[IOS 下重温设计模式] AbstractFactory

@interface BrandingFactory : NSObject 
{

}

+ (BrandingFactory *) factory;

- (UIView *) brandedView;
- (UIButton *) brandedMainButton;
- (UIToolbar *) brandedToolbar;

@end

#define USE_ACME

@implementation BrandingFactory

+ (BrandingFactory *) factory
{
#if defined (USE_ACME)
    return [[[AcmeBrandingFactory alloc] init] autorelease];
#elif defined (USE_SIERRA)
    return [[[SierraBrandingFactory alloc] init] autorelease];
#else
    return nil;
#endif
}

- (UIView *) brandedView
{
    return nil;
}

- (UIButton *) brandedMainButton
{
    return nil;
}

- (UIToolbar *) brandedToolbar
{
    return nil;
}

@end

=============================

@interface SierraBrandingFactory : BrandingFactory
{
    
}

- (UIView*) brandedView;
- (UIButton*) brandedMainButton;
- (UIToolbar*) brandedToolbar;

@implementation SierraBrandingFactory

- (UIView*) brandedView
{
    // returns a custom view for Sierra
    return [[[SierraView alloc] init] autorelease];
}

- (UIButton*) brandedMainButton
{
    // returns a custom main button for Sierra
    return [[[SierraMainButton alloc] init] autorelease];
}

- (UIToolbar*) brandedToolbar
{
    // returns a custom toolbar for Sierra
    return [[[SierraToolbar alloc] init] autorelease];
}

@end

=============================

@interface AcmeBrandingFactory : BrandingFactory
{

}

- (UIView *) brandedView;
- (UIButton *) brandedMainButton;
- (UIToolbar *) brandedToolbar;

@implementation AcmeBrandingFactory

- (UIView *) brandedView
{
    // returns a custom view for Acme
    return [[[AcmeView alloc] init] autorelease];
}

- (UIButton *) brandedMainButton
{
    // returns a custom main button for Acme
    return [[[AcmeMainButton alloc] init] autorelease];
}

- (UIToolbar *) brandedToolbar
{
    // returns a custom toolbar for Acme
    return [[[AcmeToolbar alloc] init] autorelease];
}

@end

=============================

客户端：

BrandingFactory * factory = [BrandingFactory factory];
    
    UIView * view = [factory brandedView];


    UIButton * button = [factory brandedMainButton];


    UIToolbar * toolbar = [factory brandedToolbar];