# iOS Apprentice **URL:** https://forums.kodeco.com/c/books/ios-apprentice/7.md [Latest](https://forums.kodeco.com/latest.md) · [Categories](https://forums.kodeco.com/categories.md) · [Tags](https://forums.kodeco.com/tags.md) --- ## [Errata for iOS Apprentice v4.1](https://forums.kodeco.com/t/errata-for-ios-apprentice-v4-1/43)
**Author:** [@rwenderlich](https://forums.kodeco.com/u/rwenderlich)\ **Replies:** 22\ **Last updated:** [March 16, 2021, 10:07pm UTC](https://forums.kodeco.com/t/errata-for-ios-apprentice-v4-1/43 "2021-03-16T22:07:20Z")
This topic is for bugs, typos, and other mistakes in iOS Apprentice v4.1. --- ## [About the iOS Apprentice category](https://forums.kodeco.com/t/about-the-ios-apprentice-category/21)
**Author:** [@rwenderlich](https://forums.kodeco.com/u/rwenderlich)\ **Replies:** 20\ **Last updated:** [November 7, 2021, 8:39pm UTC](https://forums.kodeco.com/t/about-the-ios-apprentice-category/21 "2021-11-07T20:39:21Z")
These are the official forums for the iOS Apprentice, our book on beginning iOS development. This is the place to ask any questions you may have about the book. We hope you enjoy the book! :\] --- ## [Chapter 13 extension code explanation](https://forums.kodeco.com/t/chapter-13-extension-code-explanation/211851)
**Author:** [@emma24](https://forums.kodeco.com/u/emma24)\ **Replies:** 1\ **Last updated:** [August 14, 2025, 6:40pm UTC](https://forums.kodeco.com/t/chapter-13-extension-code-explanation/211851 "2025-08-14T18:40:12Z")
in Chapter 13, the extension code works well after I imported to my project. It would be great if there is explanation of the code in the book. Those code are beyond a beginner level. Thank you. --- ## [Notebook highlights in book](https://forums.kodeco.com/t/notebook-highlights-in-book/201740)
**Author:** [@d\_evergreen](https://forums.kodeco.com/u/d_evergreen)\ **Replies:** 4\ **Last updated:** [January 30, 2024, 6:42pm UTC](https://forums.kodeco.com/t/notebook-highlights-in-book/201740 "2024-01-30T18:42:21Z")
Hi! I can see you have the feature to highlight some notes from the book. But it’s not working for me on Mac. It’s just giving me usual right-click options. Could you please advise? I’d really like to use this tool while… --- ## [How to download from GitHub - MacOS Apprentice](https://forums.kodeco.com/t/how-to-download-from-github-macos-apprentice/190389)
**Author:** [@paulmorecambe](https://forums.kodeco.com/u/paulmorecambe)\ **Replies:** 3\ **Last updated:** [August 15, 2023, 10:07am UTC](https://forums.kodeco.com/t/how-to-download-from-github-macos-apprentice/190389 "2023-08-15T10:07:47Z")
I fail to be able to download the Snowman images as instructed in CH 5. I am a beginner and don’t understand GitHub. I try to drag Snowman folder to Assets as instructed but get no + sign as shown. I have been doing wel… --- ## [What is Chunk count in Modern Concurrency Unit 3?](https://forums.kodeco.com/t/what-is-chunk-count-in-modern-concurrency-unit-3/188853)
**Author:** [@anthony\_tran](https://forums.kodeco.com/u/anthony_tran)\ **Replies:** 0\ **Last updated:** [June 30, 2023, 8:31am UTC](https://forums.kodeco.com/t/what-is-chunk-count-in-modern-concurrency-unit-3/188853 "2023-06-30T08:31:10Z")
Hello, iOS champions! In the struct ByteAccumulator, What is chunk count? is that a block unit of bytes? why its value is the size of the file divided by 20? why 20? struct ByteAccumulator: CustomStringConvertible { … --- ## [Auto Layout Confusion](https://forums.kodeco.com/t/auto-layout-confusion/179330)
**Author:** [@iosnoob101](https://forums.kodeco.com/u/iosnoob101)\ **Replies:** 1\ **Last updated:** [October 12, 2022, 6:22pm UTC](https://forums.kodeco.com/t/auto-layout-confusion/179330 "2022-10-12T18:22:12Z")
Hello throughout the book it mentions to use constraints to auto layout the text field or various modules but im confused what you mean. How are we supposed to know the numbers for the margins and the book mentioned if w… --- ## [Tutorial 3 - MyLocations. Fatal Error and Hud](https://forums.kodeco.com/t/tutorial-3-mylocations-fatal-error-and-hud/15352)
**Author:** [@ricarami](https://forums.kodeco.com/u/ricarami)\ **Replies:** 6\ **Last updated:** [August 22, 2022, 9:00am UTC](https://forums.kodeco.com/t/tutorial-3-mylocations-fatal-error-and-hud/15352 "2022-08-22T09:00:58Z")
(SP) Que tal Matthijs, Lo primero que me quiero comentarle es que su ejercicio es fantástico, es de esas cosas que generan adicción, lo tuve ahí olvidado por muchos meses y ahora que he decidido dedicarle tiempo, me ti… --- ## [A question about optionals](https://forums.kodeco.com/t/a-question-about-optionals/172560)
**Author:** [@macteef](https://forums.kodeco.com/u/macteef)\ **Replies:** 2\ **Last updated:** [June 5, 2022, 3:21pm UTC](https://forums.kodeco.com/t/a-question-about-optionals/172560 "2022-06-05T15:21:27Z")
Consider this , let value = true print(value) —this will print true But I can also do this, print(true) it will print true. This is not the case with optionals. eg, let value: Int? = nil print(value) —this will pr… --- ## [Handle reverse geocoding errors, page 575](https://forums.kodeco.com/t/handle-reverse-geocoding-errors-page-575/166530)
**Author:** [@herm57](https://forums.kodeco.com/u/herm57)\ **Replies:** 0\ **Last updated:** [March 11, 2022, 7:53pm UTC](https://forums.kodeco.com/t/handle-reverse-geocoding-errors-page-575/166530 "2022-03-11T19:53:00Z")
Not sure where in the code this is suppose to be placed. I think it belongs in updateLabels() ➤ Replace the contents of the geocoding closure with the following: self.lastGeocodingError = error if error == nil, let pl… --- ## [Edit existing items](https://forums.kodeco.com/t/edit-existing-items/165048)
**Author:** [@ahmednagy](https://forums.kodeco.com/u/ahmednagy)\ **Replies:** 1\ **Last updated:** [February 21, 2022, 10:46am UTC](https://forums.kodeco.com/t/edit-existing-items/165048 "2022-02-21T10:46:52Z")
I’m working in the edit items chapter and i’ve been struggling with this code how the method firstIndex(of:) can find the item that i passed back didn’t i change it’s text? what is it comparing to exactly? it should be l… --- ## [Check if a UITextField is empty](https://forums.kodeco.com/t/check-if-a-uitextfield-is-empty/164780)
**Author:** [@ahmednagy](https://forums.kodeco.com/u/ahmednagy)\ **Replies:** 2\ **Last updated:** [February 19, 2022, 10:31pm UTC](https://forums.kodeco.com/t/check-if-a-uitextfield-is-empty/164780 "2022-02-19T22:31:09Z")
Can someone please explain this code a little bit in more details? I don’t understand how the range and replaceCharachters method work here, when we get the oldText and get the range in this text isn’t it supposed to be… --- ## [Find Core Animation book](https://forums.kodeco.com/t/find-core-animation-book/158364)
**Author:** [@lamln](https://forums.kodeco.com/u/lamln)\ **Replies:** 0\ **Last updated:** [November 23, 2021, 3:04pm UTC](https://forums.kodeco.com/t/find-core-animation-book/158364 "2021-11-23T15:04:35Z")
Hi everyone, I’m looking for this book iOS\_Core\_Animation\_Advanced\_Techniques. Anyone have this book? Thank you in advance for your attention to this matter. --- ## [\### What is the procedure to develop web AR apps?](https://forums.kodeco.com/t/what-is-the-procedure-to-develop-web-ar-apps/157710)
**Author:** [@alice7890](https://forums.kodeco.com/u/alice7890)\ **Replies:** 0\ **Last updated:** [November 17, 2021, 9:34am UTC](https://forums.kodeco.com/t/what-is-the-procedure-to-develop-web-ar-apps/157710 "2021-11-17T09:34:27Z")
WebAR apps can be developed using an AR creation platform where solutions can be developed hassle-free. For that one has to decide what projects they want to build upon and what effective strategies they can use to popul… --- ## [How to obtain the iPad system version macro definition identifier](https://forums.kodeco.com/t/how-to-obtain-the-ipad-system-version-macro-definition-identifier/156559)
**Author:** [@richmond\_jam](https://forums.kodeco.com/u/richmond_jam)\ **Replies:** 0\ **Last updated:** [November 10, 2021, 6:42am UTC](https://forums.kodeco.com/t/how-to-obtain-the-ipad-system-version-macro-definition-identifier/156559 "2021-11-10T06:42:33Z")
This week I need to finish logic for iPad. I want to obtain the iPad system version macro definition identifier. For example, we always use “\_\_IPHONE\_OS\_VERSION\_MAX\_ALLOWED \> \_\_IPHONE\_12\_0” in iOS for iPhone. But now I w… --- ## [iOS Apprentice My Locations app PhotoID issue](https://forums.kodeco.com/t/ios-apprentice-my-locations-app-photoid-issue/155135)
**Author:** [@titkonen](https://forums.kodeco.com/u/titkonen)\ **Replies:** 0\ **Last updated:** [October 28, 2021, 5:49am UTC](https://forums.kodeco.com/t/ios-apprentice-my-locations-app-photoid-issue/155135 "2021-10-28T05:49:36Z")
Hi there! I am learning Swift coding and did MyLocations iOS app demo from book. I now try to expand it in same app to learn more how to play with CoreData. I am now facing the issue when I am trying to save images. Whe… --- ## [Chapter 32: Search Bar Height](https://forums.kodeco.com/t/chapter-32-search-bar-height/154755)
**Author:** [@sebaferreras](https://forums.kodeco.com/u/sebaferreras)\ **Replies:** 0\ **Last updated:** [October 25, 2021, 5:13pm UTC](https://forums.kodeco.com/t/chapter-32-search-bar-height/154755 "2021-10-25T17:13:13Z")
Hello! This is probably a very silly question but anyways… When selecting the search bar in the StoryBoard, the height shown is 51 points (this is also the value used when setting the tableView contentInset tableView.… --- ## [Book Update with update technology](https://forums.kodeco.com/t/book-update-with-update-technology/146627)
**Author:** [@jinkazama](https://forums.kodeco.com/u/jinkazama)\ **Replies:** 0\ **Last updated:** [August 21, 2021, 9:53pm UTC](https://forums.kodeco.com/t/book-update-with-update-technology/146627 "2021-08-21T21:53:34Z")
First of all, I would like to say that, Raywenderlich’s books are good books and excellent books. With PDF format, they look pretty and attractive and basically for iOS and android developments, besides languages used, b… --- ## [iOS Apprentice 8th Ed: Errata - Various Chapters](https://forums.kodeco.com/t/ios-apprentice-8th-ed-errata-various-chapters/91047)
**Author:** [@jamesh](https://forums.kodeco.com/u/jamesh)\ **Replies:** 19\ **Last updated:** [August 16, 2021, 12:59pm UTC](https://forums.kodeco.com/t/ios-apprentice-8th-ed-errata-various-chapters/91047 "2021-08-16T12:59:21Z")
Hi there, hope this is the right category for this… Went thru the first 8 chapters and they were really great and helpful… Found a bug in chapter 7 that stopped me dead in my tracks and made me go to the Final Code file… --- ## [Checklist app - Auto Correction makes possible empty title](https://forums.kodeco.com/t/checklist-app-auto-correction-makes-possible-empty-title/119319)
**Author:** [@ericlm](https://forums.kodeco.com/u/ericlm)\ **Replies:** 1\ **Last updated:** [April 9, 2021, 7:34pm UTC](https://forums.kodeco.com/t/checklist-app-auto-correction-makes-possible-empty-title/119319 "2021-04-09T19:34:56Z")
Hi, I’m working on the Checklist App, and I discovered a bug that I don’t really know how to fix. It happens when you’re typing the name of your item (or list) and have the clear button enabled. If what you’re currently … --- ## [Putting Row Data into Cells](https://forums.kodeco.com/t/putting-row-data-into-cells/111847)
**Author:** [@mippster](https://forums.kodeco.com/u/mippster)\ **Replies:** 6\ **Last updated:** [April 9, 2021, 6:58pm UTC](https://forums.kodeco.com/t/putting-row-data-into-cells/111847 "2021-04-09T18:58:24Z")
Hello, I am new to coding, so sorry if this is obvious… I am in iOS Apprentice, Section 2. I just learned to set the Tag field in the Attributes inspector to 1000. The next line in the book, says: bordered width = 30… --- ## [Chapter 8 (ePub v8.3.0)](https://forums.kodeco.com/t/chapter-8-epub-v8-3-0/118853)
**Author:** [@geezer](https://forums.kodeco.com/u/geezer)\ **Replies:** 1\ **Last updated:** [April 9, 2021, 2:33pm UTC](https://forums.kodeco.com/t/chapter-8-epub-v8-3-0/118853 "2021-04-09T14:33:10Z")
Beginner here and just looking for some assistance on a few things: Did anyone do the exercise on page 357, having controls resize base on different iPhones? Just looking for guidance. The Crossfade code is not wor… --- ## [Chapter 12: UITextFieldDelegate vs event handler?](https://forums.kodeco.com/t/chapter-12-uitextfielddelegate-vs-event-handler/117575)
**Author:** [@steveca](https://forums.kodeco.com/u/steveca)\ **Replies:** 1\ **Last updated:** [April 8, 2021, 1:09am UTC](https://forums.kodeco.com/t/chapter-12-uitextfielddelegate-vs-event-handler/117575 "2021-04-08T01:09:05Z")
Hi all, I am working through the iOS apprentice book and learning a lot, so thanks! In chapter 12 something surprised me - in the “Add Event” view controller we implement methods of UITExtFieldDelegate to handle change… --- ## [Debugging section on Ch. 33](https://forums.kodeco.com/t/debugging-section-on-ch-33/117019)
**Author:** [@spacenikki](https://forums.kodeco.com/u/spacenikki)\ **Replies:** 1\ **Last updated:** [April 7, 2021, 12:00am UTC](https://forums.kodeco.com/t/debugging-section-on-ch-33/117019 "2021-04-07T00:00:21Z")
Not the same display as the material. Can someone please guide me on how I can view what exactly the material screenshot shows? Material says, after adding exception breakpoint to the app, I should see this: But I on… --- ## [Chapter 2: View as iPhone 8](https://forums.kodeco.com/t/chapter-2-view-as-iphone-8/116826)
**Author:** [@mcdanieljk8](https://forums.kodeco.com/u/mcdanieljk8)\ **Replies:** 3\ **Last updated:** [April 6, 2021, 4:49am UTC](https://forums.kodeco.com/t/chapter-2-view-as-iphone-8/116826 "2021-04-06T04:49:16Z")
Xcode 11.4.1 no longer has iPhone 8 as a “View as” option. iPhone SE (2nd Generation) is the same screen size. --- ## [How to get the Device Capacity from the plist](https://forums.kodeco.com/t/how-to-get-the-device-capacity-from-the-plist/116543)
**Author:** [@anilverma087](https://forums.kodeco.com/u/anilverma087)\ **Replies:** 1\ **Last updated:** [April 6, 2021, 2:41am UTC](https://forums.kodeco.com/t/how-to-get-the-device-capacity-from-the-plist/116543 "2021-04-06T02:41:15Z")
iOS Device Enrollment with Self-Developed MDM? UDID IMEI ICCID VERSION PRODUCT same for DeviceCapacity but its not working --- ## [Chapter 36: Table View Section Header Color](https://forums.kodeco.com/t/chapter-36-table-view-section-header-color/104926)
**Author:** [@clarkesm](https://forums.kodeco.com/u/clarkesm)\ **Replies:** 3\ **Last updated:** [April 4, 2021, 6:54am UTC](https://forums.kodeco.com/t/chapter-36-table-view-section-header-color/104926 "2021-04-04T06:54:47Z")
I’m working on the “Back to Black” section in chapter 36. I made all of the suggested changes to the table view, but I’m not able to get the section headers in the Locations table view to match the image shown in the bo… --- ## [UIKit, unwanted SceneDelegate, can't reference window in AppDelegate](https://forums.kodeco.com/t/uikit-unwanted-scenedelegate-cant-reference-window-in-appdelegate/113682)
**Author:** [@doyle](https://forums.kodeco.com/u/doyle)\ **Replies:** 2\ **Last updated:** [March 19, 2021, 12:35pm UTC](https://forums.kodeco.com/t/uikit-unwanted-scenedelegate-cant-reference-window-in-appdelegate/113682 "2021-03-19T12:35:27Z")
Using iOS\_Apprentice\_v7.0 to follow along with UIKit as I’m not currently a fan of SwiftUI. Got Stuck with Xcode 11.4.1 which auto generates the split AppDelegate and SceneDelegates. Trying to reference window in AppDe… --- ## [Chapter 10, Challenge 3, question on Structs](https://forums.kodeco.com/t/chapter-10-challenge-3-question-on-structs/131493)
**Author:** [@jimkardach](https://forums.kodeco.com/u/jimkardach)\ **Replies:** 2\ **Last updated:** [January 31, 2021, 6:01pm UTC](https://forums.kodeco.com/t/chapter-10-challenge-3-question-on-structs/131493 "2021-01-31T18:01:32Z")
Hi, I have been working on Chapter 10, challenge 3 and am stuck. While I’ve looked at the solution, my approach is slightly different and I’m trying to understand what is happening. // Battleship = write the game engi… --- ## [Not seeing iOS Apprentice in my products list](https://forums.kodeco.com/t/not-seeing-ios-apprentice-in-my-products-list/129682)
**Author:** [@steveb\_la](https://forums.kodeco.com/u/steveb_la)\ **Replies:** 4\ **Last updated:** [January 12, 2021, 5:28pm UTC](https://forums.kodeco.com/t/not-seeing-ios-apprentice-in-my-products-list/129682 "2021-01-12T17:28:56Z")
Is this book still being supported? I’m not seeing it in my purchased Products list. (I will post this in the General Discussions forum also) [Next page](https://forums.kodeco.com/c/books/ios-apprentice/7.md?page=1)