类的子类超类

Question

我试图让两个子类：

// Old code 

- (void)setPaging { 
    [pagingScrollView addSubview:self.ImageScrollView]; 
} 

@interface ImageScrollView : UIScrollView <UIScrollViewDelegate> { 
    UIView  *imageView; 
    NSUInteger  index; 
} 
@property (assign) NSUInteger index; 
- (void)displayTiledImageNamed:(CGPDFPageRef)page size:(CGSize)imageSize; 
@end 

@implementation ImageScrollView 
@synthesize index; 
// ... my methods ... 
@end 

更改为：

// NEW Code__________________________________________________________* 

- (void)setPaging { 
    if (D == 1) { 
     // error: request for member 'ISVportrate' in something not a 
     // structure or union 
     [pagingScrollView addSubview:self.ISVportrate]; 
    } else if (D == 2) { 
     //error: request for member 'ISVLandscape' in something not a 
     // structure or union 
     [pagingScrollView addSubview:self.ISVLandscape]; 
    } 
} 

@class ISVportrate; 
@class ISVLandscape; 
@interface ImageScrollView : UIScrollView <UIScrollViewDelegate> { 
    UIView  *imageView; 
    NSUInteger  index; 
} 
@property (assign) NSUInteger index; 
- (void)displayTiledImageNamed:(CGPDFPageRef)page size:(CGSize)imageSize; 
@end 
@interface ISVportrate : ImageScrollView {} 
@end 
@interface ISVLandscape : ImageScrollView {} 
@end 

@implementation ISVportrate : ImageScrollView 

// error: property 'index' attempting to use ivar 'index' declared in 
// super class of 'ISVportrate' 
@synthesize index; 

// ... my methods ... 
@end 
@implementation ISVLandscape : ImageScrollView 

// error: property 'index' attempting to use ivar 'index' declared in 
// super class of 'ISVLandscape' 
@synthesize index; 

// ... my methods ... 
@end 

我不这样做的权利，我是谁？见上面我有4个错误......这是我第一次上课......帮助我理解，我想我已经差不多了。

Answer 1

@synthesize进入ImageScrollView的@implementation，而不是在子类中。

self.ISVportrate没有意义（除非你有一个方法叫做-ISVportrate，这也没有任何意义）。

这听起来像你还没有完全熟悉面向对象的编程。你会想创建一个你的子类的适当的实例，并将其作为任何视图的子视图包含它......