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- (void)viewDidLoad { [super viewDidLoad]; UIBarButtonItem *rightButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(rightButtonTapped:)]; self.navigationItem.rightBarButtonItem = rightButton; WKWebViewConfiguration *configuration = [[WKWebViewConfiguration alloc] init]; _webView = [[WKWebView alloc] initWithFrame:self.view.bounds configuration:configuration]; _webView.navigationDelegate = self; [self.view addSubview:_webView]; NSURL *url = [NSURL URLWithString:@"https://www.apple.com"]; NSURLRequest *request = [NSURLRequest requestWithURL:url]; [_webView loadRequest:request]; } - (void)rightButtonTapped:(UIBarButtonItem *)sender { NSLog(@"self.webView.scrollView.contentSize.height:%f", self.webView.scrollView.contentSize.height); WKSnapshotConfiguration* configuration = [WKSnapshotConfiguration new]; configuration.rect = CGRectMake(0, 0, self.webView.scrollView.contentSize.width, self.webView.scrollView.contentSize.height); // configuration.afterScreenUpdates = NO; [self.webView takeSnapshotWithConfiguration:configuration completionHandler:^(UIImage * _Nullable snapshotImage, NSError * _Nullable error) { if (error) { NSLog(@"fail"); } else { NSLog(@"succ"); } }]; } Running the code above, I get a blank image

NSString *jsonString = @"{\"key1\":\"value1\",\"key2\":\"value2\",\"key3\":\"value3\",\"key4\":\"value4\"}"; NSString *jsonString2 = @"{\"key2\":\"value2\",\"key1\":\"value1\",\"key4\":\"value4\",\"key3\":\"value3\"}"; NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding]; NSData *jsonData2 = [jsonString2 dataUsingEncoding:NSUTF8StringEncoding]; NSDictionary *dict1 = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:nil]; NSDictionary *dict2 = [NSJSONSerialization JSONObjectWithData:jsonData2 options:NSJSONReadingMutableContainers error:nil]; The expected results are： dict1:key1,key2,key3,key4 dict2:key2,key1,key4,key3 Is there any way to make that happen?