从iOS理解工厂和抽象工厂

image.png

如上图所示，外面红色大框是抽象工厂，里面小框是工厂。

工厂

工厂：我们在创建对象时不会对客户端暴露创建逻辑，并且是通过使用一个共同的接口来指向新创建的对象。

工厂代码演示：

---------------XiaoMiPhone---------------
#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface XiaoMiPhone : NSObject
- (void)create;
@end

NS_ASSUME_NONNULL_END

#import "XiaoMiPhone.h"

@implementation XiaoMiPhone
- (void)create {
    NSLog(@"create-XiaoMiPhone");
}
@end

---------------RedMiPhone---------------
#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface RedMiPhone : NSObject
- (void)create;
@end

NS_ASSUME_NONNULL_END

#import "RedMiPhone.h"

@implementation RedMiPhone
- (void)create {
    NSLog(@"create-RedMiPhone");
}
@end

#import <Foundation/Foundation.h>

typedef NS_ENUM(NSInteger,PhoneFactoryType) {
    PhoneTypeXiaoMi = 0,
    PhoneTypeRedMi,
};

---------------XiaoMiPhoneFactory----------------
NS_ASSUME_NONNULL_BEGIN

@interface XiaoMiPhoneFactory : NSObject
+ (id)createPhone:(PhoneFactoryType)type;
@end

NS_ASSUME_NONNULL_END

#import "XiaoMiPhoneFactory.h"
#import "XiaoMiPhone.h"
#import "RedMiPhone.h"

@implementation XiaoMiPhoneFactory
+ (id)createPhone:(PhoneFactoryType)type {
    switch (type) {
        case PhoneTypeXiaoMi:
        {
            return [XiaoMiPhone new];
        }
            break;
        case PhoneTypeRedMi:
        {
            return [RedMiPhone new];
        }
            break;
        default:
            break;
    }
}
@end

使用：
  XiaoMiPhone *xPhone = [XiaoMiPhoneFactory createPhone:PhoneTypeXiaoMi];
  RedMiPhone *rPhone = [XiaoMiPhoneFactory createPhone:PhoneTypeRedMi];
    [xPhone create];
    [rPhone create];

抽象工厂

抽象工厂：是围绕一个超级工厂创建其他工厂。该超级工厂又称为其他工厂的工厂。这种类型的设计模式属于创建型模式，它提供了一种创建对象的最佳方式。
工厂代码演示：

---------------XiaoMiTvFactory---------------
#import <Foundation/Foundation.h>
typedef NS_ENUM(NSInteger,TvFactoryType) {
    TvType4A = 0,
    TvType5A,
};
NS_ASSUME_NONNULL_BEGIN

@interface XiaoMiTvFactory : NSObject
+ (id)createPhone:(TvFactoryType)type;
@end

NS_ASSUME_NONNULL_END

#import "XiaoMiTvFactory.h"
#import "XiaoMi4ATv.h"
#import "XiaoMi5ATv.h"

@implementation XiaoMiTvFactory
+ (id)createPhone:(TvFactoryType)type {
    switch (type) {
        case TvType4A:
        {
            return [XiaoMi4ATv new];
        }
            break;
        case TvType5A:
        {
            return [XiaoMi5ATv new];
        }
            break;
        default:
            break;
    }
}
@end

---------------XiaoMi5ATv---------------
#import <Foundation/Foundation.h>
NS_ASSUME_NONNULL_BEGIN

@interface XiaoMi5ATv : NSObject
- (void)create;
@end

NS_ASSUME_NONNULL_END

#import "XiaoMi5ATv.h"
@implementation XiaoMi5ATv
- (void)create {
    NSLog(@"create-XiaoMi5ATv");
}
@end

---------------XiaoMi4ATv---------------
#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface XiaoMi4ATv : NSObject
- (void)create;
@end

NS_ASSUME_NONNULL_END

#import "XiaoMi4ATv.h"

@implementation XiaoMi4ATv
- (void)create {
    NSLog(@"create-XiaoMi4ATv");
}
@end

---------------XiaoMiFactory---------------
#import <Foundation/Foundation.h>
typedef NS_ENUM(NSInteger,XiaoMiFactoryType) {
    XiaoMiTypePhone = 0,
    XiaoMiTypeTv,
};
NS_ASSUME_NONNULL_BEGIN

@interface XiaoMiFactory : NSObject
+ (Class)createFactory:(XiaoMiFactoryType)type;
@end

NS_ASSUME_NONNULL_END

#import "XiaoMiFactory.h"
#import "XiaoMiPhoneFactory.h"
#import "XiaoMiTvFactory.h"

@implementation XiaoMiFactory
+ (Class)createFactory:(XiaoMiFactoryType)type {
    switch (type) {
        case XiaoMiTypePhone:
        {
            return [XiaoMiPhoneFactory class];
        }
            break;
        case XiaoMiTypeTv:
        {
            return [XiaoMiTvFactory class];
        }
            break;
        default:
            break;
    };
}