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.
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.
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.
any recommendations for saving four strings into an own file format that is read by the application and can be shared?
In my app, you will be able to enter some text in some boxes and the app shows a view with an background image and those strings. Now, I am already able to save this as a picture, but I actually want to save it to an own file format so that you can save different files that can be modified afterwards as well or even exchanged via email and opened from another iphone with the app.
Now, I wrote the code for accessing the documents folder of the app, as well as saving and deleting. Thing is, i dont know how to store those strings in a file (perhaps in a xml?) and read them easily afterwards from my application.
For the exchanging part, I found that link which would be a nice feature indeed: http://iosdevelopertips.com/cocoa/launching-your-own-application-via-a-custom-url-scheme.html
Parsing xml seems not that difficult (never done it before): http://ipad.about.com/od/iPad-App-Dev/a/How-To-Parse-Xml-Files-In-Xcode-Objective-C.htm
If it's only a small bit of infomation then the easiest way to store your data in a file would be using a plist - there's a good tutorial here - http://www.icodeblog.com/2009/02/14/loading-data-from-plist-files/
In addition to the plist, you could also do the following approaches:
1) simplest - open a file in your documents directory, write the 4 strings (using whatever delimiter/end of string marker is useful - carriage return?) and overwrite them each time through. (i.e. it's your file, you can format it how you like)
2) mildly harder - use Apple's NSArchive to pack and unpack the strings.
3) possible overkill - store them directly in a SQLite database
4) major overkill - store them in CoreData.
Of course, the "overkill" options also provide you with extra features which may be of use if your app functionality extends beyond what you've outlined.
By sharing, I would think that simple copy and paste might be enough, but there's also sending it via email, or tripping another app's URL scheme to make it open it and sending the strings as part of the URL. You'd have to know that the other app would be able to interpret your strings as part of the URL, so you might have to write it yourself.
Okay guys I found that very nice method in the NSString documentation:
–writeToFile:atomically:encoding:error:
I think I am gonna separate my strings by /n and save them to a .txt. When I am gonna read the file afterwards, i am getting the string, divide it to substrings. That will do it, I guess.
One last question: Is it possible to replace the content of my file so that I won't need to create a new file every time i want to change something?
Thanks!
In my iPhone / iPad application, I show a person's medical reports in the form of a PDF. I have saved the reports in the documents directory and am reading them from there.
I want the user to be able to add or edit comments on these PDFs, as well as be able to highlight certain sections in the PDF. After editing, the application should be able to save the PDF back into the documents directory.
Is this possible within an iOS application? If so, how? Is this a task for Core Graphics?
Editing PDF directly on iPad/iPhone is a rather big job because the standard API only supports showing it (and only a bit more.) If you want to do anything more, you need to invest a huge amount of time to implement generic pdf handling code.
There is an open-source library handling these, e.g. this one. I don't know if it fits your needs, though.
A better idea, in my opinion, is to create a native UI showing the data contained in the PDF file using the standard Cocoa-Touch UIKit and create the PDF once the user is done with it so that the user can export it back. That way, you don't have to write a complicated PDF handling code.
In any case, it's not a good idea to show generic PDF on iPhone, because the screen size is so small (iPad is a different question, especially if you expect the user to be familiar with the particular format of your pdf.). A dedicated UI would be much better.
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.