設計模式系列文章

1、概念描述

簡單工廠模式是由一個工廠對象決定創建出哪一種產品類的實例。

2、場景舉例

馬戲團有dog和duck兩只動物，團長向馴獸師下指令，指定哪一只動物進行表演

3、代碼實現

各個類的說明：

  SIMAnimalProtocol：定義協議
  SIMAnimalFactory：工廠類（馴獸師）
  SIMAnimal：動物父類
  SIMAnimalDog：小狗
  SIMAnimalDuck：小鴨
  SIMViewController：控制器（團長）

SIMAnimalProtocol：

//具體代碼：
#import <Foundation/Foundation.h>

@protocol SIMAnimalProtocol <NSObject>

- (void)animalWalk; //動物走
- (void)animalBark; //動物叫

@end

SIMAnimal.h

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

@interface SIMAnimal : NSObject<SIMAnimalProtocol>

@property (strong, nonatomic) NSString *walkStr;
@property (strong, nonatomic) NSString *barkStr;

@end

SIMAnimal.m

#import "SIMAnimal.h"

@implementation SIMAnimal

- (void)animalWalk {
    self.walkStr = @"我們走";
}

- (void)animalBark {
    self.barkStr = @"叫一聲";
}

@end

SIMAnimalDog.h

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

@interface SIMAnimalDog : SIMAnimal

@end

SIMAnimalDog.m

#import "SIMAnimalDog.h"

@implementation SIMAnimalDog

- (void)animalWalk {
    [super animalWalk];
    NSLog(@"旺財，%@", self.walkStr);
}

- (void)animalBark {
    [super animalBark];
    NSLog(@"旺財，%@", self.barkStr);
}

@end

SIMAnimalDuck.h

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

@interface SIMAnimalDuck : SIMAnimal

@end

SIMAnimalDuck.m

#import "SIMAnimalDuck.h"

@implementation SIMAnimalDuck

- (void)animalWalk {
    [super animalWalk];
    NSLog(@"duck，%@", self.walkStr);
}

- (void)animalBark {
    [super animalBark];
    NSLog(@"duck，%@", self.barkStr);
}

@end

SIMAnimalFactory.h

#import <Foundation/Foundation.h>
#import "SIMAnimal.h"
#import "SIMAnimalDog.h"
#import "SIMAnimalDuck.h"

typedef NS_ENUM(NSUInteger, AnimalType) {
    AnimalType_dog,
    AnimalType_duck,
};

@interface SIMAnimalFactory : NSObject

+ (SIMAnimal *)assignAnimalWithType:(AnimalType)animalType;

@end

SIMAnimalFactory.m

#import "SIMAnimalFactory.h"

@implementation SIMAnimalFactory

+ (SIMAnimal *)assignAnimalWithType:(AnimalType)animalType {
    SIMAnimal *animal;
    switch (animalType) {
        case AnimalType_dog:
            animal = [[SIMAnimalDog alloc] init];
            break;
            
        case AnimalType_duck:
            animal = [[SIMAnimalDuck alloc] init];
            break;
            
        default:
            break;
    }
    return animal;
}

@end

SIMViewController.h

#import <UIKit/UIKit.h>

@interface SIMViewController : UIViewController

@end

SIMViewController.m

#import "SIMViewController.h"
#import "SIMAnimalFactory.h"

@interface SIMViewController ()

@end

@implementation SIMViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self dogShow];
    [self duckShow];
}

- (void)dogShow {
    SIMAnimal *animal = [SIMAnimalFactory assignAnimalWithType:AnimalType_dog];
    [animal animalBark];
    [animal animalWalk];
}

- (void)duckShow {
    SIMAnimal *animal = [SIMAnimalFactory assignAnimalWithType:AnimalType_duck];
    [animal animalBark];
    [animal animalWalk];
}

@end

打印結果：

簡單工廠模式.png