# 📚 Official Books **URL:** https://forums.kodeco.com/c/books/6.md?page=30 [Latest](https://forums.kodeco.com/latest.md) · [Categories](https://forums.kodeco.com/categories.md) · [Tags](https://forums.kodeco.com/tags.md) **Page:** 31 --- ## [Chapter 7 Errata](https://forums.kodeco.com/t/chapter-7-errata/50743)
**Author:** [@abunur](https://forums.kodeco.com/u/abunur)\ **Replies:** 4\ **Last updated:** [March 6, 2022, 3:05pm UTC](https://forums.kodeco.com/t/chapter-7-errata/50743 "2022-03-06T15:05:19Z")
“You’ll learn more about the syntax used to call the let function in the next section of the book.” Excerpt From: By Joe Howard. “Kotlin Apprentice.” Apple Books. The let function is actually never explained or address… --- ## [Typo in illustration "Adding your asynchronous sequence"](https://forums.kodeco.com/t/typo-in-illustration-adding-your-asynchronous-sequence/165776)
**Author:** [@hornebom](https://forums.kodeco.com/u/hornebom)\ **Replies:** 1\ **Last updated:** [March 2, 2022, 9:43am UTC](https://forums.kodeco.com/t/typo-in-illustration-adding-your-asynchronous-sequence/165776 "2022-03-02T09:43:04Z")
--- ## [Book has no keyword index?](https://forums.kodeco.com/t/book-has-no-keyword-index/165294)
**Author:** [@fluffycritter](https://forums.kodeco.com/u/fluffycritter)\ **Replies:** 5\ **Last updated:** [March 1, 2022, 4:22pm UTC](https://forums.kodeco.com/t/book-has-no-keyword-index/165294 "2022-03-01T16:22:19Z")
Hi, I recently purchased the textbook version of Metal by Tutorials since I’ve always found that to be an easier way to learn about things especially since I tend to flip back and forth between sections as I go, and I wa… --- ## [Basic tip to share - Prototyping](https://forums.kodeco.com/t/basic-tip-to-share-prototyping/163379)
**Author:** [@naplesdave](https://forums.kodeco.com/u/naplesdave)\ **Replies:** 2\ **Last updated:** [February 26, 2022, 3:29am UTC](https://forums.kodeco.com/t/basic-tip-to-share-prototyping/163379 "2022-02-26T03:29:01Z")
For newbies; Before you sit down and start coding away it is always a good idea to create a layout of what your proposed application will look like and how it is navigated. There are many tools out there to help you with… --- ## [CH4, Stacks reviewing code](https://forums.kodeco.com/t/ch4-stacks-reviewing-code/161749)
**Author:** [@lac\_ekim](https://forums.kodeco.com/u/lac_ekim)\ **Replies:** 5\ **Last updated:** [February 24, 2022, 6:42pm UTC](https://forums.kodeco.com/t/ch4-stacks-reviewing-code/161749 "2022-02-24T18:42:46Z")
Give me a rundown on this please, check to make sure I did this correctly. // Copyright (c) 2021 Razeware LLC // For full license & permission details, see LICENSE.markdown. public struct Stack\ { private va… --- ## [Geometry Reader/Size of Child Views](https://forums.kodeco.com/t/geometry-reader-size-of-child-views/165302)
**Author:** [@lducot2](https://forums.kodeco.com/u/lducot2)\ **Replies:** 1\ **Last updated:** [February 25, 2022, 6:46pm UTC](https://forums.kodeco.com/t/geometry-reader-size-of-child-views/165302 "2022-02-25T18:46:05Z")
Hi - Hoping someone can point me to a resource/book chapter that will help me solve an issue I am unable to figure out. I have an HStack of 30 views embedded in a Scroll View. I’d like to show 3 at a time. I have trie… --- ## [Sqlite Encryption about Chapter 15 -- Part 15.2 and 15.3](https://forums.kodeco.com/t/sqlite-encryption-about-chapter-15-part-15-2-and-15-3/165428)
**Author:** [@durul](https://forums.kodeco.com/u/durul)\ **Replies:** 0\ **Last updated:** [February 24, 2022, 3:39pm UTC](https://forums.kodeco.com/t/sqlite-encryption-about-chapter-15-part-15-2-and-15-3/165428 "2022-02-24T15:39:49Z")
Hi guys, I have a question about Sqlite encryption. As you know parts 15.1 and 15.2 pointed out two pub packages sqflite: ^2.0.2 & sqlbrite: ^2.2.0. But If I would like to encrypt the database, I can use sqflite\_sqlciph… --- ## [Chapter 13 - Ingredients not being removed](https://forums.kodeco.com/t/chapter-13-ingredients-not-being-removed/165404)
**Author:** [@cammy\_wammy](https://forums.kodeco.com/u/cammy_wammy)\ **Replies:** 0\ **Last updated:** [February 24, 2022, 9:39am UTC](https://forums.kodeco.com/t/chapter-13-ingredients-not-being-removed/165404 "2022-02-24T09:39:06Z")
When we remove a Recipe bookmark by pressing the delete icon in the bookmarks tab, our Ingredients from the Shopping List tab does not get deleted. How can one implement that the ingredients from a bookmarked recipe also… --- ## [Customize App Info Command Title](https://forums.kodeco.com/t/customize-app-info-command-title/165105)
**Author:** [@lducot2](https://forums.kodeco.com/u/lducot2)\ **Replies:** 2\ **Last updated:** [February 23, 2022, 10:48pm UTC](https://forums.kodeco.com/t/customize-app-info-command-title/165105 "2022-02-23T22:48:49Z")
Hello - I am trying to find the correct way to customize the title of the app info command menu. I may not be using the right terminology here, but the UI element I am referring to is the menu that is between the Apple … --- ## [Errata for Apple Augmented Reality by Tutorials 1st Edition](https://forums.kodeco.com/t/errata-for-apple-augmented-reality-by-tutorials-1st-edition/109440)
**Author:** [@mandafrederick](https://forums.kodeco.com/u/mandafrederick)\ **Replies:** 25\ **Last updated:** [February 22, 2022, 8:53pm UTC](https://forums.kodeco.com/t/errata-for-apple-augmented-reality-by-tutorials-1st-edition/109440 "2022-02-22T20:53:19Z")
Creating this topic to catch any typos or bugs in the 1st Edition of Apple Augmented Reality by Tutorials. --- ## [\[Chapter 4\] Is this code incorrect?](https://forums.kodeco.com/t/chapter-4-is-this-code-incorrect/165150)
**Author:** [@kuldip\_wagh](https://forums.kodeco.com/u/kuldip_wagh)\ **Replies:** 2\ **Last updated:** [February 22, 2022, 1:10pm UTC](https://forums.kodeco.com/t/chapter-4-is-this-code-incorrect/165150 "2022-02-22T13:10:41Z")
I am not getting the expected output due to these changes at this location. Does author should be creating device.makeBuffer and then setVertexStride here? There seem to be duplicate code. Is it intentional? I am ki… --- ## [Chapter 23: Coroutines - starter fails to open](https://forums.kodeco.com/t/chapter-23-coroutines-starter-fails-to-open/85598)
**Author:** [@chuck\_taylor](https://forums.kodeco.com/u/chuck_taylor)\ **Replies:** 12\ **Last updated:** [February 22, 2022, 11:32am UTC](https://forums.kodeco.com/t/chapter-23-coroutines-starter-fails-to-open/85598 "2022-02-22T11:32:48Z")
I cannot seem to get the starter file for Chapter 23 to run. Attached is a screengrab of the error I receive. Any ideas for getting this up and running? --- ## [Chapter 24 Scripting with Kotlin](https://forums.kodeco.com/t/chapter-24-scripting-with-kotlin/150114)
**Author:** [@220284hk](https://forums.kodeco.com/u/220284hk)\ **Replies:** 7\ **Last updated:** [February 22, 2022, 6:03am UTC](https://forums.kodeco.com/t/chapter-24-scripting-with-kotlin/150114 "2022-02-22T06:03:44Z")
Click the Refactor button to finish renaming the file. Next, you’ll need to manually clear the context of the script by going to Tools \> Tasks and Contexts \> Clear Context. This doesn’t seem to be an option on my Intell… --- ## [Learnings Paths vs Books at Ray Wenderlich](https://forums.kodeco.com/t/learnings-paths-vs-books-at-ray-wenderlich/155490)
**Author:** [@helvecio](https://forums.kodeco.com/u/helvecio)\ **Replies:** 2\ **Last updated:** [February 22, 2022, 12:06am UTC](https://forums.kodeco.com/t/learnings-paths-vs-books-at-ray-wenderlich/155490 "2022-02-22T00:06:29Z")
Hi, all. Would anyone please briefly comment on books vs learning paths at RW? It can be focussed on Flutter, since I’m on the Apprentice Book right now. I was wondering whether I should learn through one rather than thr… --- ## [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… --- ## [Advance key root](https://forums.kodeco.com/t/advance-key-root/165060)
**Author:** [@southernpe](https://forums.kodeco.com/u/southernpe)\ **Replies:** 0\ **Last updated:** [February 20, 2022, 4:11am UTC](https://forums.kodeco.com/t/advance-key-root/165060 "2022-02-20T04:11:07Z")
With this App, you can root your Android device with the aid of a simple operation. It is one of the most popular and best apps in the world. Rooting your Android device is easier than ever with this app without a comput… --- ## [Ch. 9: Where are EnvironmentValues' possible values documented?](https://forums.kodeco.com/t/ch-9-where-are-environmentvalues-possible-values-documented/165013)
**Author:** [@jimmythesaint](https://forums.kodeco.com/u/jimmythesaint)\ **Replies:** 4\ **Last updated:** [February 20, 2022, 6:59pm UTC](https://forums.kodeco.com/t/ch-9-where-are-environmentvalues-possible-values-documented/165013 "2022-02-20T18:59:52Z")
I see lists of EnvironmentValues documented online, but not the possible values each one can be set to. For example, verticalSizeLimit can be .compact and .regular, but where are .compact and .regular documented in relat… --- ## [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… --- ## [Chapter 1 - Saving to Core Data - Error message](https://forums.kodeco.com/t/chapter-1-saving-to-core-data-error-message/164739)
**Author:** [@theendofstart](https://forums.kodeco.com/u/theendofstart)\ **Replies:** 5\ **Last updated:** [February 19, 2022, 4:24pm UTC](https://forums.kodeco.com/t/chapter-1-saving-to-core-data-error-message/164739 "2022-02-19T16:24:49Z")
After folloring the code examples from the 1st Chapter, I got an error message. I’m not sure what selector where was sent. I’d really appreciate if someone point me where exactly was a mistake. -\[TestList.ViewController… --- ## [LinkedList Challenge Solution 3](https://forums.kodeco.com/t/linkedlist-challenge-solution-3/148575)
**Author:** [@happiehappie](https://forums.kodeco.com/u/happiehappie)\ **Replies:** 2\ **Last updated:** [February 19, 2022, 3:01pm UTC](https://forums.kodeco.com/t/linkedlist-challenge-solution-3/148575 "2022-02-19T15:01:42Z")
extension LinkedList { mutating func reverse() { // 1 let tmpList = LinkedList\() for value in self { tmpList.push(value) } // 2 head = tmpList.head } } For the easy way, the l… --- ## [5 Data Layer — Caching, Implementing the cross-reference table](https://forums.kodeco.com/t/5-data-layer-caching-implementing-the-cross-reference-table/165022)
**Author:** [@mr\_strelchuk](https://forums.kodeco.com/u/mr_strelchuk)\ **Replies:** 0\ **Last updated:** [February 19, 2022, 12:23pm UTC](https://forums.kodeco.com/t/5-data-layer-caching-implementing-the-cross-reference-table/165022 "2022-02-19T12:23:19Z")
Hi all, I’m a little bit confused by this: @Entity( primaryKeys = \["animalId", "tag"\], // 1 indices = \[Index("tag")\] // 2 ) data class CachedAnimalTagCrossRef( val animalId: Long, val tag: String ) Y… --- ## [Failed to compile starter application of CH8](https://forums.kodeco.com/t/failed-to-compile-starter-application-of-ch8/164875)
**Author:** [@frank2085](https://forums.kodeco.com/u/frank2085)\ **Replies:** 1\ **Last updated:** [February 17, 2022, 4:15pm UTC](https://forums.kodeco.com/t/failed-to-compile-starter-application-of-ch8/164875 "2022-02-17T16:15:40Z")
I just started reading Chapter 8 of the book Flutter Apprentice. I opened the starter project of this chapter in latest Android Studio (Bumblebee 2021.1.1 Patch 1). I tried running main.dart in Chrome (web), but failed. … --- ## [About isKnownUniquelyReferenced funcgtion](https://forums.kodeco.com/t/about-isknownuniquelyreferenced-funcgtion/164730)
**Author:** [@richmond\_jam](https://forums.kodeco.com/u/richmond_jam)\ **Replies:** 0\ **Last updated:** [February 16, 2022, 8:42am UTC](https://forums.kodeco.com/t/about-isknownuniquelyreferenced-funcgtion/164730 "2022-02-16T08:42:07Z")
Hello, I have a question about this function on title. If I have a class inherit NSObject and I test isKnownUniquelyReferenced, it always return false when the parameter is singleton. --- ## [2nd Ed Chapter 5 , section 5- Cocoapods error](https://forums.kodeco.com/t/2nd-ed-chapter-5-section-5-cocoapods-error/163380)
**Author:** [@naplesdave](https://forums.kodeco.com/u/naplesdave)\ **Replies:** 21\ **Last updated:** [February 15, 2022, 6:40am UTC](https://forums.kodeco.com/t/2nd-ed-chapter-5-section-5-cocoapods-error/163380 "2022-02-15T06:40:21Z")
I am using Android Studio BumbleBee on a MacBook Pro. I have the starter code loaded and it worked prior to the step to put the code into explore\_screen.dart. Now the app will not run. It states; Warning: CocoaPods not … --- ## [I get an error building the Vapor Project!? Chapter 7](https://forums.kodeco.com/t/i-get-an-error-building-the-vapor-project-chapter-7/43395)
**Author:** [@dkoenig82](https://forums.kodeco.com/u/dkoenig82)\ **Replies:** 12\ **Last updated:** [February 14, 2022, 1:37am UTC](https://forums.kodeco.com/t/i-get-an-error-building-the-vapor-project-chapter-7/43395 "2022-02-14T01:37:45Z")
Here is the Error, nothing works with!? Generating Xcode Project \[Failed\] error: terminated(72): xcrun --sdk macosx --find xctest output: Error: Could not generate Xcode project: error: terminated(72): xcrun --sdk mac… --- ## [Winding order for clarity](https://forums.kodeco.com/t/winding-order-for-clarity/164492)
**Author:** [@harmansmith](https://forums.kodeco.com/u/harmansmith)\ **Replies:** 1\ **Last updated:** [February 14, 2022, 12:15am UTC](https://forums.kodeco.com/t/winding-order-for-clarity/164492 "2022-02-14T00:15:17Z")
Hello! If you don’t mind, I want to clarify a couple of points. Chapter 3 says: “For efficiency, you should set winding order and enable back-face culling in the pipeline state.” However, func setFrontFacing(\_ frontFa… --- ## [Chapter 2: Segmentation Fault after first .task modifier](https://forums.kodeco.com/t/chapter-2-segmentation-fault-after-first-task-modifier/164477)
**Author:** [@sneakysnail](https://forums.kodeco.com/u/sneakysnail)\ **Replies:** 1\ **Last updated:** [February 13, 2022, 7:00am UTC](https://forums.kodeco.com/t/chapter-2-segmentation-fault-after-first-task-modifier/164477 "2022-02-13T07:00:35Z")
When going through the process of building out the Storage app, right as we get into our work with the .task {} modifier on ListView, I place in the code to call availableFiles. After doing this, I get a crash on account… --- ## [Chapter 10 build\_runner error](https://forums.kodeco.com/t/chapter-10-build-runner-error/160911)
**Author:** [@feralbit](https://forums.kodeco.com/u/feralbit)\ **Replies:** 4\ **Last updated:** [February 12, 2022, 4:31pm UTC](https://forums.kodeco.com/t/chapter-10-build-runner-error/160911 "2022-02-12T16:31:57Z")
When I run the command flutter pub run build\_runner build I get the response: Your Flutter application is created using an older version of the Android embedding. It is being deprecated in favor of Android embedding v… --- ## [Chapter 9 - Fatal error: Unexpectedly found nil while unwrapping an Optional value](https://forums.kodeco.com/t/chapter-9-fatal-error-unexpectedly-found-nil-while-unwrapping-an-optional-value/164393)
**Author:** [@theendofstart](https://forums.kodeco.com/u/theendofstart)\ **Replies:** 2\ **Last updated:** [February 12, 2022, 2:37pm UTC](https://forums.kodeco.com/t/chapter-9-fatal-error-unexpectedly-found-nil-while-unwrapping-an-optional-value/164393 "2022-02-12T14:37:41Z")
Input: xcode 12.0. UIKIt Apprentice First Edition I finished a few steps on Chapter 9 where override func tableView(\_ tableView: UITableView, cellForRowAt indexPath: IndexPath) → UITableViewCell {} were update with l… --- ## [Chapter 8 - Why doesn't Download task run twice?](https://forums.kodeco.com/t/chapter-8-why-doesnt-download-task-run-twice/164358)
**Author:** [@hirohuntexp](https://forums.kodeco.com/u/hirohuntexp)\ **Replies:** 1\ **Last updated:** [February 11, 2022, 10:01am UTC](https://forums.kodeco.com/t/chapter-8-why-doesnt-download-task-run-twice/164358 "2022-02-11T10:01:09Z")
Thank you for making a very practical book. I have a questions about the image cache mechanism introduced in Chapter 8. The following is it. \[Question\] Why doesn’t Download task run twice? When the image cache does n… [Previous page](https://forums.kodeco.com/c/books/6.md?page=29) [Next page](https://forums.kodeco.com/c/books/6.md?page=31)