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Day 29

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Day 29 관련

100 Days of Swift - Day 29
Project 5, part three

Project 5, part three

I hope that today you inched a little closer to understanding closures, and that you’re starting to see that they are really just a very special kind of function. Sure they have weird syntax, and yes the capturing thing makes them behave in all sorts of interesting ways, but ultimately they are just anonymous functions that you pass around as if they were data.

If you’re still not sure about closures, it’s OK: we’ll be using them again and again, and sooner or later they’ll click. You’d do well to remember the words of Patrick McKenzie: “every great developer you know got there by solving problems they were unqualified to solve until they actually did it.”

Anyway, you have another project under your belt, and I hope you feel happy with everything you learned. Of course, now it’s time to solidify your knowledge with a test and some fresh challenges – you need to go beyond just following along with me, otherwise you’ll have a hard time remembering anything in the long term.

Today you should work through the wrap up chapter for project 5, complete its review, then work through all three of its challenges. As you’ll see, there is also a bonus challenge today – you need to be a bug detective!

Wrap up

Wrap up
100 Days of Swift - Day 29 - Wrap up
Wrap up

You've made it this far, so your Swift learning really is starting to come together, and I hope this project has shown you that you can make some pretty advanced things with your knowledge.

In this project, you learned a little bit more about UITableView: how to reload their data and how to insert rows. You also learned how to add text fields to UIAlertController so that you can accept user input. But you also learned some serious core stuff: more about Swift strings, closures, NSRange, and more. These are things you're going to use in dozens of projects over your Swift coding career, and things we'll be returning to again and again in this series.

Review what you learned

Anyone can sit through a tutorial, but it takes actual work to remember what was taught. It’s my job to make sure you take as much from these tutorials as possible, so I’ve prepared a short review to help you check your learning.

Click here to review what you learned in project 5.open in new window

Challenge

One of the best ways to learn is to write your own code as often as possible, so here are three ways you should try extending this app to make sure you fully understand what’s going on:

  1. Disallow answers that are shorter than three letters or are just our start word. For the three-letter check, the easiest thing to do is put a check into isReal() that returns false if the word length is under three letters. For the second part, just compare the start word against their input word and return false if they are the same.
  2. Refactor all the else statements we just added so that they call a new method called showErrorMessage(). This should accept an error message and a title, and do all the UIAlertController work from there.
  3. Add a left bar button item that calls startGame(), so users can restart with a new word whenever they want to.

Bonus: Once you’ve done those three, there’s a really subtle bug in our game and I’d like you to try finding and fixing it.

To trigger the bug, look for a three-letter word in your starting word, and enter it with an uppercase letter. Once it appears in the table, try entering it again all lowercase – you’ll see it gets entered. Can you figure out what causes this and how to fix it?

Hints

It is vital to your learning that you try the challenges above yourself, and not just for a handful of minutes before you give up.

Every time you try something wrong, you learn that it’s wrong and you’ll remember that it’s wrong. By the time you find the correct solution, you’ll remember it much more thoroughly, while also remembering a lot of the wrong turns you took.

This is what I mean by “there is no learning without struggle”: if something comes easily to you, it can go just as easily. But when you have to really mentally fight for something, it will stick much longer.

But if you’ve already worked hard at the challenges above and are still struggling to implement them, I’m going to write some hints below that should guide you to the correct answer.

If you ignore me and read these hints without having spent at least 30 minutes trying the challenges above, the only person you’re cheating is yourself.

Still here? OK. If you’re stuck on the bug finding bonus challenge, take a look at this line of code:

usedWords.insert(answer, at: 0)

Is that what it should be?

Wrap up - Additional

Once you’re done, tell other people: you’ve built your second game for iOS, and you’ve learned more about table views, alert controllers, and more.

You should be proud of what you’ve accomplished – keep going!