UIWebView获取所点位置图片URL

原文：http://blog.csdn.net/favormm/article/details/6614441 中有可能不触发action方法，本人稍作改动。

UIWebView有自己的UIResgure，如果我们手动加入自己的GestureRecognize将不能识别，如UILongPressGestureRecongnizer. 在浏览网页的时候，如果看到喜欢的图片，想把它保存下来如何办呢？ 我们可以自己写一个程序来实现，用uiwebview开发一个自己的浏览器。

关面说到uiwebview不能识别long press gesture，幸好有一个可以识别，那就是double click.因此我们注册它，代码如下：

    UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(doubleTap:)]; 
    doubleTap.numberOfTouchesRequired = 1; 
    doubleTap.numberOfTapsRequired = 2;
    doubleTap.delegate = self;
    [self.webView addGestureRecognizer:doubleTap]; 
    [doubleTap release];

然后就是实现doubleTap:

-(void)doubleTap:(UITapGestureRecognizer*) sender 
{ 
    // <Find HTML tag which was clicked by user> 
    // <If tag is IMG, then get image URL and start saving> 
    NSLog(@"doubleTap...........");
    if(sender.numberOfTapsRequired == 2){
        int scrollPositionY = [[self.webView stringByEvaluatingJavaScriptFromString:@"window.pageYOffset"] intValue]; 
        int scrollPositionX = [[self.webView stringByEvaluatingJavaScriptFromString:@"window.pageXOffset"] intValue]; 
        
        int displayWidth = [[self.webView stringByEvaluatingJavaScriptFromString:@"window.outerWidth"] intValue]; 
        CGFloat scale = webView.frame.size.width / displayWidth; 
        
        CGPoint pt = [sender locationInView:self.webView]; 
        pt.x *= scale; 
        pt.y *= scale; 
        pt.x += scrollPositionX; 
        pt.y += scrollPositionY; 
        
        NSString *js = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).tagName", pt.x, pt.y]; 
        NSString * tagName = [self.webView stringByEvaluatingJavaScriptFromString:js];
        NSLog(@"----------------js------%@",js);
        NSLog(@"----------------tagName------%@",tagName);
        if ([tagName isEqualToString:@"img"]||[tagName isEqualToString:@"IMG"]) { 
            NSString *imgURL = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).src", pt.x, pt.y]; 
            NSString *urlToSave = [self.webView stringByEvaluatingJavaScriptFromString:imgURL]; 
            NSLog(@"image url=%@", urlToSave); 
            self.imgUrlPath = urlToSave;
            UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:nil delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:nil otherButtonTitles:@"保存图片至相册",nil];
            [actionSheet setActionSheetStyle:UIActionSheetStyleDefault];
            [actionSheet showInView:self.view.window];
            [actionSheet release];
        } 
    }
} 

如果UITapGestureRecognizer不触发action就需要加入UITapGestureRecognizer的delegate中的一个方法：

-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer 
{ 
    return YES; 
}