UIWebView之获取所点位置图片URL

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 = 2;
[self.theWebView addGestureRecognizer:doubleTap];
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>
int scrollPositionY = [[self.theWebView stringByEvaluatingJavaScriptFromString:@"window.pageYOffset"] intValue];
int scrollPositionX = [[self.theWebView stringByEvaluatingJavaScriptFromString:@"window.pageXOffset"] intValue];

int displayWidth = [[self.theWebView stringByEvaluatingJavaScriptFromString:@"window.outerWidth"] intValue];
CGFloat scale = theWebView.frame.size.width / displayWidth;

CGPoint pt = [sender locationInView:self.theWebView];
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.theWebView stringByEvaluatingJavaScriptFromString:js];
if ([tagName isEqualToString:@"img"]) {
NSString *imgURL = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).src", pt.x, pt.y];
NSString *urlToSave = [self.theWebView stringByEvaluatingJavaScriptFromString:imgURL];
NSLog(@"image url=%@", urlToSave);
}
}

这样我们就可以得到图片的url,然后下载保存就行了。