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iOS

Posted by Derek Medlin
Derek Medlin
6,151 Points

Ribbit Code Challenge - Signing Up New Users Part 2 : Task 1 of 4

TASK: "In our view controller below we want to sign up new users for our app. In the signup method, start by capturing the username and password from two UITextField properties: 'usernameField' and 'passwordField'. Store the values in the properties 'username' and 'password'."

MY CODE:

        #import "SignupViewController.h"
        #import <Parse/Parse.h>

    @implementation SignupViewController

    - (IBAction)signup:(id)sender {
        NSString *username = self.usernameField.text;
        NSString *password = self.passwordField.text;
    }

    @end

ALSO TRIED (incase he was just testing us): 

            #import "SignupViewController.h"
        #import <Parse/Parse.h>

    @implementation SignupViewController

    - (IBAction)signup:(id)sender {
        NSString *username = [self.usernameField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
        NSString *password = [self.passwordField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
    }

    @end

I know it must be something small that I'm missing but I've redone it several times and I can't seem to find what is wrong. This should be easy lol.

9 Answers

Ben Jakuben
STAFF
Ben Jakuben
Treehouse Teacher
Ben Jakuben
Ben Jakuben
Treehouse Teacher

Ah, I just realized what is wrong here. username and password are properties of the view controller, so you need to set them that way, not declare them as new NSString variables.

Derek Medlin
Derek Medlin
6,151 Points

Oh sorry, I never put my actual problem (it was early lol). I tried both of the above code and it fails. Am I missing something? Because I would almost bet money it's right or I'm just blind. Sorry for not being clear.

Derek Medlin
Derek Medlin
6,151 Points

Sorry I see you've updated your answer. I replied from email which had your original post. Ok thanks.

Masao Kitamura
Masao Kitamura
1,783 Points

Ben - why is this different than the tutorial? In the tutorial, you don't make username and password properties of the view controller (ie. you don't need "self" like you do in the code challenge). Which is more correct?

Ben Jakuben
Ben Jakuben
Treehouse Teacher
Ben Jakuben
Ben Jakuben
Treehouse Teacher

Well, the reason here actually has to do with the internals of our Code Challenge engine. We can check properties in ways that we can't check local variables, which is how it is in the actual app. :)

Also, I like to make the code challenges slightly different than the actual code for a few reasons:

  1. You get to practice the concepts a little differently, which is always good.
  2. It's somewhat representative of working with someone else's code, which we do quite often as developers. You can't always change what others have written.
  3. There may be reasons for doing things other ways. Like in this example, perhaps it makes sense to store the username and password as properties for use in multiple methods.

Anyhow - I hope it doesn't cause too much confusion. I'm certainly open to feedback about the code challenges, so if it's causing too much trouble I'll look for a way to improve them. :)

Masao Kitamura
Masao Kitamura
1,783 Points

I agree with your points, and the code challenges are definitely very helpful.

However, it would be nice if there was a "show answer" option, to handle the cases when the student has exhausted all their attempted answers.

Otherwise, for me, I just copy/paste the question into Google and pray! :) (and if this fails, I would have learned more from just seeing the answer, rather than skipping the question all together)

Ben Jakuben
Ben Jakuben
Treehouse Teacher
Ben Jakuben
Ben Jakuben
Treehouse Teacher

We've discussed the merits of providing answers. If you email help@teamtreehouse.com you can ask for an answer. But we want to avoid that as much as possible to make passing the code challenges mean something more than just Googling the answer. And we want students to post problems in here so that everyone can help each other, because in the discussion and extended teaching everyone really cements their learning. :smile:

We do need to take feedback about the challenges into account and adjust as necessary. We have also talked about adding hints that increase in helpfulness, but that's just a lower priority at the moment.

Derek Medlin
Derek Medlin
6,151 Points

I think it's great how it is now, I just made a stupid mistake that and it blows my mind that I didn't see it. It clearly said PROPERTY and i read right through it, not paying attention because I was cramming. You learn the most from mistakes and this code challenge, IMO, was clear enough. I just kept missing it because I had that "temporary blindness" that we all get from time to time.Thanks again for the amazing tutorials.

Paul Cisneros
Paul Cisneros
1,332 Points

So...?

UIViewController *username = self.usernameField.text; UIViewController *password = self.passwordField.text;

This one's pretty hard to crack.

Ben Jakuben
Ben Jakuben
Treehouse Teacher
Ben Jakuben
Ben Jakuben
Treehouse Teacher

Derek gave you a good response below. In your code you are creating two new variables (username and password) that are UIViewControllers. These properties are already defined in the current view controller and can be accessed using self, just like you are accessing the usernameField and passwordField properties.

onurtekin
onurtekin
7,346 Points

How do we know that username and password are properties of view controller? Where are they defined exactly?

Chris Bull
Chris Bull
56 Points
Chris Bull
Chris Bull
56 Points

For anyone who still gets stuck on this, and doesn't understand what the comments above mean, here is the answer: self.username = self.usernameField.text; self.password = self.passwordField.text;

Luke Schoen
Luke Schoen
3,317 Points
Luke Schoen
Luke Schoen
3,317 Points

Thanks for the feedback in this post. I was really struggling to work this one out. I agree with Ben in that providing hints and answers in the actual challenges destroys the value of the challenge and prior achievements altogether. The challenges and points system motivates me to perform my own research through the documentation. I try different approaches to solve the problem, and in the process I consolidate my learning. When my options are exhausted I search the internet and Teamtreehouse.com forums, creating my own new discussion as a last resort.

Derek Medlin
Derek Medlin
6,151 Points

Yeah this site is great and I agree with Ben as well. We don't need answers spoon fed to us, if we can't think for ourselves then how are we going to be able to design an app in the first place.

robert cioffi
robert cioffi
3,466 Points
robert cioffi
robert cioffi
3,466 Points

Whats the difference between saying this:

   self.username = self.usernameField.text;
   self.password = self.passwordField.text;

and

   username = [self.usernameField.text self];
   password = [self.passwordField.text self];

I'm a little confused to what the self value does in some of the various ways we've written code

Ben Jakuben
Ben Jakuben
Treehouse Teacher
Ben Jakuben
Ben Jakuben
Treehouse Teacher

This has to do with "variable scope," which defines how and when the variables will be available. As properties of the class, variables are available anywhere in the class. The self keyword refers to the current instance of a class, so we use it to reference class properties and methods. Without self, then the variable must be declared locally somewhere in the implementation file. It could be a local variable that lives within the current method, a parameter that's passed into it, or perhaps a global variable in the implementation file that's available anywhere within the file.

The takeaway here is that we use self any time we need to reference something for the class that is declared in its header file. In this code challenge, username and password are already declared in the header file as properties of this class.

J Kim
J Kim
15,218 Points
J Kim
J Kim
15,218 Points

I understand different contexts give us larger scope of understanding. However, I do think clear instructions would not have hurt. When things don't seem too purposeful and vague I think it could become rather misleading. Just my two cents..

Derek Saunders
Derek Saunders
5,167 Points
Derek Saunders
Derek Saunders
5,167 Points

Paul almost, instead of using UIViewController remember to use self.

Dan Boyle
Dan Boyle
2,978 Points
Dan Boyle
Dan Boyle
2,978 Points

I'm a little confused as well with this challenge. It's my understanding that you create the UITextField properties to capture the data entered by the user. Those are stored in usernameField and passwordField.

Why would you create two more properties called username and password?

Would those look like this?

@property (nonatomic, weak) NSString *username; @property (nonatomic, weak) NSString *password;

Or am I just going way off course here?

Ben Jakuben
Ben Jakuben
Treehouse Teacher
Ben Jakuben
Ben Jakuben
Treehouse Teacher

The properties are already created for you in this challenge. You simply need to set them from the UITextField properties.

Benjamin McMahan
Benjamin McMahan
6,679 Points

I really think it would have been helpful to explain this one a bit better and include the header file for SignupViewController. If that were available, as it would be in the development environment, the challenge would have made a lot more sense. I think most of us were attempting exactly what the original poster detailed - NSString *username = self.usernameField.text;

Dan Boyle
Dan Boyle
2,978 Points
Dan Boyle
Dan Boyle
2,978 Points

Hi Ben... I got through the code challenge. I was just curious... is that how you would set them. And if so, why would you want to do it that way if you've already create UITextField properties for usernameField and passwordField?

Any benefit?

Ben Jakuben
Ben Jakuben
Treehouse Teacher
Ben Jakuben
Ben Jakuben
Treehouse Teacher

Good question. For convenience, really. You need the IBOutlet properties, but the NSString ones are for convenience. If you are using the values from the UITextFields in different places then creating properties can be more convenient than getting the values each time. You could accomplish the same thing with local variables, but it would just depend on how and where they are being used.

Part of the reason we used properties in this challenge is to make testing easier on our part since we can access the properties from our validation engine. :)

oscar gonzalez
oscar gonzalez
7,072 Points
oscar gonzalez
oscar gonzalez
7,072 Points

My answer its great that Ben improve us to do our best in this challenge in my opinion im very new in this world of IOS and this helo me a lot to learn more Ben always make stack LOL because sometimes i dont have the best answer for his challenge but for this quiz the answer is this

self.username = self.usernameField.text; self.password = self.passwordField.text;