UIWebView保存图片

要保存网页中的图片，关键是要获取手指点击位置的图片的url地址，这就需要从js调用oc的方法。下面介绍两种方法来实现图片保存功能，但是这两种方法都只适用于图片地址用如下形式表示才可以获取：
[图片上传失败...(image-71c880-1520910783696)]

如果图片是通过js动态生成的，就无法使用下面的方法获取

方法1、获取点击位置的图片的src属性

实现原理：
该方法主要是获取手指点击的位置，然后获取该位置的标签的src属性，如果是img标签，那么就可以获取到url。如果是其他标签，就无法获取到url属性。

        //在分线程中下载、缓存、读取  在主线程中显示图片
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
            NSData* data = [self saveServiceImage:[NSURL URLWithString:[NSString stringWithFormat:@"%@%@", kImageServerRootURL, [dic valueForKey:@"serviceIconUrl2"]]]];
            dispatch_async(dispatch_get_main_queue(), ^{
                if (data) {
                    cell.titleImage.image = [UIImage imageWithData:data];
                }
                else {
                    cell.titleImage.image = [UIImage imageNamed:@"erweima"];
                }

- (BOOL)webView:(UIWebView*)webView shouldStartLoadWithRequest:(NSURLRequest*)request navigationType:(UIWebViewNavigationType)navigationType
{

    NSString* requestString = [[request URL] absoluteString];

    NSArray* components = [requestString componentsSeparatedByString:@":"];

    if ([components count] > 1 && [(NSString*)[components objectAtIndex:0] isEqualToString:@"lfyprotocol"]) {
        if ([(NSString*)[components objectAtIndex:1] isEqualToString:@"http"] || [(NSString*)[components objectAtIndex:1] isEqualToString:@"https"]) {

            //            NSString *path = [NSString stringWithFormat:@"%@:%@:%@",[components objectAtIndex:1],[components objectAtIndex:2],[components objectAtIndex:3]];
            NSString* path = [requestString substringWithRange:NSMakeRange(12, requestString.length - 12)];
            NSMutableDictionary* dic = [[[NSMutableDictionary alloc] init] autorelease];
            [dic setObject:path forKey:@"imageURL"];
            [[NSNotificationCenter defaultCenter] postNotificationName:@"browsePhoto" object:nil userInfo:dic];
        }
        return NO;
    }
    if ([self.titleName isEqualToString:NoPaperTitle]) {

        if ([[requestString componentsSeparatedByString:@"userInfo"] count] >= 2) {
            NSArray* array = [requestString componentsSeparatedByString:@"="];
            //获取并转换所需参数
            NSString* str = [array[1] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
            NSDictionary* jsonDict = [SystemUtils jumpTowebView:str];
            // 获取fn 字符串转字典
            NSDictionary* fnDic = [imageEnarge JsonStringToDict:array[1]];
            //字典转json
            NSString* jsonStr = [imageEnarge dictionaryToJson:jsonDict];
            //拼接注册函数
            NSString* stri2 = [NSString stringWithFormat:@"%@(%@);", [fnDic objectForKey:@"fn"], jsonStr];
            [webView stringByEvaluatingJavaScriptFromString:stri2];
            return NO;
        }
    }

    return YES;
}