# šŸ“š Official Books **URL:** https://forums.kodeco.com/c/books/6.md?page=133 [Latest](https://forums.kodeco.com/latest.md) Ā· [Categories](https://forums.kodeco.com/categories.md) Ā· [Tags](https://forums.kodeco.com/tags.md) **Page:** 134 --- ## [Can't run RxSwift Playground examples](https://forums.kodeco.com/t/cant-run-rxswift-playground-examples/34707)
**Author:** [@enti](https://forums.kodeco.com/u/enti)\ **Replies:** 2\ **Last updated:** [September 22, 2017, 12:29pm UTC](https://forums.kodeco.com/t/cant-run-rxswift-playground-examples/34707 "2017-09-22T12:29:13Z")
I am getting error ā€œworkspace integrity : couldnā€™t load project rxswift.playgroundā€. Playground file not even opening in the project when I tap on it. I tried to install latest cococapods, cleaning, deleting derivedā€¦ --- ## [Chapter 2: Asset catalogs - issue with background color](https://forums.kodeco.com/t/chapter-2-asset-catalogs-issue-with-background-color/22582)
**Author:** [@ilmaros](https://forums.kodeco.com/u/ilmaros)\ **Replies:** 4\ **Last updated:** [September 22, 2017, 10:45am UTC](https://forums.kodeco.com/t/chapter-2-asset-catalogs-issue-with-background-color/22582 "2017-09-22T10:45:26Z")
Iā€™m using Xcode (8.1), and there have to be blue background color, but I get black one! I get the same result when I run final project from the Bookā€™s resources of the 2nd chapter. Question is, how to resolve this to ā€¦ --- ## [Error Iphone 8 Xcode 9](https://forums.kodeco.com/t/error-iphone-8-xcode-9/34713)
**Author:** [@archideus](https://forums.kodeco.com/u/archideus)\ **Replies:** 2\ **Last updated:** [September 22, 2017, 6:43am UTC](https://forums.kodeco.com/t/error-iphone-8-xcode-9/34713 "2017-09-22T06:43:12Z")
2017-09-21 18:04:58.079750+0300 ZombieConga\[6480:772618\] 378: failed assertion: inChannelsPerFrame \>= 4 --- ## [Errata for iOS 11 by Tutorials v1.0](https://forums.kodeco.com/t/errata-for-ios-11-by-tutorials-v1-0/34474)
**Author:** [@thegamingart](https://forums.kodeco.com/u/thegamingart)\ **Replies:** 2\ **Last updated:** [September 21, 2017, 4:31pm UTC](https://forums.kodeco.com/t/errata-for-ios-11-by-tutorials-v1-0/34474 "2017-09-21T16:31:51Z")
The unofficial errata reports for iOS 11 By Tutorials v1.0. --- ## [Chapter 9(Core ML) -No green rectangle appears after building](https://forums.kodeco.com/t/chapter-9-core-ml-no-green-rectangle-appears-after-building/34651)
**Author:** [@ihappyfish](https://forums.kodeco.com/u/ihappyfish)\ **Replies:** 1\ **Last updated:** [September 20, 2017, 1:26pm UTC](https://forums.kodeco.com/t/chapter-9-core-ml-no-green-rectangle-appears-after-building/34651 "2017-09-20T13:26:51Z")
hi, I might need your help when learning Chapter 9 (Core ML) After I followed instructions through page 186, no green rectangle appears after building both on iOS Simulator and on my iPhone 6s plus. Actually, it works ā€¦ --- ## [Chapter 6: Dismiss of alert box](https://forums.kodeco.com/t/chapter-6-dismiss-of-alert-box/34463)
**Author:** [@tkallioras](https://forums.kodeco.com/u/tkallioras)\ **Replies:** 8\ **Last updated:** [September 19, 2017, 10:05am UTC](https://forums.kodeco.com/t/chapter-6-dismiss-of-alert-box/34463 "2017-09-19T10:05:31Z")
In the extension of the UIViewController we declare an alert function like this: func alert(title: String, text: String?) -\> Observable\ { return Observable.create { \[weak self\] observer in let alertVC = ā€¦ --- ## [Tweetie App Podfile for XCode9/Swift4](https://forums.kodeco.com/t/tweetie-app-podfile-for-xcode9-swift4/34564)
**Author:** [@ssaylanc](https://forums.kodeco.com/u/ssaylanc)\ **Replies:** 1\ **Last updated:** [September 19, 2017, 8:14am UTC](https://forums.kodeco.com/t/tweetie-app-podfile-for-xcode9-swift4/34564 "2017-09-19T08:14:39Z")
Hi, I am using Swift 4, and I couldnā€™t get install the pods. Is there anyone with an updated pod file for swift4? Thanks, --- ## [Menu Scene Darkness Issue](https://forums.kodeco.com/t/menu-scene-darkness-issue/34473)
**Author:** [@dcorp](https://forums.kodeco.com/u/dcorp)\ **Replies:** 2\ **Last updated:** [September 18, 2017, 11:18pm UTC](https://forums.kodeco.com/t/menu-scene-darkness-issue/34473 "2017-09-18T23:18:39Z")
On page 315 after adding the menu scene, my scene lightning for the game looks dark. At the end of the page it says, ā€œHowever you might notice the game looks a lot darker. If the lighting looks fine, skip ahead to the Muā€¦ --- ## [Weak & unowned self inside operators](https://forums.kodeco.com/t/weak-unowned-self-inside-operators/34487)
**Author:** [@tkallioras](https://forums.kodeco.com/u/tkallioras)\ **Replies:** 1\ **Last updated:** [September 17, 2017, 11:34am UTC](https://forums.kodeco.com/t/weak-unowned-self-inside-operators/34487 "2017-09-17T11:34:19Z")
While going through the book, a question popped up: When I declare a self property inside a closure of a function in a UIViewController class, I make it unowned. The rationale is that for the lifetime of the VC, self caā€¦ --- ## [07 - List, the Cancel and Done buttons not work when I Edit Checklist](https://forums.kodeco.com/t/07-list-the-cancel-and-done-buttons-not-work-when-i-edit-checklist/34407)
**Author:** [@yifans](https://forums.kodeco.com/u/yifans)\ **Replies:** 2\ **Last updated:** [September 15, 2017, 7:44am UTC](https://forums.kodeco.com/t/07-list-the-cancel-and-done-buttons-not-work-when-i-edit-checklist/34407 "2017-09-15T07:44:35Z")
When I Add Checklist, the Cancel And Done button is ok, I can add Checklist or Cancel. When I press accessory button to Edit Checklist screen, I can edit Checklist, but the Cancel And Done buttons donā€™t have any responā€¦ --- ## [Errors create nsmanagedobject subclass](https://forums.kodeco.com/t/errors-create-nsmanagedobject-subclass/32848)
**Author:** [@brower](https://forums.kodeco.com/u/brower)\ **Replies:** 7\ **Last updated:** [September 14, 2017, 3:33am UTC](https://forums.kodeco.com/t/errors-create-nsmanagedobject-subclass/32848 "2017-09-14T03:33:03Z")
When I Create NSManagedObject Subclass I get about 10 errors in the two files that get created. What should I check? --- ## [Chapter 2 unable to generate NSManagedObjected Subclass with Xcode 8](https://forums.kodeco.com/t/chapter-2-unable-to-generate-nsmanagedobjected-subclass-with-xcode-8/20809)
**Author:** [@yungdai](https://forums.kodeco.com/u/yungdai)\ **Replies:** 2\ **Last updated:** [September 13, 2017, 6:04pm UTC](https://forums.kodeco.com/t/chapter-2-unable-to-generate-nsmanagedobjected-subclass-with-xcode-8/20809 "2017-09-13T18:04:30Z")
Iā€™m going through Chapter 2 and Iā€™m finding that I cannot generate the subclasses for CoreData, even when I do a clean project from scratch. Is this a bug with Xcode 8? --- ## [Want to know when I need to use flatMap](https://forums.kodeco.com/t/want-to-know-when-i-need-to-use-flatmap/34322)
**Author:** [@lohanrakesh](https://forums.kodeco.com/u/lohanrakesh)\ **Replies:** 1\ **Last updated:** [September 13, 2017, 3:23pm UTC](https://forums.kodeco.com/t/want-to-know-when-i-need-to-use-flatmap/34322 "2017-09-13T15:23:31Z")
Hi @scotteg just want to know when I should use flatMap and can I use flat map without having return type observable flatMap { $0.score.asObservable() } I need some reason to implement it. Please help me . Thanks ~ā€¦ --- ## [iOS Apprentice page 167](https://forums.kodeco.com/t/ios-apprentice-page-167/33967)
**Author:** [@coltkell](https://forums.kodeco.com/u/coltkell)\ **Replies:** 2\ **Last updated:** [September 13, 2017, 1:07am UTC](https://forums.kodeco.com/t/ios-apprentice-page-167/33967 "2017-09-13T01:07:28Z")
I cannot run the app based on the instructions on page 168 of which page 167 shows the code. An error occurs because tableView.deselectRow(at: indexPath, animated: true) is not declared. The red error indicated says "Uā€¦ --- ## [Show segue VS Present Modally segue](https://forums.kodeco.com/t/show-segue-vs-present-modally-segue/34286)
**Author:** [@jiang](https://forums.kodeco.com/u/jiang)\ **Replies:** 1\ **Last updated:** [September 12, 2017, 12:18pm UTC](https://forums.kodeco.com/t/show-segue-vs-present-modally-segue/34286 "2017-09-12T12:18:01Z")
Hi, There are many types of segue, Iā€™m a little bit confused about when should I use certain type of segue. Anyone can give some examples or principles I can follow? Thanks!:slight\_smile: --- ## [Curious about try?NSData(contentsOFURL)](https://forums.kodeco.com/t/curious-about-try-nsdata-contentsofurl/33498)
**Author:** [@jiang](https://forums.kodeco.com/u/jiang)\ **Replies:** 3\ **Last updated:** [September 12, 2017, 9:12am UTC](https://forums.kodeco.com/t/curious-about-try-nsdata-contentsofurl/33498 "2017-09-12T09:12:56Z")
Hi fellows, Iā€™m curious about what try?NSData(contentsOFURL) would return if the file doesnā€™t exist. I didnā€™t see the tutorial checks if the file exists, however, my app gets crushed without checking the existence of ā€¦ --- ## [Chapter 17 - Attaching the mesh to the armatureā€™ to work](https://forums.kodeco.com/t/chapter-17-attaching-the-mesh-to-the-armature-to-work/34108)
**Author:** [@nick2905](https://forums.kodeco.com/u/nick2905)\ **Replies:** 11\ **Last updated:** [September 11, 2017, 3:45pm UTC](https://forums.kodeco.com/t/chapter-17-attaching-the-mesh-to-the-armature-to-work/34108 "2017-09-11T15:45:11Z")
Unity Games by Tutorials ā€“ Chapter 17. Hi, try as I may I canā€™t get the section ā€˜Attaching the mesh to the armatureā€™ to work. It keeps failing with the message ā€˜Bone Heat Weighting: failed to find solution for one or mā€¦ --- ## [Zombie Conga alternate game over strategy](https://forums.kodeco.com/t/zombie-conga-alternate-game-over-strategy/34178)
**Author:** [@spgms](https://forums.kodeco.com/u/spgms)\ **Replies:** 3\ **Last updated:** [September 11, 2017, 2:35pm UTC](https://forums.kodeco.com/t/zombie-conga-alternate-game-over-strategy/34178 "2017-09-11T14:35:42Z")
In Zombie Conga, instead of game over scenes with images, how would you do a fly-in label with ā€œwinā€ or ā€œloseā€ message and a button to ā€œplay againā€. Basically, keeping game and score visible behind label and button instā€¦ --- ## [Chapter 4: Intermediate Fetching Confusing moment](https://forums.kodeco.com/t/chapter-4-intermediate-fetching-confusing-moment/34159)
**Author:** [@simons1994](https://forums.kodeco.com/u/simons1994)\ **Replies:** 5\ **Last updated:** [September 11, 2017, 1:34pm UTC](https://forums.kodeco.com/t/chapter-4-intermediate-fetching-confusing-moment/34159 "2017-09-11T13:34:11Z")
Hi everyone! In the stater pack application appdelegate.swift file author using that function func importJSONSeedDataIfNeeded() { let fetchRequest = NSFetchRequest(entityName: ā€œVenueā€) let count = try! coreDataStack.mā€¦ --- ## [Q re creating selectedIndexPath var My Locations pg107](https://forums.kodeco.com/t/q-re-creating-selectedindexpath-var-my-locations-pg107/34194)
**Author:** [@flanker](https://forums.kodeco.com/u/flanker)\ **Replies:** 2\ **Last updated:** [September 11, 2017, 9:06am UTC](https://forums.kodeco.com/t/q-re-creating-selectedindexpath-var-my-locations-pg107/34194 "2017-09-11T09:06:38Z")
In creating the category picker, you instantiate the var selectedIndexPath = IndexPath() but as far as I can see never use that initial object, just to replace it with a new one during viewDidfLoad. Wouldnā€™t it be betā€¦ --- ## [When saving to CoreData from Today Extension, Data only accesable from Widget - NOT from Main Application](https://forums.kodeco.com/t/when-saving-to-coredata-from-today-extension-data-only-accesable-from-widget-not-from-main-application/25762)
**Author:** [@lks](https://forums.kodeco.com/u/lks)\ **Replies:** 1\ **Last updated:** [September 11, 2017, 5:26am UTC](https://forums.kodeco.com/t/when-saving-to-coredata-from-today-extension-data-only-accesable-from-widget-not-from-main-application/25762 "2017-09-11T05:26:24Z")
Iā€™m writing an Application for iOS with Swift 3. In my Main iOS App Iā€™m using an NSFetchedResultsController to show saved items as an TableView. Itā€™s (of course) possible to add new items from another ViewController. ā€¦ --- ## [UIAlertController in Core Data by Tutorials](https://forums.kodeco.com/t/uialertcontroller-in-core-data-by-tutorials/26292)
**Author:** [@datahog](https://forums.kodeco.com/u/datahog)\ **Replies:** 2\ **Last updated:** [September 11, 2017, 5:20am UTC](https://forums.kodeco.com/t/uialertcontroller-in-core-data-by-tutorials/26292 "2017-09-11T05:20:48Z")
This compiles and runs but does not do anything. Have looked at other solutions on web but so far all are out of date. @IBAction func rate(\_ sender: AnyObject) { let alert = UIAlertController(title: ā€œNew Ratingā€, mesā€¦ --- ## [Errata for Core Data by Tutorials v3.1](https://forums.kodeco.com/t/errata-for-core-data-by-tutorials-v3-1/25293)
**Author:** [@tetanuss](https://forums.kodeco.com/u/tetanuss)\ **Replies:** 1\ **Last updated:** [September 11, 2017, 5:16am UTC](https://forums.kodeco.com/t/errata-for-core-data-by-tutorials-v3-1/25293 "2017-09-11T05:16:41Z")
In Chapter 6 ā€œVersioning and Migrating - sequential migrationā€ in Core Data by Tutorial v3.1 there is a difference between the text in the PDF and the corresponding final code. In the final code the request in NotesListVā€¦ --- ## [Editor placeholder in source file Dog Walk chapter](https://forums.kodeco.com/t/editor-placeholder-in-source-file-dog-walk-chapter/27665)
**Author:** [@rpetruzz](https://forums.kodeco.com/u/rpetruzz)\ **Replies:** 3\ **Last updated:** [September 11, 2017, 5:01am UTC](https://forums.kodeco.com/t/editor-placeholder-in-source-file-dog-walk-chapter/27665 "2017-09-11T05:01:48Z")
Iā€™m working through Chapter 3 Dog Walk and I have been successful in getting it to work using the example code in the chapter. EXCEPT, if I attempt to implement the suggestion below: ā€œFor example, you can replace the eā€¦ --- ## [Chapter 2 coreDataStack without VC](https://forums.kodeco.com/t/chapter-2-coredatastack-without-vc/24003)
**Author:** [@scottmetro](https://forums.kodeco.com/u/scottmetro)\ **Replies:** 2\ **Last updated:** [September 11, 2017, 4:56am UTC](https://forums.kodeco.com/t/chapter-2-coredatastack-without-vc/24003 "2017-09-11T04:56:58Z")
Hi, Chapter 2 assumes that all data operations are occurring in a View Controller but Iā€™m putting all of my data operations in its own file and class. Any ideas on how to pass the managedContext in AppDelegate to a reguā€¦ --- ## [My pdf chapter 7 miss](https://forums.kodeco.com/t/my-pdf-chapter-7-miss/22314)
**Author:** [@rokurouc](https://forums.kodeco.com/u/rokurouc)\ **Replies:** 1\ **Last updated:** [September 11, 2017, 4:52am UTC](https://forums.kodeco.com/t/my-pdf-chapter-7-miss/22314 "2017-09-11T04:52:28Z")
where is Chapter 7 ?? --- ## [Core Data and Watch OS](https://forums.kodeco.com/t/core-data-and-watch-os/24560)
**Author:** [@createch](https://forums.kodeco.com/u/createch)\ **Replies:** 1\ **Last updated:** [September 11, 2017, 4:47am UTC](https://forums.kodeco.com/t/core-data-and-watch-os/24560 "2017-09-11T04:47:36Z")
I have an iPhone app that uses Core Data. I would like to replicate the structure on the watch app extension. I can share the data structure between the two targets but I am not clear on how to implement the core data ā€¦ --- ## [Typo - Predicate should be NSPredicate](https://forums.kodeco.com/t/typo-predicate-should-be-nspredicate/21362)
**Author:** [@operator](https://forums.kodeco.com/u/operator)\ **Replies:** 2\ **Last updated:** [September 11, 2017, 4:39am UTC](https://forums.kodeco.com/t/typo-predicate-should-be-nspredicate/21362 "2017-09-11T04:39:21Z")
This is for version 3.0 of Core Data by Tutorials On page 189 fetchRequest.predicate = Predicate(format: "siteNumber == %@", argumentArray: \[siteNumber\]) should be fetchRequest.predicate = NSPredicate(format: "siteNuā€¦ --- ## [Any idea when the iOS Apprentice for Swift 4/iOS 11 will be available? :)](https://forums.kodeco.com/t/any-idea-when-the-ios-apprentice-for-swift-4-ios-11-will-be-available/34129)
**Author:** [@sekarb](https://forums.kodeco.com/u/sekarb)\ **Replies:** 3\ **Last updated:** [September 11, 2017, 4:30am UTC](https://forums.kodeco.com/t/any-idea-when-the-ios-apprentice-for-swift-4-ios-11-will-be-available/34129 "2017-09-11T04:30:42Z")
I am in the last tutorial of the swift 3 version. Wondering if itā€™s worth waiting for the swift 4 version so I donā€™t spend time learning the older version and the Xcode 8 :slightly\_smiling\_face: Sekar --- ## [Savig data in the Checklists tutorial](https://forums.kodeco.com/t/savig-data-in-the-checklists-tutorial/34160)
**Author:** [@sekarb](https://forums.kodeco.com/u/sekarb)\ **Replies:** 3\ **Last updated:** [September 11, 2017, 4:28am UTC](https://forums.kodeco.com/t/savig-data-in-the-checklists-tutorial/34160 "2017-09-11T04:28:03Z")
On the checklists tutorial, archiving is used to save data. Is that the recommended way to save that kind of data model or is it just used to introduce the concept of saving data with archives? I am trying to play withā€¦ [Previous page](https://forums.kodeco.com/c/books/6.md?page=132) [Next page](https://forums.kodeco.com/c/books/6.md?page=134)