实例解析设计模式中的外观模式在iOS App开发中的运用

@interface SubSystemOne:NSObject
-(void)MethodOne;
@end

@implementation SubSystemOne
-(void)MethodOne{
    NSLog(@"子系统方法一");
}
@end

@interface SubSystemTwo:NSObject
-(void)MethodTwo;
@end

@implementation SubSystemTwo
-(void)MethodTwo{
    NSLog(@"子系统方法二");
}
@end

@interface SubSystemThree:NSObject
-(void)MethodThree;
@end

@implementation SubSystemThree
-(void)MethodThree{
    NSLog(@"子系统方法三");
}
@end

@interface SubSystemFour:NSObject
-(void)MethodFour;
@end

@implementation SubSystemFour
-(void)MethodFour{
    NSLog(@"子系统方法四");
}
@end

@class SubSystemOne;//此处@class关键字的作用是声明(不是定义哦)所引用的类
@class SubSystemTwo;
@class SubSystemThree;
@class SubSystemFour;
@interface Facade :NSObject{
@private SubSystemOne *one;
@private SubSystemTwo *two;
@private SubSystemThree *three;
@private SubSystemFour *four;
}
-(Facade*)MyInit;
-(void)MethodA;
-(void)MethodB;
@end

@implementation Facade
-(Facade*)MyInit{
    one= [[SubSystemOne alloc]init];
    two= [[SubSystemTwo alloc]init];
    three= [[SubSystemThree alloc]init];
    four= [[SubSystemFour alloc]init];
    return self;
}
-(void)MethodA{
    NSLog(@"\n方法组A() ---- ");
    [one MethodOne];
    [two MethodTwo];
    [three MethodThree];
    [four MethodFour];
}
-(void)MethodB{
    NSLog(@"\n方法组B() ---- ");
    [two MethodTwo];
    [three MethodThree];
}
@end

int main (int argc,const char * argv[])
{
    @autoreleasepool{
        Facade *facade = [[Facade alloc]MyInit];
        [facade MethodA];
        [facade MethodB];
    }
    return 0;
}

- (void)addAlbum:(Album*)album atIndex:(int)index
{
    [persistencyManager addAlbum:album atIndex:index];
    if (isOnline)
    {
        [httpClient postRequest:@"/api/addAlbum" body:[album description]];
    }
}

- (void)deleteAlbumAtIndex:(int)index
{
    [persistencyManager deleteAlbumAtIndex:index];
    if (isOnline)
    {
        [httpClient postRequest:@"/api/deleteAlbum" body:[@(index) description]];
    }
}