application is modifying the autolayout engine from a background thread解決方案

標籤：

NSURLSession *session = [NSURLSession sharedSession];    __weak id safeSelf = self;    NSURLSessionDataTask *task = [session dataTaskWithRequest:req completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {        self.webData = data;        if (self.webData) {            // 如果擷取到了資料            NSXMLParser *paser = [[NSXMLParser alloc]initWithData:self.webData];            paser.delegate = self;            [paser parse];        }                if ([self.parseResults isEqualToString:@"false"]) {            UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"登入失敗" message:@"帳號密碼錯誤" preferredStyle:UIAlertControllerStyleAlert];            UIAlertAction *action = [UIAlertAction actionWithTitle:@"oops" style:UIAlertActionStyleDefault handler:nil];            [alert addAction:action];            //dispatch_async(dispatch_get_main_queue(), ^{                [self presentViewController:alert animated:YES completion:nil];            //});                    }            }];    [task resume];    

[self presentViewController:alert animated:YES completion:nil]語句報錯，資訊為：

application is modifying the autolayout engine from a background thread, which can lead to engine corruption and weird crashes.  This will cause an exception in a future release.

解決方案：

  dispatch_async(dispatch_get_main_queue(), ^{                [self presentViewController:alert animated:YES completion:nil];            });

 

application is modifying the autolayout engine from a background thread解決方案