UIWebView+Additions.h

#import <UIKit/UIKit.h>


@interface UIWebView (Additions)

/*!
 @abstract   Enable/Disable the receiver from scrolling.
 */
@property (nonatomic, assign) BOOL webViewScrollEnabled;

@end

UIWebView+Additions.m

#import "UIWebView+Additions.h"


@implementation UIWebView (Additions)

- (BOOL)webViewScrollEnabled
{
    // iOS 3.2 or above
    // - UIWebView has inner UIScrollView
    //   so we can use it easily
    for (id subview in self.subviews) {
        if ([[subview class] isSubclassOfClass: [UIScrollView class]]) {
            return ((UIScrollView *)subview).scrollEnabled;
        }
    }
    
    // iOS 3.1.3 or less
    // - UIWebView doesn't contain UIScrollView
    // - UIWebView uses custom scroller class
    //   we can use its method
    // 
    // Customized the way introduced in these page
    // http://d.hatena.ne.jp/nakamura001/20090520/1242837408
    // http://praveenmatanam.wordpress.com/2009/04/03/how-to-disable-uiwebview-from-user-scrolling/
    //
    // I'm not sure the name of the getter method, probably which is "isScrollingEnabled" or "scrollingEnabled",
    // so I'm trying both of them
    
    SEL selector = @selector(isScrollingEnabled);
    
    for (id subview in self.subviews) {
        if ([subview respondsToSelector:selector]) {
            NSMethodSignature *sig = [subview methodSignatureForSelector:selector];
            NSInvocation* invocation = [NSInvocation invocationWithMethodSignature:sig];
            [invocation setTarget:subview];
            [invocation setSelector:selector];
            [invocation invoke];
            BOOL result = YES;
            [invocation getReturnValue:&result];
            return result;
        }
    }
    
    selector = @selector(scrollingEnabled);
    
    for (id subview in self.subviews) {
        if ([subview respondsToSelector:selector]) {
            NSMethodSignature *sig = [subview methodSignatureForSelector:selector];
            NSInvocation* invocation = [NSInvocation invocationWithMethodSignature:sig];
            [invocation setTarget:subview];
            [invocation setSelector:selector];
            [invocation invoke];
            BOOL result = YES;
            [invocation getReturnValue:&result];
            return result;
        }
    }
    
    // Couldn't find the current state. Maybe it's YES (the default)
    return YES;
}

- (void)setWebViewScrollEnabled:(BOOL)b
{
    // iOS 3.2 or above
    // - UIWebView has inner UIScrollView
    //   so we can use it easily
    for (id subview in self.subviews) {
        if ([[subview class] isSubclassOfClass: [UIScrollView class]]) {
            ((UIScrollView *)subview).scrollEnabled = b;
            return;
        }
    }
    
    // iOS 3.1.3 or less
    // - UIWebView doesn't contain UIScrollView
    // - UIWebView uses custom scroller class
    //   we can use its method
    // 
    // Customized the way introduced in these page
    // http://d.hatena.ne.jp/nakamura001/20090520/1242837408
    // http://praveenmatanam.wordpress.com/2009/04/03/how-to-disable-uiwebview-from-user-scrolling/
    
    SEL selector = @selector(setScrollingEnabled:);
    
    for (id subview in self.subviews) {
        if ([subview respondsToSelector:selector]) {
            NSMethodSignature *sig = [subview methodSignatureForSelector:selector];
            NSInvocation* invocation = [NSInvocation invocationWithMethodSignature:sig];
            [invocation setTarget:subview];
            [invocation setSelector:selector];
            [invocation setArgument:&b atIndex:2];
            [invocation invoke];
            return;
        }
    }
}

@end