解析目标-C到Swift iOS

Question

I am having trouble trying to change Objective - C code to Swift. This is with the Parse framework. If anyone knows how the following code should be written in Swift, it would help me a lot.

 [user signUpInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
    if (!error) {
        //The registration was successful, go to the wall
        [self performSegueWithIdentifier:@"SignupSuccesful" sender:self];

    }

Answer 1

[NSObject: Anyobject]? does not have a member named subscript parse compile error will be thrown.

The code should be like that because userInfor maybe be nil.

user.signUpInBackgroundWithBlock {
    (succeeded: Bool!, error: NSError!) -> Void in
    if !(error != nil) {
        // Hooray! Let them use the app now.
    } else {
        if let errorString = error.userInfo?["error"] as? NSString {
            println(errorString)
        }
    }
}

Answer 2

Parse happens to have an example of this exact method in their documentation. I think they'll be OK if I excerpt it here:

user.signUpInBackgroundWithBlock {
  (succeeded: Bool!, error: NSError!) -> Void in
  if !error {
    // Hooray! Let them use the app now.
  } else {
    let errorString = error.userInfo["error"] as NSString
    // Show the errorString somewhere and let the user try again.
  }
}

Answer 3

It would be something like this.

user.signUpInBackground {
    (success: Bool!, error: NSError!) -> Void in
    if !error {
        [unowned self] in
        self.performSegue("SignupSuccesful", sender:self);
}

Edit: Parse actually has Swift support. Here's a tutorial for it.

Edit2: You shouldn't refer to self inside a block. Use unowned self instead.