把UIWebView内容保存图片

 //    CGSize sixzevid=CGSizeMake(1024,1100);
    CGSize imageSize = [UIScreen mainScreen].applicationFrame.size;
    
    UIGraphicsBeginImageContext(imageSize);
    [webView.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    NSData *imageData = UIImagePNGRepresentation(viewImage);

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);

    NSString *documentsDirectory = [paths objectAtIndex:0];
    
    NSString *pathFloder = [[NSString alloc] initWithString:[NSString stringWithFormat:@"web_%d.png",[[NSDate date] timeIntervalSince1970]*1000]]; 
    NSString *defaultDBPath = [documentsDirectory stringByAppendingPathComponent:pathFloder];
    
    image.image = viewImage;
//    [image initWithImage:viewImage];
    
    [imageData writeToFile:defaultDBPath atomically:YES]; 

//遗憾的是这这段代码只能保存可视的内容，不能保存整个个Web内容。