# 📚 Official Books **URL:** https://forums.kodeco.com/c/books/6.md?page=87 [Latest](https://forums.kodeco.com/latest.md) · [Categories](https://forums.kodeco.com/categories.md) · [Tags](https://forums.kodeco.com/tags.md) **Page:** 88 --- ## [Little issue with checklist](https://forums.kodeco.com/t/little-issue-with-checklist/80357)
**Author:** [@lac\_ekim](https://forums.kodeco.com/u/lac_ekim)\ **Replies:** 2\ **Last updated:** [August 30, 2019, 8:27pm UTC](https://forums.kodeco.com/t/little-issue-with-checklist/80357 "2019-08-30T20:27:35Z")
on checklist I’m running into a little issue. Basically I have everything working but it is making two instances rather then one when I hit done. I know its a bone headed move, sorry chapter 13 Checklist.zip (37.3 KB) --- ## [Chapter29 confusion about code](https://forums.kodeco.com/t/chapter29-confusion-about-code/78916)
**Author:** [@feanor](https://forums.kodeco.com/u/feanor)\ **Replies:** 1\ **Last updated:** [August 30, 2019, 7:00pm UTC](https://forums.kodeco.com/t/chapter29-confusion-about-code/78916 "2019-08-30T19:00:24Z")
On page 706, we have this line here: what is the : in showLocationDetails( \_: ) ? --- ## [Xcode is not installed](https://forums.kodeco.com/t/xcode-is-not-installed/69979)
**Author:** [@ibirdbluer](https://forums.kodeco.com/u/ibirdbluer)\ **Replies:** 5\ **Last updated:** [August 30, 2019, 6:57pm UTC](https://forums.kodeco.com/t/xcode-is-not-installed/69979 "2019-08-30T18:57:24Z")
My Xcode was downloaded from App Store, I can run other project ,Xcode version is 10.2.1, macOS version is 10.14.4, MacBook Pro (15-inch, 2018). when I run ./bootstrap.sh, the terminal shows “(!!) Xcode is not installed”… --- ## [Please suggest books for animation](https://forums.kodeco.com/t/please-suggest-books-for-animation/79717)
**Author:** [@thejigsaw](https://forums.kodeco.com/u/thejigsaw)\ **Replies:** 1\ **Last updated:** [August 29, 2019, 12:44am UTC](https://forums.kodeco.com/t/please-suggest-books-for-animation/79717 "2019-08-29T00:44:25Z")
I just start new Animation Studio in Mumbai & trying to establish my company so give me some suggestions or any book , tools that would help me. --- ## [How to send push notifications to a specific user?](https://forums.kodeco.com/t/how-to-send-push-notifications-to-a-specific-user/80122)
**Author:** [@sparklydust](https://forums.kodeco.com/u/sparklydust)\ **Replies:** 2\ **Last updated:** [August 27, 2019, 3:32pm UTC](https://forums.kodeco.com/t/how-to-send-push-notifications-to-a-specific-user/80122 "2019-08-27T15:32:12Z")
I have read the book but when it comes to use Vapor as a server side to handle push notifications, there is no explanation on how to send notifications to one user. What is the best way to save user device tokens, as it… --- ## [Removing delivered notifications](https://forums.kodeco.com/t/removing-delivered-notifications/62853)
**Author:** [@etjen123](https://forums.kodeco.com/u/etjen123)\ **Replies:** 5\ **Last updated:** [August 27, 2019, 2:25pm UTC](https://forums.kodeco.com/t/removing-delivered-notifications/62853 "2019-08-27T14:25:10Z")
Hi, Let me just say that the book indeed offers a deep dive into push notifications and related matters. I really liked it. There would be one topic that I would have like to read for example and that I had to deal with… --- ## [Best data layout in threadgroup memory](https://forums.kodeco.com/t/best-data-layout-in-threadgroup-memory/79663)
**Author:** [@octavo](https://forums.kodeco.com/u/octavo)\ **Replies:** 6\ **Last updated:** [August 26, 2019, 12:10am UTC](https://forums.kodeco.com/t/best-data-layout-in-threadgroup-memory/79663 "2019-08-26T00:10:54Z")
Is threadgroup memory in Metal similar to shared memory in CUDA? Is there a similar bank conflicts issue in Metal? I try to optimize the memory access in threadgroup memory. Thanks --- ## [Chapter 9: onPost() func and closure](https://forums.kodeco.com/t/chapter-9-onpost-func-and-closure/79779)
**Author:** [@mike](https://forums.kodeco.com/u/mike)\ **Replies:** 1\ **Last updated:** [August 25, 2019, 11:13pm UTC](https://forums.kodeco.com/t/chapter-9-onpost-func-and-closure/79779 "2019-08-25T23:13:03Z")
Hi, I don’t quite understand how the func post() is structured in Chapter 9. Can someone please explain how the “using” closure will be called in the viewDidLoaded() l later? “extension Notification.Name { // 1 stati… --- ## [Chapter 16 - particles pipelineState pixelFormat](https://forums.kodeco.com/t/chapter-16-particles-pipelinestate-pixelformat/79958)
**Author:** [@jplozach](https://forums.kodeco.com/u/jplozach)\ **Replies:** 2\ **Last updated:** [August 25, 2019, 1:17am UTC](https://forums.kodeco.com/t/chapter-16-particles-pipelinestate-pixelformat/79958 "2019-08-25T01:17:30Z")
Hello, I try to have particles as fire of chapter 16 in a 3D scene as the one of the chapter 9. So I have 3 pipelineState : rendererPipelineState for the 3D scene, particulePipelineState to compute the particles, pa… --- ## [Practical question on merging playground](https://forums.kodeco.com/t/practical-question-on-merging-playground/61592)
**Author:** [@nidupb](https://forums.kodeco.com/u/nidupb)\ **Replies:** 0\ **Last updated:** [February 7, 2019, 1:12am UTC](https://forums.kodeco.com/t/practical-question-on-merging-playground/61592 "2019-02-07T01:12:58Z")
Hi, I’m practicing swift apprentice in the same playground, but at a certain stage of the book/video, it is becoming useful to use the existing start playground that comes with the video. I’d like to import it within my… --- ## [Ch 4 - DebugLights](https://forums.kodeco.com/t/ch-4-debuglights/52907)
**Author:** [@12o1v](https://forums.kodeco.com/u/12o1v)\ **Replies:** 13\ **Last updated:** [August 24, 2019, 7:50am UTC](https://forums.kodeco.com/t/ch-4-debuglights/52907 "2019-08-24T07:50:18Z")
PDF Page 133 suggests using DebugLights.swift : “debugLights(renderEncoder: renderEncoder, lightType: Sunlight)” This didn’t work for me, and not knowing why, I spent time making sure I had followed the instructions. Wh… --- ## [Color Images in New Edition?](https://forums.kodeco.com/t/color-images-in-new-edition/79796)
**Author:** [@anon97552996](https://forums.kodeco.com/u/anon97552996)\ **Replies:** 3\ **Last updated:** [August 23, 2019, 12:53pm UTC](https://forums.kodeco.com/t/color-images-in-new-edition/79796 "2019-08-23T12:53:43Z")
I own the latest edition (7th) in PDF format and the third edition in hard-copy. My physical book does not have any images or text in color; it’s all black and white with a very small font that’s hard to read, especiall… --- ## [Chapter 1: Challenge 3 Animate the clouds](https://forums.kodeco.com/t/chapter-1-challenge-3-animate-the-clouds/79360)
**Author:** [@jayquinn](https://forums.kodeco.com/u/jayquinn)\ **Replies:** 2\ **Last updated:** [August 23, 2019, 11:57am UTC](https://forums.kodeco.com/t/chapter-1-challenge-3-animate-the-clouds/79360 "2019-08-23T11:57:06Z")
Hey guys! In this challenge everything is working perfect at first. The clouds were running good. But if I clicked home button and then came back. The positions of all the clouds were reset and started animation from the… --- ## [BullsEye Adding Extra Screen problem](https://forums.kodeco.com/t/bullseye-adding-extra-screen-problem/79565)
**Author:** [@sarahtexas2016](https://forums.kodeco.com/u/sarahtexas2016)\ **Replies:** 1\ **Last updated:** [August 22, 2019, 9:43pm UTC](https://forums.kodeco.com/t/bullseye-adding-extra-screen-problem/79565 "2019-08-22T21:43:28Z")
My app just crashed with the issues “Thread 1: signal SIGABRT”. What is that problem?. (When I clicked the Info button to go the About Screen. ) --- ## [ePub rendering issues](https://forums.kodeco.com/t/epub-rendering-issues/74212)
**Author:** [@abunur](https://forums.kodeco.com/u/abunur)\ **Replies:** 4\ **Last updated:** [August 22, 2019, 6:32pm UTC](https://forums.kodeco.com/t/epub-rendering-issues/74212 "2019-08-22T18:32:57Z")
seeing same issue as on some of the other ePubs, seems numbered lists can break down / numbering is not preserved. Might be an issue with Deckle, not sure. The above is the first code explanation in Chapter 2. --- ## [License Question](https://forums.kodeco.com/t/license-question/76790)
**Author:** [@weininger6](https://forums.kodeco.com/u/weininger6)\ **Replies:** 2\ **Last updated:** [August 22, 2019, 6:31pm UTC](https://forums.kodeco.com/t/license-question/76790 "2019-08-22T18:31:55Z")
Quick question about the book license. From this paragraph it sounds like I can’t use the game I build throughout the book as a base to build my own game then sell? Not looking to use the artwork I just want to use the b… --- ## [Missing Screen Capture Images](https://forums.kodeco.com/t/missing-screen-capture-images/76160)
**Author:** [@whitanderson](https://forums.kodeco.com/u/whitanderson)\ **Replies:** 2\ **Last updated:** [August 22, 2019, 6:28pm UTC](https://forums.kodeco.com/t/missing-screen-capture-images/76160 "2019-08-22T18:28:03Z")
I recently bought a print copy of iOS Apprentice, Seventh Edition, Beginning iOS development with Swift 4.2. At the bottom of page 61, the text indicates that there is a screen capture. My problem is that it isn’t there… --- ## [Environment variables keep disappearing, Chapter 25](https://forums.kodeco.com/t/environment-variables-keep-disappearing-chapter-25/79305)
**Author:** [@jjjeeerrr111](https://forums.kodeco.com/u/jjjeeerrr111)\ **Replies:** 3\ **Last updated:** [August 22, 2019, 5:57pm UTC](https://forums.kodeco.com/t/environment-variables-keep-disappearing-chapter-25/79305 "2019-08-22T17:57:34Z")
Everytime i run vapor xcode -y, the environment variables for github/google get wiped. Is this normal? How would this be handled in production. thanks --- ## [Compile error in Ch 9 Intermediate Physics](https://forums.kodeco.com/t/compile-error-in-ch-9-intermediate-physics/79446)
**Author:** [@abridge683](https://forums.kodeco.com/u/abridge683)\ **Replies:** 2\ **Last updated:** [August 22, 2019, 3:46pm UTC](https://forums.kodeco.com/t/compile-error-in-ch-9-intermediate-physics/79446 "2019-08-22T15:46:28Z")
I’m totally missing something here. I see someone else has had this, figured it out, and didn’t say what the problem was. Here’s the issue in Xcode: I’m not seeing where I’ve gone wrong and would appreciate a pointe… --- ## [Paper edition have horrible impression quality](https://forums.kodeco.com/t/paper-edition-have-horrible-impression-quality/76006)
**Author:** [@javierov](https://forums.kodeco.com/u/javierov)\ **Replies:** 2\ **Last updated:** [August 22, 2019, 1:08pm UTC](https://forums.kodeco.com/t/paper-edition-have-horrible-impression-quality/76006 "2019-08-22T13:08:58Z")
Hi. Last week I bought the paper edition of this book at amazon.com. Even though the content is very interesting, the quality of the impression is so poor, that it is impossible to see clearly the desciptive illustration… --- ## [Math Utilities - does multipication and division make sense?](https://forums.kodeco.com/t/math-utilities-does-multipication-and-division-make-sense/77740)
**Author:** [@abridge683](https://forums.kodeco.com/u/abridge683)\ **Replies:** 1\ **Last updated:** [August 22, 2019, 6:13am UTC](https://forums.kodeco.com/t/math-utilities-does-multipication-and-division-make-sense/77740 "2019-08-22T06:13:12Z")
In the math utilities there are operators defined for both mulitpicaion and division on CGPoint. Given these are being used as vector representation does it make sense to multiply the CGPoints and return another CGPoint… --- ## [Chapter 18: Tokens are never deleted](https://forums.kodeco.com/t/chapter-18-tokens-are-never-deleted/73036)
**Author:** [@bababoega](https://forums.kodeco.com/u/bababoega)\ **Replies:** 6\ **Last updated:** [August 22, 2019, 6:08am UTC](https://forums.kodeco.com/t/chapter-18-tokens-are-never-deleted/73036 "2019-08-22T06:08:36Z")
I was implementing token authentication as per chapter 18 of the book. But then I realized. The tokens get saved every time a user logs in, but are never deleted, or never expire. Wouldn’t loggin in again and again cause… --- ## [Animation in chapter 2, the challenge](https://forums.kodeco.com/t/animation-in-chapter-2-the-challenge/44416)
**Author:** [@crackerjack](https://forums.kodeco.com/u/crackerjack)\ **Replies:** 9\ **Last updated:** [August 22, 2019, 5:22am UTC](https://forums.kodeco.com/t/animation-in-chapter-2-the-challenge/44416 "2019-08-22T05:22:29Z")
An answer is given in chapter 3 for how the earth, and the moon are animated - “scene.isPaused = false” but I find no such code the challenge source! --- ## [SceneKit Book - Important question to the authors](https://forums.kodeco.com/t/scenekit-book-important-question-to-the-authors/77827)
**Author:** [@danieleciti](https://forums.kodeco.com/u/danieleciti)\ **Replies:** 1\ **Last updated:** [August 22, 2019, 5:20am UTC](https://forums.kodeco.com/t/scenekit-book-important-question-to-the-authors/77827 "2019-08-22T05:20:51Z")
Hello, I bought your SceneKit book and I’ve found it very interesting! I have a small question about the chapter 19 - Transitions. In this chapter you use an SKTransition object to switch between 2 scn scenes, and you us… --- ## [Errata: Chapter 13 closing paragraph](https://forums.kodeco.com/t/errata-chapter-13-closing-paragraph/77080)
**Author:** [@perryao](https://forums.kodeco.com/u/perryao)\ **Replies:** 1\ **Last updated:** [August 22, 2019, 3:58am UTC](https://forums.kodeco.com/t/errata-chapter-13-closing-paragraph/77080 "2019-08-22T03:58:19Z")
Chapter 12 ends with the following paragraph: “In the next chapter, you will learn how to further improve your code by integrating the Data Binding library to bind your UI components in your layouts to your data sources… --- ## [FillColor meets FillTexture: Changing color of named child](https://forums.kodeco.com/t/fillcolor-meets-filltexture-changing-color-of-named-child/76789)
**Author:** [@justinjngan](https://forums.kodeco.com/u/justinjngan)\ **Replies:** 3\ **Last updated:** [August 22, 2019, 3:19am UTC](https://forums.kodeco.com/t/fillcolor-meets-filltexture-changing-color-of-named-child/76789 "2019-08-22T03:19:32Z")
In the final challenge of Chapter 11, in which we are asked to change the fill color and see it blend with the Texture, I find that when I do this, the arrow’s texture does indeed blend with the Texture background. Howev… --- ## [Code correction: discoball interaction](https://forums.kodeco.com/t/code-correction-discoball-interaction/76774)
**Author:** [@justinjngan](https://forums.kodeco.com/u/justinjngan)\ **Replies:** 1\ **Last updated:** [August 22, 2019, 3:18am UTC](https://forums.kodeco.com/t/code-correction-discoball-interaction/76774 "2019-08-22T03:18:19Z")
In 2D Apple Games, pg 305, the handler for interact() only addresses the case where the gamestate, isDiscoTime is false. It does not address when isDiscoTime is true. As a result, you can start the disco movie animation… --- ## [Gameplaykit - Randomness](https://forums.kodeco.com/t/gameplaykit-randomness/77075)
**Author:** [@praxon48](https://forums.kodeco.com/u/praxon48)\ **Replies:** 1\ **Last updated:** [August 22, 2019, 2:08am UTC](https://forums.kodeco.com/t/gameplaykit-randomness/77075 "2019-08-22T02:08:39Z")
Does any body knows if Gameplaykit can generate “truly random numbers”, not pseudo random numbers? Thank you in advance for any information. --- ## [Chapter 6: Starter project is incorrect](https://forums.kodeco.com/t/chapter-6-starter-project-is-incorrect/75978)
**Author:** [@duckmole](https://forums.kodeco.com/u/duckmole)\ **Replies:** 1\ **Last updated:** [August 22, 2019, 1:26am UTC](https://forums.kodeco.com/t/chapter-6-starter-project-is-incorrect/75978 "2019-08-22T01:26:32Z")
Hi guys, I found that the starter project of chapter 6 is incorrect, it seems like the starter project for chapter 5.:sweat\_smile: --- ## [Chapter 20 init](https://forums.kodeco.com/t/chapter-20-init/62834)
**Author:** [@feanor](https://forums.kodeco.com/u/feanor)\ **Replies:** 5\ **Last updated:** [August 22, 2019, 12:05am UTC](https://forums.kodeco.com/t/chapter-20-init/62834 "2019-08-22T00:05:24Z")
In chapter 20, we use override init in the ChecklistItem.swift, but in Checklist.swift, we use init. What is the difference then? [Previous page](https://forums.kodeco.com/c/books/6.md?page=86) [Next page](https://forums.kodeco.com/c/books/6.md?page=88)