dispatch async code error - Objective C

ios, objective-c

Solution

Its just syntax error. Try following

- (void)alertMessage : (NSString*) message {
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Alert" message:message preferredStyle:UIAlertControllerStyleAlert];
    UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:NULL];
    [alert addAction:okAction];

    dispatch_async(dispatch_get_main_queue(), ^(void){
        [self presentViewController:alert animated:true completion:NULL];
    });

}

Problem

I am new to Objective C but have been working on Swift for a while now. I assumed Objective c to be logically similar to swift. I have to present an alert controller while I am processing a json data request; so I had to use dispatch async to get it to work in swift. Here's the code I used in Swift: ``` func alertMessage(message : String) -> Void { let alert = UIAlertController(title: "Alert", message: message, preferredStyle: .Alert) let okAction = UIAlertAction(title: "OK", style: .Default, handler: nil) alert.addAction(okAction) dispatch_async(dispatch_get_main_queue(),{ self.presentViewController(alert, animated: true, completion: nil) }) } ``` But I tried to do the same thing in objective C like so ``` - (void)alertMessage : (NSString*) message { UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Alert" message:message preferredStyle:UIAlertControllerStyleAlert]; UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:NULL]; [alert addAction:okAction]; [dispatch_async(dispatch_get_main_queue(), ^(void){ [self presentViewController:alert animated:true completion:NULL]; })]; } ``` I'm getting an error "expected identifier". What am I doing wrong?

Original source