playground.xcworkspace couldn't be saved because a file already exists - ios

I have been learning Swift in my spare time, and I am new to iOS development. I have been reading a book from Big Nerd Ranch that teaches me the basics of Swift programming. I have one directory for the book. For each chapter, I start a new Playground or Project, as each chapter recommends. The book recommends to create Playgrounds and Projects using MacOS (versus iOS or tvOS). Every so often, I am getting the following error:
The file "playground.xcworkspace" couldn't be saved in the folder "chxx-foo.playground" because a file with the same name already exists
To save the file, either provide a different name, or move aside or delete the existing file, and try again.
When I look into the directory for the playground, I always see only one playground.xcworkspace. The error seems innocuous, so I am not too concerned, just wondering if my development environment could be tweaked differently to avoid this message, or maybe I am doing something that is not idiomatic to iOS development.
How can I get rid of the error message that keeps coming up?

What worked for me was to go into the directory through Finder and rename it. It will generate a new one of the same name as the one you just renamed. After that, delete the one you just named, leaving the one it generated after you renamed it. Do this in a new Playground to test to make sure it works; however, it worked for me.

Related

Transferring Xcode Project from one computer to another brings random errors?

I have a Xcode project I got from another developer. Initially when I opened it it has a bunch of errors (most of which were un-updated frameworks). I got it to work after a while and I fixed it. I want pass it back to the manager since I'm leaving uni in a few months. I copied it over to my friends Mac to see what would happen if I just took the project and all it's folders and made it a zipfile. It didn't work for some reason. It gave me an error:
error: using bridging headers with framework targets is unsupported
But why did that come up? I mean it's the same code on the slightly different versions of Xcode (13.1 versos 14.1) but I doubt there was a massive change between the two that would cause this. I want to be able to pass these app later in the future without having to care about this stuff. I made a GitHub (link below) would cloning that work? Also the laptop I chose was just a fresh reset. Would it be due to not having coco-pods installed?
I feel like I could go through and fix it all on that laptop and document that but then I'm afraid that every time I put it on a new one it would come up with random errors every single time making my documentation moot.
https://github.com/AbdullahMSaid/SonicExperiment-Works
With big help this was Fixed.
Things that fixed it.
Having the correct version of Xcode
Turning everything from absolute path to relative
Lots of other code fixes. But those are my project specific.
You don't need bridging headers in framework. Use should have something like "YourFramework.h" where you can import your .h files.

Reusing core data model when updating app - from scratch

My question is fairly simple though I couslnt find anything specifically answering it till yet.
I have an obj-c app that I'm updating fairly often. I would like to create a new swift app with the same bundle id to replace the older one as an update. I have like 8 core data model versions within my old app that I would love to migrate to the new swift-from-scratch-app, so my users wont lose their data. Is it even possible??
Thank u
If you're using the exact same bundle ID (this is key), then from the perspective of iOS, it is considered exactly the same app. Consider your users having version 1.x of your app installed on their devices and you release 2.x using your new Swift project. Your user, nor iOS, will be able to tell this is a brand new app written in Swift.
The gotcha here is that unless you use the exact same model names, CoreData won't be able to be initialized with existing data and you'll be forced to write a custom migration for this.
My suggestion to you is to copy the xcdatamodel file from your old project and change the language of the code it generates once copied into the new project.
Then regenerate your entities in Swift and continue working like nothing ever happened.

How to start a new project in Swift

I just start to learn Swift and have little background in programming.
I am trying to use Swift to make a to-do list. Before starting a new project in Swift, I deleted the previous to-do project, which I use objective-c to write.
I used the same name as the project name and the path is the same (on the Desktop).
After I put several new views on the storyboard, I run it. It turns out to be the old project, even though I have deleted the old files completely[empty the trash can].
You see I add no entry in the table view.
but after run it, I get
These static entries are from my previous project.
I just wonder how I can get rid of my previous project.
Any helps will be appreciated!
I think you answered the question yourself. Clearly the problem is that you have remnants of your old program, so start a new project with a different name. You probably deleted references to your old files, but did not delete the files themselves. Xcode is great about dragging & dropping in files from other projects, or just copy & paste the relevant code from this project into a new one. Also, the Xcode Beta is a little buggy, so a restarting Xcode, or even a good old-fashion re-boot can never hurt. I've gotten Xcode into a couple funky states that required killing it and re-starting.

Coredata inferred mapping model is failing on my old databases

I'm using CoreData for one of my databases, and I'm having trouble with an upgrade to my App.
My old databases are no longer loading ... I get the error "Cocoa error 134190" which I believe means that the inferred mapping model is failing.
When I started editing this version of my App, I created a new model version, and I simply added one new attribute to one entity, and two new attributes to another entity. Nothing was changed or deleted.
I've checked inside my App's directory, and all of the model versions are there.
I even have a snapshot of my previous version of the App, and with that snapshot I can load my core data files.
To debug what is going wrong, I took the exact data model from my previous snapshot and used it in my current version, and I still get the error.
I've even done a "diff" on every file in my ".app" directory packages, and there are only two files that are different between the two. One is the actual binary for the application, and the other is the "Info.plist" file. I looked at the Info.plist files, and they too are basically identical (the new one has a newer bundle version, but no other change).
Any idea why the inferred mapping is broken?
I am getting the same error even when the data models are completely unchanged from my last version which works.
This is extremely frustrating.
Any information as to how to track down problems like this in the future would also be greatly appreciated!!!
I found the answer ... the problem was that in my new version, I was rearranging the locations of my files. I did so by simply moving the database to a new location. What I didn't realize is that coredata databases have some knowledge of their path built in, and you can't simply move them.
I needed to change the location of the database using the NSPersistentStoreCoordinator's method:
migratePersistentStore:toURL:options:withType:error:
My fault, but I really wish that core data error messages weren't so cryptic.
In the next version of my App, I'm going to remove core data completely.
Ron
I don't believe core data actually cares where the database file is, but I could be wrong. In the times I have seen this error, specifically "Cocoa error 134190" while trying to infer a model mapping, it's been the case that there was actually a problem trying to migrate to the next version of the model.
For example, when I found this thread today because I was helping someone with this problem, the real underlying issue was that the type of one of the attributes was accidentally changed. The automatic migration can't handle that sort of change.
A somewhat easy way to look at the changes between two model versions is to diff the description files themselves on the command line with diff:
diff yourNameHere.xcdatamodeld/yourNameHere5.xcdatamodel/contents yourNameHere.xcdatamodeld/yourNameHere4.xcdatamodel/contents
(That assumes you have a core data model description named "yourNameHere" and you're looking at a problem migrating from version 4 to 5. You'll have to adjust for your specific files.) In this diff you should see whatever additional things you've added, but you're really looking for something like a type changing when it shouldn't.

Using one xcdatamodelId in two app

I created one project with core data that will work with unchangeable database. And I don't want to write code in this project , that will programmatically populate this database. So, I create second project with core data, add existing xcdatamodel from first project without copying(only references). There i populate my database, open it with mozilla plug-in and it successfully filled. Then I copy ,my *.sqlite file and manually replace it with old file in first project. It causes error:"The model used to open the store is incompatible with the one used to create the store". But I use for both files the same xcdatamodelid. Where my error?
Sorry for my english, I really need help.
P.S. when I open sqlite file from first project and second (with commented code of populate base) in FileMerge - second is already empty. I appreciate any advice or help.
Karoly S nicely answers the question. I have a hint that I frequently employ that may prevent this out of sync situation. Instead of two Xcode projects trying to share one model file, just create one Xcode project with two targets. Each target will use the same model file, any class definitions derived from that model, and possibly other code. My second target is a Mac OS command line program that generates the database, while my first target continues to be the iOS app that reads that database. The Mac OS target will overwrite the database file in a project subdirectory, ensuring it's up-to-date. If I make any changes to the model, Xcode knows to update both targets.
Did you change your Model Definitions in any way? The error you are seeing is because there is some difference between the model from when you created it, and again from when you are trying to reference it. Are you running on the simulator? Try to delete both of your apps to clear the data related to it, as it might be out of date. Afterwards simply rebuild both of your projects as that will update your core data database.
EDIT: To clarify a bit more, your core data model is out of sync, this is generally caused by you building and running an app, and a database being created, then redefining your object model, this can be done in a variety of ways, most likely caused by the addition of an attribute or entity. So when you are trying to load the database there are fields that the app and core data are looking for, but are not there because they did not exist when the database was created. I hope this helps.

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