webView a标签保存图片

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- (BOOL)webView:(UIWebView *)webView
    shouldStartLoadWithRequest:(NSURLRequest *)request
                navigationType:(UIWebViewNavigationType)navigationType {
    //拦截href图片地址
    NSString *url = request.URL.relativeString;
    if ([url hasPrefix:@"data:"]) {
        [self saveImg:url];
        return NO;
    }
    return YES;
}

//保存图片

-(void)saveImg:(NSString *)imageUrl{
    NSLog(@"image url：%@",imageUrl);
    NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:imageUrl]];
    UIImage *image = [UIImage imageWithData:data];
    if (image) {
        [AlertView alertTitle:@"提示" message:@"保存图片至相册" sureTitle:@"确定" sureAction:^{
            [self savePhotoToAlbumWithImageUrl:imageUrl];
        } cancelTitle:@"取消"];
    }

}

//保存到相册

- (void)savePhotoToAlbumWithImageUrl:(NSString *)url{
    NSURL *imgUrl = [NSURL URLWithString:url];
    NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
    NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration delegate:self delegateQueue:[NSOperationQueue new]];
    NSURLRequest *request = [NSURLRequest requestWithURL:imgUrl cachePolicy:NSURLRequestReturnCacheDataElseLoad timeoutInterval:30.0];
    NSURLSessionDownloadTask *task = [session downloadTaskWithRequest:request completionHandler:^(NSURL * _Nullable location, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        if (error) {
            return ;
        }
        NSData *imgData = [NSData dataWithContentsOfURL:location];
        dispatch_async(dispatch_get_main_queue(), ^{
            UIImage *img = [UIImage imageWithData:imgData];
            UIImageWriteToSavedPhotosAlbum(img, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
        });
    }];
    [task resume];
}

- (void)image: (UIImage *) image didFinishSavingWithError: (NSError *) error contextInfo: (void *) contextInfo{
    if(error != NULL){
        [AlertView alertTitle:@"保存图片失败"];
    }else{
        [AlertView alertTitle:@"保存图片成功"];
    }
}

webView长按图片下载

//长按保存图片
- (void)longPressed:(UITapGestureRecognizer*)recognizer
{
    if (recognizer.state != UIGestureRecognizerStateBegan) {
        return;
    }
    CGPoint touchPoint = [recognizer locationInView:self.webView];
    NSString *js = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).src", touchPoint.x, touchPoint.y];
    NSString *imageUrl = [self.webView stringByEvaluatingJavaScriptFromString:js];
    if (imageUrl.length == 0) {
        return;
    }
    NSLog(@"image url：%@",imageUrl);
    NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:imageUrl]];
    
    UIImage *image = [UIImage imageWithData:data];
    if (image) {
      [self saveImg: imageUrl];
        //......
        //save image or Extract QR code
    }
}

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