂方法是一个类的实例化延迟到了子类
• 例如      ：Shoes厂有两个子类（Newbalance、Nike）构建类图如下：　　

　　

• 代码实现：

   #import "shoes.h"
  
   @implementation shoes
  
   -(instancetype)initWithFrame:(CGRect)frame{
       if (self == [super initWithFrame:frame]) {
           //牌子
           _band = @"Shoes";
       }
       return self;
   }
  
   @end

  Shoes

   #import "NewBlance.h"
  
   @implementation NewBlance
   -(instancetype)initWithFrame:(CGRect)frame{
       if (self == [super initWithFrame:frame]) {
           self.band = @"NewBlance";
       }
       return self;
   }
  
   @end

  NewBlance

   #import "Nike.h"
  
   @implementation Nike
   -(instancetype)initWithFrame:(CGRect)frame{
       if (self == [super initWithFrame:frame]) {
           self.band = @"Nike";
       }
       return self;
   }
  
   @end

  Nike

   #import "ViewController.h"
   #import "NewBlance.h"
   #import "Nike.h"
   @interface ViewController ()
  
   @end
  
   @implementation ViewController
  
   - (void)viewDidLoad {
       [super viewDidLoad];
  
       NewBlance * shoeNB   = [[NewBlance alloc]initWithFrame:CGRectZero];
       NSLog(@"%@",shoeNB.band);
  
       Nike      * shoeNike = [[Nike alloc]initWithFrame:CGRectZero];
       NSLog(@"%@",shoeNike.band);
   }
  
   - (void)didReceiveMemoryWarning {
       [super didReceiveMemoryWarning];
   }
  
   @end

  ViewController

• 打印结果：

  2016-05-09 15:49:45.109 Factory[2416:181448] NewBlance

  2016-05-09 15:49:45.110 Factory[2416:181448] Nike