UIWebView体系结构（五）_UIWebViewScrollView和UIWebScrollView_uiwebviewscrollview uiwebbrowserview-CSDN博客

_UIWebViewScrollView的继承链为：_UIWebViewScrollView->UIWebScrollView->UIScrollView。

通过反编译可以得到实现。_UIWebViewScrollView和UIWebScrollView的实现为：（代码好长，点此跳过）

[cpp]view plaincopy 
   
 @interface UIWebScrollView : UIScrollView  
   
 - (void)didMoveToWindow;  
 - (BOOL)touchesShouldCancelInContentView:(id)arg1;  
   
 @end  

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 @implementation UIWebScrollView  
   
 - (void)didMoveToWindow  
 {  
     [super didMoveToWindow];  
     if (!self.window)  
     {  
         SEL sel = @selector(scrollViewWasRemoved:);  
         if ([super.delegate respondsToSelector:sel])  
             objc_msgSend(super.delegate, sel, self);  
     }  
 }  
   
 - (BOOL)touchesShouldCancelInContentView:(id)arg1  
 {  
     return YES;  
 }  
   
 @end  

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 @interface _UIWebViewScrollView : UIWebScrollView  
 {  
     _UIWebViewScrollViewDelegateForwarder *_forwarder;  
     BOOL _bouncesSetExplicitly;  
     UIWebBrowserView *_browserView;  
 }  
   
 - (void)_setWebView:(id)arg1;  
 - (id)delegate;  
 - (void)setDelegate:(id)arg1;  
 - (void)setBouncesHorizontally:(BOOL)arg1;  
 - (void)setBouncesVertically:(BOOL)arg1;  
 - (void)setBounces:(BOOL)arg1;  
 - (void)_weaklySetBouncesHorizontally:(BOOL)arg1;  
 - (void)dealloc;  
 - (id)initWithFrame:(struct CGRect)arg1;  
   
 @end  

[cpp]view plaincopy 
   
 @implementation _UIWebViewScrollView  
   
 - (void)_setWebView:(id)arg1  
 {  
     [_forwarder setWebView:arg1];  
     super.delegate = nil;  
     super.delegate = _forwarder;  
 }  
   
 - (id)delegate  
 {  
     return _forwarder.delegate;  
 }  
   
 - (void)setDelegate:(id)arg1  
 {  
     _forwarder.delegate = arg1;  
     super.delegate = nil;  
     super.delegate = _forwarder;  
 }  
   
 - (void)setBouncesHorizontally:(BOOL)arg1  
 {  
     [super setBouncesHorizontally:arg1];  
     _bouncesSetExplicitly = YES;  
 }  
   
 - (void)setBouncesVertically:(BOOL)arg1  
 {  
     [super setBouncesVertically:arg1];  
     _bouncesSetExplicitly = YES;  
 }  
   
 - (void)setBounces:(BOOL)arg1  
 {  
     [super setBounces:arg1];  
     _bouncesSetExplicitly = YES;  
 }  
   
 - (void)_weaklySetBouncesHorizontally:(BOOL)arg1  
 {  
     if (!_bouncesSetExplicitly)  
         [super setBouncesHorizontally:arg1];  
 }  
   
 - (void)dealloc  
 {  
     [_forwarder release];  
     _forwarder = nil;  
     [super dealloc];  
 }  
   
 - (id)initWithFrame:(struct CGRect)arg1  
 {  
     self = [super initWithFrame:arg1];  
     if (self)  
     {  
         _forwarder = [[_UIWebViewScrollViewDelegateForwarder alloc] init];  
     }  
     return self;  
 }  
   
 @end  

UIWebScrollView比UIScrollView多做了两件事：

永远对contentView cancel touch
通知delegate自己被移出window的view hierarchy

_UIWebViewScrollView比UIWebScrollView多做了一件事：记录是否被显式设置了Bounces属性。

(UIWebScrollView有其它子类）

_UIWebViewScrollViewDelegateForwarder的实现如下：（代码好长，点此跳过）

[cpp]view plaincopy 
   
 @interface _UIWebViewScrollViewDelegateForwarder : NSObject <UIScrollViewDelegate>  
 {  
     id <UIScrollViewDelegate> _delegate;  
     UIWebView *_webView;  
 }  
   
 @property(nonatomic) UIWebView *webView; // @synthesize webView=_webView;  
 @property(nonatomic) id <UIScrollViewDelegate> delegate; // @synthesize delegate=_delegate;  
 - (void)forwardInvocation:(id)arg1;  
 - (BOOL)respondsToSelector:(SEL)arg1;  
 - (id)methodSignatureForSelector:(SEL)arg1;  
   
 @end  

[cpp]view plaincopy 
   
 @implementation _UIWebViewScrollViewDelegateForwarder  
   
 @synthesize webView=_webView;  
 @synthesize delegate=_delegate;  
   
 - (void)forwardInvocation:(NSInvocation*)arg1  
 {  
     SEL sel = [arg1 selector];  
     bool hasWebViewResponded = false;  
     if ([_webView respondsToSelector:sel])  
     {  
         [arg1 invokeWithTarget:_webView];  
         hasWebViewResponded = true;  
     }  
     if([_delegate respondsToSelector:sel])  
     {  
         [arg1 invokeWithTarget:_delegate];  
     }  
     else  
     {  
         if (!hasWebViewResponded)  
         {  
             [super forwardInvocation:arg1];  
         }  
     }  
 }  
   
 - (BOOL)respondsToSelector:(SEL)arg1  
 {  
     bool result = [super respondsToSelector:arg1];  
     if (!result)  
     {  
         result = [_webView respondsToSelector:arg1];  
         if (!result)  
         {  
             result = [_delegate respondsToSelector:arg1];  
         }  
     }  
     return result;  
 }  
   
 - (id)methodSignatureForSelector:(SEL)arg1  
 {  
     id result = [super methodSignatureForSelector:arg1];  
     if (!result)  
     {  
         result = [_webView methodSignatureForSelector:arg1];  
         if (!result)  
         {  
             result = [(NSObject*)_delegate methodSignatureForSelector:arg1];  
         }  
     }  
     return result;  
 }  
   
 @end  