iOS【webView 加载微信文章注入JS实现交互 浏览图片及保存】

iOS【webView 加载微信文章注入JS实现交互 浏览图片及保存】。最近项目某个模块中要求可以实现对网页中图片的查看，并要求在多张图片的情况下可以实现滑动浏览。
所以，问题的集中点就是如何获取所有的图片地址及添加图片的点击事件。不多说，直接上码！

在网页加载完成时，通过js获取图片和添加点击的识别方式

- (void)webViewDidFinishLoad:(UIWebView *)webView {
    [IDProgressHUD IDPlaceViewHideDirect:self.view];

    //这里是js，主要目的实现对url的获取
    static  NSString * const jsGetImages =
    @"function getImages(){\
    var objs = document.getElementsByTagName(\"img\");\
    var imgScr = '';\
    for(var i=0;i<objs.length;i&#43;&#43;){\ imgscr="imgScr" &#43;="" objs[i].src="" '&#43;';\="" };\="" return="" imgscr;\="" };";="" [webview="" stringbyevaluatingjavascriptfromstring:jsgetimages];="" 注入js方法="" nsstring="" *urlresurlt="[webView" stringbyevaluatingjavascriptfromstring:@"getimages()"];="" murlarray="[NSMutableArray" arraywitharray:[urlresurlt="" componentsseparatedbystring:@"&#43;"]];="" if="" (murlarray.count="">= 2) {
        [mUrlArray removeLastObject];
    }
    //urlResurlt 就是获取到得所有图片的url的拼接；mUrlArray就是所有Url的数组

    //添加图片可点击js
    [mWebView stringByEvaluatingJavaScriptFromString:@"function registerImageClickAction(){\
     var imgs=document.getElementsByTagName('img');\
     var length=imgs.length;\
     for(var i=0;i<length;i&#43;&#43;){\ img="imgs[i];\" img.onclick="function(){\" window.location.href="image-preview:" &#43;this.src}\="" }\="" }"];="" [mwebview="" stringbyevaluatingjavascriptfromstring:@"registerimageclickaction();"];="" }="" 

//在这个方法中捕获到图片的点击事件和被点击图片的url

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

    //预览图片
    if ([request.URL.scheme isEqualToString:@"image-preview"]) {
        NSString* path = [request.URL.absoluteString substringFromIndex:[@"image-preview:" length]];
        path = [path stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
        //path 就是被点击图片的url
        return NO;
    }
    return YES;
}

以下是保存所在作用域的图片

    //添加长按事件
    UILongPressGestureRecognizer *longPressed = [[UILongPressGestureRecognizer alloc]
                                                 initWithTarget:self action:@selector(longPressed:)];
    longPressed.minimumPressDuration = 0.3;
    longPressed.delegate = self;
    [webView addGestureRecognizer:longPressed];

    /**
 获取长按事件所在的位置图片
 */
- (void)longPressed:(UILongPressGestureRecognizer*)recognizer
{
    if (recognizer.state != UIGestureRecognizerStateBegan) {
        return;
    }
    CGPoint touchPoint = [recognizer locationInView:_webView];
    NSString *imgURL = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).src",
                        touchPoint.x, touchPoint.y];
    NSString *webImage = [_webView stringByEvaluatingJavaScriptFromString:imgURL];

    if([webImage rangeOfString:@"player"].location !=NSNotFound || webImage.length == 0){
        return;
    }
    [self showImageOptionsWithUrl:webImage];
}

- (void)showImageOptionsWithUrl:(NSString *)imageUrl
{
    _webImageURL = imageUrl;
    IBActionSheet *standardIBAS = [[IBActionSheet alloc] initWithTitle:nil delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:@"保存图片" otherButtonTitles:nil];
    [standardIBAS setFont:FontWithSize(SIZE_FONT_CONTENT)];
    [standardIBAS setTitleFont:FontWithSize(SIZE_FONT_SUBCONTENT)];
    [standardIBAS setButtonTextColor:[UIColor blackColor]];
    [standardIBAS showInView:self.navigationController.view];
}


#pragma mark - IBActionSheetDelegate

-(void)actionSheet:(IBActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex{

    if (buttonIndex == 0) {

        NSURL *url = [NSURL URLWithString:_webImageURL];
        NSURLSessionConfiguration * configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
        NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration delegate:self delegateQueue:[NSOperationQueue new]];
        NSURLRequest *imgRequest = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReturnCacheDataElseLoad timeoutInterval:30.0];

        NSURLSessionDownloadTask  *task = [session downloadTaskWithRequest:imgRequest completionHandler:^(NSURL * _Nullable location, NSURLResponse * _Nullable response, NSError * _Nullable error) {
            if (error) {
                return ;
            }
            NSData * imageData = [NSData dataWithContentsOfURL:location];
            dispatch_async(dispatch_get_main_queue(), ^{
                UIImage * image = [UIImage imageWithData:imageData];
                UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
            });   
        }];
        [task resume];
    }
}

后记：js挺好玩，我相信以后还会去多接触它。