Using Version 8.1 of Xcode.
Create an entity named "MapRegionObject" in .xcdatamodeld file.
Using auto code generator, click Editor on the navigation bar -> create NSManagedOject Subclass...
Got two files : MapRegionObject+CoreDataClass.swift and MapRegionObject+CoreDataProperties
Errors in two files showing in the screenshot:
MapRegionObject+CoreDataClass.swift
MapRegionObject+CoreDataProperties
Please help me fix this bugs, thank you so much!
In Xcode 8.1, before using the auto code generator, you must select the entity in your data model:
Then go to the Data Model Inspector tab:
Under "Codegen" select "Manual/Node"
After that you could create a NSManagedObject subclass without errors.
Alternatively, if you have already used 'Class Definition', you can go into your existing .xcdatamodeld file and set all current entities to 'Manual/None' under Codegen. Make sure to save your project (File -> Save), delete your existing Derived Data, clean the project, and then build. Resolved it for me without having to re-make my whole model.
I found this whole thing to be very confusing. You really do need to understand what's new in CoreData. Basically, the default is to automatically generate the class and the extensions for you in a place called "DerivedData" that's buried in ~/Library/Developer/Xcode/DerivedData where these classes and their extensions live, outside of your code source. Personally, not being able to open and look at them is weird to me, but something to get used it.
Basically, if you have an entity called "AppSettings" in your CoreData model, you can just use it without needing to generate the code yourself. If you want the code in your project, then set the Codegen property on the entity to Manual/None. Then do what you did before: Editor->Create NSManagedObject classes, etc. The files will wind up in your project.
The good news is that if you want to make custom extensions, just do that in your project. Xcode will blend the generated files, from their other place outside your project directory, with the files in your project directory.
1) clean the project (cmd + shift + K)
2) In the "data model inspector" for every created Entity set attributes for Class just as in the screenshot below
3) Generate code again (Editor -> create NSManagedObject Subclasses)
After that everything should work fine.
The problem is that you don't need to generate NSManagedObjectModel subclasses manually anymore.
ref: https://forums.developer.apple.com/thread/48988
Xcode automatically generates classes or class extensions for the
entities and properties in a Core Data data model. Automatic code
generation is enabled and disabled on an entity by entity basis, and
is enabled for all entities in new models using the Xcode 8 file
format. This feature is available for any data model that has been
upgraded to the Xcode 8 format. You specify whether Xcode generates
Swift or Objective-C code for a data model using the data model’s file
inspector. When automatic code generation is enabled for an entity,
Xcode creates either a class or class extension for the entity as
specified in the entity's inspector: the specified class name is used
and the sources are placed in the project’s Derived Data. For both
Swift and Objective-C, these classes are directly usable from the
project’s code. For Objective-C, an additional header file is created
for all generated entities in your model: The file name conforms to
the naming convention 'DataModelName+CoreDataModel.h'.
Close the project and follow the following instructions:
Reveal in finder your database .xcdatamodeld file.
on .xcdatamodeld file right click -> Show Package Contents, if(.xcdatamodel) is find again in the package again right click and 'Show Package Contents'. you should get 'contents' file.
Open 'contents' in text edit.
Command-F (codeGenerationType="class") and replace all matchings string with blank string.
Save and open Xcode project again.Everything should work well.
In Xcode 8.2.1 , Menu-Product-Clean，And every is ok, it's so verid.
Don't fight the with Xcode on this unless you really need to alter your generated properties, doing so will just leave you frustrated.
Think of the auto-generated class as any other class in your application. If you need to add functionality to your managed object class, simply change your class definition into an extension and extend your object.
change your class:
class MyManagedObject : NSManagedObject { /* implementation*/ }
to an extension:
extension MyManagedObject { /* implementation */ }
This isn't an answer. It's just explanation of what's going on with the selections
Make sure you see this moment for the Core Data Stanford course
Below is a transcript I wrote myself (It's not 100% accurate):
The default is class definition, if you choose this one. It will
generate that subclass and it will just work. You'll be able to access
your tweets as a class called Tweet. This sounds good. Btw if you do
this it will NOT show up in your file navigator.
The one we choose the most often is the category/extension what this
will do it will only generate an extension of the Tweet class. You
have to actually write the tweet class itself. The extension will take
care of making all the vars. Even when I switch to category/extension
again I don't get that extension showing up in the navigator. It's
kind of hidden from you.
And why do we like this one? Because a lot of times we want to add our
own code. Like in a Tweet, imagine you want to add a static method
that took data from Twitter and turned it into a tweet in the
database. Where would we put code? Well a great place to put that code
would be in the Tweet class...if there was such a thing...and the
extension is going to handle all the var business for you.
If you did choose manual/none for codegen. meaning don't do any
codegen, then you would be doing value/setValue(forKey:)...good luck
with that You're code is going to be a mess. [ie there is no
.propertyName = value ...you'd had to do setValue(value, forKey:
propertyName)].
Long story short, I'm not sure why but for some reason if you don't select the create NSManagedObject subclass then it seems to still work, but without showing what's happening under the hood. Very counter intuitive!
Then also watch this live demo of the Core Data Stanford course:
Now we know we want to access all this stuff not using
value/set(value:forKey:)...we want to have to subclasses of
Users/Tweets. And we want to have vars [ dot notation] for all these
relationships so we need that code to be generate. The way we do that
we just select the entity... and we go down here to CodeGen. This says
by default class definition. That means it's done it. It has generate
a class called Tweet. and It's going to work with var and all
relationships. That's not actually what we want. We want to select
this one [Category/Extension]. Where only create an extension to Tweet
and add the var stuff. That's because we want to write the class
Tweet and put our own code in there. It's very common to write our
own class. But you still want the var magic.
Related
Using Version 8.1 of Xcode.
Create an entity named "MapRegionObject" in .xcdatamodeld file.
Using auto code generator, click Editor on the navigation bar -> create NSManagedOject Subclass...
Got two files : MapRegionObject+CoreDataClass.swift and MapRegionObject+CoreDataProperties
Errors in two files showing in the screenshot:
MapRegionObject+CoreDataClass.swift
MapRegionObject+CoreDataProperties
Please help me fix this bugs, thank you so much!
In Xcode 8.1, before using the auto code generator, you must select the entity in your data model:
Then go to the Data Model Inspector tab:
Under "Codegen" select "Manual/Node"
After that you could create a NSManagedObject subclass without errors.
Alternatively, if you have already used 'Class Definition', you can go into your existing .xcdatamodeld file and set all current entities to 'Manual/None' under Codegen. Make sure to save your project (File -> Save), delete your existing Derived Data, clean the project, and then build. Resolved it for me without having to re-make my whole model.
I found this whole thing to be very confusing. You really do need to understand what's new in CoreData. Basically, the default is to automatically generate the class and the extensions for you in a place called "DerivedData" that's buried in ~/Library/Developer/Xcode/DerivedData where these classes and their extensions live, outside of your code source. Personally, not being able to open and look at them is weird to me, but something to get used it.
Basically, if you have an entity called "AppSettings" in your CoreData model, you can just use it without needing to generate the code yourself. If you want the code in your project, then set the Codegen property on the entity to Manual/None. Then do what you did before: Editor->Create NSManagedObject classes, etc. The files will wind up in your project.
The good news is that if you want to make custom extensions, just do that in your project. Xcode will blend the generated files, from their other place outside your project directory, with the files in your project directory.
1) clean the project (cmd + shift + K)
2) In the "data model inspector" for every created Entity set attributes for Class just as in the screenshot below
3) Generate code again (Editor -> create NSManagedObject Subclasses)
After that everything should work fine.
The problem is that you don't need to generate NSManagedObjectModel subclasses manually anymore.
ref: https://forums.developer.apple.com/thread/48988
Xcode automatically generates classes or class extensions for the
entities and properties in a Core Data data model. Automatic code
generation is enabled and disabled on an entity by entity basis, and
is enabled for all entities in new models using the Xcode 8 file
format. This feature is available for any data model that has been
upgraded to the Xcode 8 format. You specify whether Xcode generates
Swift or Objective-C code for a data model using the data model’s file
inspector. When automatic code generation is enabled for an entity,
Xcode creates either a class or class extension for the entity as
specified in the entity's inspector: the specified class name is used
and the sources are placed in the project’s Derived Data. For both
Swift and Objective-C, these classes are directly usable from the
project’s code. For Objective-C, an additional header file is created
for all generated entities in your model: The file name conforms to
the naming convention 'DataModelName+CoreDataModel.h'.
Close the project and follow the following instructions:
Reveal in finder your database .xcdatamodeld file.
on .xcdatamodeld file right click -> Show Package Contents, if(.xcdatamodel) is find again in the package again right click and 'Show Package Contents'. you should get 'contents' file.
Open 'contents' in text edit.
Command-F (codeGenerationType="class") and replace all matchings string with blank string.
Save and open Xcode project again.Everything should work well.
In Xcode 8.2.1 , Menu-Product-Clean，And every is ok, it's so verid.
Don't fight the with Xcode on this unless you really need to alter your generated properties, doing so will just leave you frustrated.
Think of the auto-generated class as any other class in your application. If you need to add functionality to your managed object class, simply change your class definition into an extension and extend your object.
change your class:
class MyManagedObject : NSManagedObject { /* implementation*/ }
to an extension:
extension MyManagedObject { /* implementation */ }
This isn't an answer. It's just explanation of what's going on with the selections
Make sure you see this moment for the Core Data Stanford course
Below is a transcript I wrote myself (It's not 100% accurate):
The default is class definition, if you choose this one. It will
generate that subclass and it will just work. You'll be able to access
your tweets as a class called Tweet. This sounds good. Btw if you do
this it will NOT show up in your file navigator.
The one we choose the most often is the category/extension what this
will do it will only generate an extension of the Tweet class. You
have to actually write the tweet class itself. The extension will take
care of making all the vars. Even when I switch to category/extension
again I don't get that extension showing up in the navigator. It's
kind of hidden from you.
And why do we like this one? Because a lot of times we want to add our
own code. Like in a Tweet, imagine you want to add a static method
that took data from Twitter and turned it into a tweet in the
database. Where would we put code? Well a great place to put that code
would be in the Tweet class...if there was such a thing...and the
extension is going to handle all the var business for you.
If you did choose manual/none for codegen. meaning don't do any
codegen, then you would be doing value/setValue(forKey:)...good luck
with that You're code is going to be a mess. [ie there is no
.propertyName = value ...you'd had to do setValue(value, forKey:
propertyName)].
Long story short, I'm not sure why but for some reason if you don't select the create NSManagedObject subclass then it seems to still work, but without showing what's happening under the hood. Very counter intuitive!
Then also watch this live demo of the Core Data Stanford course:
Now we know we want to access all this stuff not using
value/set(value:forKey:)...we want to have to subclasses of
Users/Tweets. And we want to have vars [ dot notation] for all these
relationships so we need that code to be generate. The way we do that
we just select the entity... and we go down here to CodeGen. This says
by default class definition. That means it's done it. It has generate
a class called Tweet. and It's going to work with var and all
relationships. That's not actually what we want. We want to select
this one [Category/Extension]. Where only create an extension to Tweet
and add the var stuff. That's because we want to write the class
Tweet and put our own code in there. It's very common to write our
own class. But you still want the var magic.
I am working with CoreData, on an entity called "RoleName".
The problem is: I click on "Create NSManagedObject subclass" from within my model, and so it automatically creates the classes for my entity.
However, on the declaration of the class, I get this error:
Invalid redeclaration of "RoleName"
even though I don't have any other class with the same name.
This is because Xcode handles all that by itself. I felt it like a bit of trouble as the auto generated classes don't have all my properties.
So follow these steps to get this as it used to be:
Delete what ever classes you already made for core data.
Set class.Module as Current Product module
Set Class.codegen as Manual/None
Now select your entity and create NSmanagedobject subclass
You are all set
From Apple : Whats new in Core Data
Xcode automatic subclass generation
Xcode now supports automatic generation of NSManagedObject subclasses in the modeling tool. In the entity inspector:
Manual/None is the default, and previous behavior; in this case you should implement your own subclass or use NSManagedObject.
Category/Extension generates a class extension in a file named like ClassName+CoreDataGeneratedProperties. You need to
declare/implement the main class (if in Obj-C, via a header the
extension can import named ClassName.h).
Class Definition generates subclass files named like ClassName+CoreDataClass as well as the files generated for
Category/Extension.
The generated files are placed in DerivedData and rebuilt on the first build after the model is saved. They are also indexed by Xcode,
so command-clicking on references and fast-opening by filename works.
You don't need to manually create subclasses for NSManagedObjects.
I would suggest that you delete the files that you created with NSManagedObjects (Move them to Trash) and go to every entity in the DataModel Inspector under Codegen select : Manual / None and create than the Subclasses.
OK, so I read that in Swift, we need to prefix our Core Data entity class names in the inspector with our project namespace.
Let's assume my project is called "MyProject", so for each on my Core Data entity in DataModel.xcdatamodeld I add "MyProject":
MyProject.Book
MyProject.Library
When I select the two entities in the Data Model interface builder and go
Editor > Create NSManagedObject Subclass
It only generated 1 class file called MyProject instead of the usual
Book class
Library class
That's how I normally do it with Objective C.
Is there an extra step with Swift that I'm not aware of ?
Looks like a bug in Xcode that Apple needs to fix as mentioned in the comments of this Stackoverflow post by Martin R:
Unable to find specific subclass of NSManagedObject
A PITA work around
I was reading this
http://jamesonquave.com/blog/core-data-in-swift-tutorial-part-1/
It seems like the way to work around this for now is to:
Before generating NSManagedObject subclass using using Editor, remove all the namespace prefix from entity class name
Select all the entities you want to generate NSManagedObject subclass for and generate them using Editor
Now add the namespace prefix back to all the entity class name and save the data model file.
Have to wait for Apple to fix it I guess =/
I'm creating a todo app:
I created an entity in my projects .datamodel file, I added the entity an attribute of a string called "content" and created NSManagedObject subclass with the "editor" > "Create NSManagedObject subclass:
This class was created:
#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>
#interface Targets : NSManagedObject
#property (nonatomic, retain) NSString * content;
#end
but now I want another "id" attribute to do I can give each todo an id...
How should I do this? is it ok to do it manually? since I generated it from the entity model it feels like I need to create a new entity to do that...?
If you can direct me, and maybe through an explanation how that works it would be awesome..maybe I dont understand something here and this is why I'm asking this question
In light of the fact that Xcode appears to have a bug which prevents it from appropriately replacing your CoreData files, I've rewritten my answer with a workaround.
Delete the originally generated class file:
(Click move to trash.)
Add the attribute:
Generate the class in the exact manner you generated the original we deleted in step 1:
So, the solution to your problem is actually quite simple:
To add another attribute to your entity, you can just approach it exactly in the same way as you did with the content attribute. Just add the attribute within the graphical editor, just like you did before with content, and then again, use Xcode's built-in functionality to generate the classes, in the same way as you did before.
What will happen is that Xcode overrides the formerly generated files, and replaces them with a new version that now has the attributes. There is no harm in doing that process as often as you like. :)
EDIT:
Short side note, you need to remember to delete the app from your device (or the simulator) after you changed the data model, because otherwise the app will crash because your new Core Data model is not consistent with the one you used before.
Second, if you want to add functionality to your data model classes (which you should do with much care anyway, but maybe some utility Core Data functions or so...), you should make use of iOS categories, so that the code which you wrote for that doesn't get deleted when you regenerate your model classes. The Stanford Lecture on iOS development has a great introduction session on Core Data where this approach is explained in detail!
I have some doubts regarding storing plain "int" or "short" (int16_t) attributes inside the "Core Data" data management framework (on iOS 6 in my case).
I tried using it various ways and found it impossible to do, failing with the above mentioned exception. Now, a few weeks later, I found this article inside StackOverflow and it looks like someone does exactly that:
See following example for storing an Enumeration in the lower answer from "Daniel Eggert":
Best way to implement Enums with Core Data
Here it looks as if he uses a plain "int16_t" and maps it to a "Core Data" entry "Integer 16" inside the data model... does this really work? I tried it exactly as stated (even using the same naming :-)) and it fails with the well known "EXC_BAD_ACCESS" exception... as expected.
Any thoughts on this one? Did I misinterpret the linked answer?
---- Edit: ---
Interesting how someone rates this question (that even properly links another question) down, but doesn't have an answer?! Anyway:
I now tried the very same with the "Event" sample application from Apple and it works.
My own test doesn't work, still. Main difference between the apps:
My managed class is not auto-generated, I reused an existing class
I still have some properties with "#synthesize" in my existing class
My own entity (managed object):
h:
#interface TestEntity : NSManagedObject
{
}
#property (nonatomic) int64_t testAttribute;
#end
m:
#dynamic testAttribute;
model data type: "Integer 64".
other.m:
TestEntity *testEntity = (TestEntity *)[NSEntityDescription insertNewObjectForEntityForName:#"Trip" inManagedObjectContext:[GenericDAO getManagedContext]];
[testEntity setTestAttribute : 4]; //this triggers the exception
After going into detail with the whole issue the last week, I found out that using iOS 6 and the latest XCode (4.6.2 in my case) I can do everything exactly as specified in the link mentioned in my question. The issues I have seen are related to a set of technical details that are simply not documented. How did I find out about it? I simply did the following steps to validate my entities:
Create a new empty project with Xcode that support Core Data
Use the "editor" menu item "import" when being in Xcode, having the data model open (select the "XY.xcdatamodeld" you want to use with Core-Data.
You will see which items are imported in your model and which are "incorrectly" specified (either by property settings or else)
Now simply create all attributes you originally wanted to have coded as primitive data types, and select the "export" menu item inside the "editor" menu (when data model is selected!). Careful: check the "create primitive data type" check box to get base-types instead of Cocoa/object properties.
To check back your original project, do this also in the original project, in my case Core-Data and even the menu items looked differently (some options are greyed-out):
Do the same steps (importing entities into the data model) in old/your current project.
If the result is different, this will tell you that your project settings are somehow incompatible/old and you can go change the project settings to find out which ones impact the Core Data behavior.
Also try to use the export function to see if it generates the code correctly.
Other important tip: you can select the attributes in the Core-Data data-model editor and copy/paste them between projects.. This comes very handy if you want to migrate some entities/properties for testing. Do not just copy over the whole "cxdatamodeld" settings file, it keeps its settings from the old project (I tried it two times to validate that).
Check you set the Name, Class and Parent Entity correctly for all the entities in your Core Data Model file. Check all your class names match your entity names. The reason for the problem is when compiling the model it doesn't find the header file with the setter.