I'm working on my first osx App and I want to save arrays of objects that I've created on a "project file" like you do in any program when using the "save" button.
I have been looking different ways to do it, Core Data, Document based app, but, I'm not sure how it works any of them to choose the best option for my app.
I want to save arrays of objects that have inside more arrays and other strings and doubles that contain information of the app that the user added. ( It can be a lot of data ) So for that reason I think Userdefault is not a good idea.
I also want to make the app able to open one of this projects saved.
So, could you help me to find which is the best way to do it?
I can suggest you to read iOS FileSystem Overview.
You must use the Data container to locate your local files. For this, you have to locate the NSDocumentDirectory with the NSUserDomainMask (call to NSSearchPathForDirectoriesInDomains) and use standard NSFileManager class.
Related
I'm developing an app that I want the user to be able to take a screenshot with a button (this works, but it's stored to camera roll). I have a need to keep history of these screenshots along with site name, etc.
I've been reading that it's not recommended to save binary data in a sqlite db, so I've stumbled across core data. I'm still learning, but one question that comes to mind is this. Some recommend to save the filename to coredata and then save the image to document directory. I want to read the data back into a table view controller and have the image part of the cell. Will I need to resize the image to the size I want when reading in, or will it automatically size down to what it needs?
Also, when saving to document directory, are those files accessible from the camera roll? I don't want them to be and I'd like to give the user the ability to be able to delete them with the tableviewcontroller.
Please let me know if I need to expand on anything. I'm learning Swift, so I'm sure I missed something.
You should not save it to the Documents directory.
You should instead Allow External Storage of the attribute. Core Data will take care of storing it for you. This is explained in the answer by jansenmaarten to this question.
How does this sound conceptually.
I wanted to store some text and add tags to it thats easily retrivable. Coredata is the obvious solution, but i also needed that data across the cloud, not just iCloud like dropbox. So I thot i'd use Coredata + textFiles.
obvious approach
use coredata with two entities. One for text and one for tags. Works awesome BUT not ready for syncing.
1. using icloud coredata combo will hurt me badly, its still unreliable, and i cant afford to keep stabilising it.
2. i dont just have ios devices, need it on my computer too.
the solution
Add text in a simple textview.
Add tags to the text as well using some kinda delimiters.
Save the document as a text file (that includes tags) and give the document some unique name
Put that file in dropbox or icloud or whatever as a document But Also, parse it locally in the iOS app so that the text in file is separated into text and tags each of which enters its entity in coredata.
advantage for the solution
I can use the text in a useful way locally (in iphone) and if needed will get those text files from the cloud.
problem with the solution
Data in the cloud (as textfiles) is only so useful. But nonetheless, its there, i can live with this.
SYNCING: how do i make sure that each file is synced appropriately. Im not sure I should use UIManagedDocument? I'm already using coredata locally, dont know how i'd complicate things if i use UIManagedDocument.
My question is, im confused about the syncing and saving part, what should i do to keep it neat and clean.
While writing this question i feel like I screwed up the whole idea.
OK, I know how to use core data and I know how to populate them from code on Xcode, but how do you guys manage to replicate the same structure on OSX and populate the tables, exporting the final sqlite file to Xcode?
What I mean is this: I want a way to see the same core data structures on OSX and have the ability to populate them with records from comma delimited files, for example, create all the modifications I need and then exporting the sqlite file and the xcdatamodeld file structure to Xcode.
And yes, I know a bunch of apps that enable me to read sqlite files and edit them, but this is not the same thing.
thanks
Sure there is. That is what I have already done. Just make sure you share the same ManagedObjectModel between these two apps. Than you can use your Mac App to populate the database, although I know that CoreData is not a database.
So create a usual CoreData App on the mac or iPhone and make sure you share the same ManagedObjectModel, so copy the file into the app. Then copy the database file from one app to the other and make sure Xcode includes them in the build process.
I want to use a Docset i have created using Doxygen in my iPad app in a tableview, and navigate through the directories. then display the file i click.
How would i go about navigating the Docset? i can unzip it, then navigate the directories in that manner, though i'm certain there must be a way of using the file as is and then being able to run search queries on the database, etc.
Could someone please give me a pointer in the direction i should be looking?
Thank you very much
If you look inside of a docset bundle, there is a compiled .mom file (CoreData) and a couple of plist files (with various extensions). I do not think there is a straightforward way to consume all that data without knowing the schemas.
You should probably create your own core data schema, and index the HTML contents of the docset manually at the first run of your app, and reuse that for searching and such.
i am working on an application that displays read-only data i am shipping.
it is more of a book.
It is easy with SQLite but i am not satisfied with the performance and trying to use Core Data.
The issue is with pre-filling Core Data is that it is a hard process.
My question is:
Is it possible to build an assistant iphone application (for me to use) which uses the same data model for pre-filling.
and then take the populated .xcdatamodel file and use it in my original application?
I hope this makes sense :)
Adham
I believe what you're asking is whether you can create a CoreData database upfront and copy it to the iPhone. Is that correct?
This article will help. Here's a quote:
I thus suggest the following five-step process:
Create your data in a comma-separated file, typically placing each row of data (an entity) in a row of the file and separating different columns (its attributes) by commas.
Write a standalone program and copy in your .xcdatamodel file from your main project.
Write code in your new program that parses your comma-separated file and inserts the information into a Core Data persistent store that should be identical to the persistent store in your main project.
Run the program in the Simulator
Copy your data from the Simulator's documents directory into your actual project's bundle.
It's possible, I've done it. I made a desktop application to read from a CSV file using the code here:
http://www.mac-developer-network.com/columns/coredata/may2009/
I just had to alter the way the CSV part worked, and change the model.
I copied and pasted my model from the model builder into the iPhone model. (Clicked on the "grid" area, selected all, copied)
Then I took the sqlite database the desktop app produced (found it in Application Support, in the folder for this application) and put it into the resources folder
I made some code to copy the sqlite into the documents folder on the iPhone (if it wasn't already there) at startup, in the applicationDidLaunch method. It's possible that having it in the resources folder is no good. Even though you're using the database as read only, Core Data may want to write something to it. Not sure about this though..
I used the sqlite file in the documents folder in my Core Data set up.
The desktop and iPhone Core Data sqlite file seem to be exactly the same format. You can transfer one sqlite file to another application (iPhone to iPhone too) as long as they have the same data model. In another application, I used NSXMLParser to create the Core Data sqlite file, then transferred it to another app, both on iPhone using the Simulator.
Yeah, your data source can be whatever you want it to be. The other suggestions are good ones. Create a managed object model (.xcdatamodel) identical to what you want to use in your app. Read in the data from your file, create a new instance of your managed object and populate it from the file. Then save, and dive into the bundle in the iPhone Simulator and copy it over. This has the added bonus of being in exactly the format you need, with all the helpful metadata. Copy your object model and your managed object classes and you're good to go.
Note, though, if you really intend for it to be read-only, and you're using it at install, it will be installed in your finished app's bundle (under Applications/{SIGNATURE}/Myapp.app). If you intend to edit this database or allow a user to save to it, it's a better idea to copy it to the Applications/{SIGNATURE}/Documents directory where your user database lives.