I'm working on an app where it needs to communicate to a Web Api when it needs to save data. Where would be the best place to save it if wifi/data is not available to send the request? Was thinking NSUSerDefaults, but wasn't sure if this would be the most efficient and secure way?
Let me know your thoughts!
Thanks!
It really depends on type and amount of data you want to save. NSUserDefaults may suffice for small property lists. In case of large amount of data you can use NSFileManager to organise and save your data into files and folders. You may also consider using Core Data if your data can be organised into a database. Choose whichever suits your needs.
Related
I'm working on an iOS app that creates "location sets" where each row contains a location name and a GeoPoint, and each set has its own name. Each of these sets are stored in an object inside our program (all belonging to the same class). Now we want to give users the capability to create sets and upload them to a database, allowing other users to access and download them to their device.
I've been looking in to back-end solutions for work like this, but pretty much everything I've found so far focuses on relational databases and adding and deleting rows and using SQL-like language to retrieve them. Is there a way to store these objects just as objects (and not unpack the info inside to tables), and then retrieve them? It feels like that would be a much simpler way of going about this.
I'm an absolute beginner when it comes to databases, so forgive me if there's info missing here that you would need to help me out. I'll make sure to keep checking back in case someone asks for more info.
Thanks!
Coredata might be useful for you as its based upon the entity. So you can play multiple things around it by using queries (predicates).
But if you just want to save and retrieve back, then as a simplest solution I would suggest to create array/dictionary with entity data, save that into NSUserDefaults so you can retrieve back same while re-launching the app.
Webservices for iOS development:
raywenderlich
icodeblog
WSDL Webservices
Response data parsing, it would be either JSON or XML:
JSON Parsing
XML Parsing
Hope these links would be helpful for you.
I ended up using Parse's mobile back-end service. That was the type of service I was looking for. I've found other similar services since then, like Applilcasa and StackMob, but we're pretty happy with Parse so far.
This is my first time that I am working on a big project for a client. So I was not sure how to solve this problem. However I have come up with two different ideas but I need professionals opinion about which one is better :)
Situation :
There is an application which runs on different client's iPad. Application data is stored by using giant XML file. This XML file is shared among all client by a server. So a server has a centralised copy and each client has their own copy. Once client made changes to their XML copy they updates server copy in and other client updates their copy by updated server copy.
Now only one client can make changes at one time, To fix this I have logic by which before client starts editing XML they need to get ownership from server and server will only allow one client to edit at one time.
Visual Representation :
Now on client side I have to think of a logic by which I will update my client copy and upload it to server. There are two options,
Option 1 :
In option 1, I can directly manipulate XML file by using GDataXML parser and upload that copy to server. For persistence I can save client copy on my iPad in document directory.
Option 2 :
In option 2, I can read XML file create a CoreData representation for local storage. When ever I update data inside core data it will I will change XML file too and than upload that file on server. Double work but I guess better persistence.
Now which one more robust and advisable? Personally I was planning to do option 2 because it seems more robust as I am persisting application data in core data. But option 1 seems more easy work but I don't know how good persistency will remain.
Sorry for lengthy question,
Thanks for any input given.
There are a number of factors which would influence selecting the second option over the first.
How big is the XML file? If you need to work with very large documents, you may need to incrementally parse the XML (SAX) into core data. This will allow you to access the document's contents without loading it all into memory at once.
Do you need to run complex queries in the data? If so, you may be better off using core data fetch predicates, rather than xpath or XSL.
Are you already using core data? Depending on how the XML data is structured, it might be simpler overall to import the data into your existing persistent store.
Otherwise, you can probably make due with parsing the entire document and either traversing the resulting tree or querying with xpath.
If you need to create an object graph based on what you get from server and show it to user (which you most probably need to do), you should stick up to second option, since it allows easy and robust data persistence.
If you do not need to present user with any data from the XML file you can, of course, store it in the Documents directory.
So, if this is a client application and it has at least some visual representation of the data from an XML file you should use CoreData.
If you want a regular update of data , then use CoreData
Usually I populate my core data with data from internet.
But say I want to prepopulate it with data without downloading it from internet.
Say I want to store all cities, or all tags first.
What would be the standard way to do so?
Should I store the cities on plist?
Should I hardcode inserting all data?
Should I set a variable in coredata to tell whether it has been initialized or not?
What do you guys do?
If it's a lot of data, the fastest way is to provide a populated store. Assuming you're using a sqlite database, you can simply use the Simulator to generate it once, and then put that in your app.
If it's a small amount of data, I'd insert the data at first start, while reading it from some form of xml, csv, or even hardcoded (script-generated) insert statements. It all depends on the situation.
When using Core Data not read-only, you should copy the database to a place where you're allowed to write, when the app starts for the first time. In a read only situation, you can just use the database from the bundle.
I'm pretty new to Core Data, and I'm trying to wrap my head around it.
You might have cases where you want different types of data stored in different places or with different behaviors. For example you might have one read only sqlite store shipped as part of your app containing some default data, an additional store for updates to that data set you have downloaded from a server, and a third for user data. Alternately you might have a case where you want some objects to be persisted while others can live in an in-memory store and do not need to be saved between uses of the app.
I would like to ask you how can i implement the next:
I have a tabBar where each tab make one different connection to one web service, and should show a different data.
I would like to save this data "somewhere" and from it place load the different tabs.
Where i should save this received data?
Thank you,
Best regards
it depends, do you want it to persist across application invocations? If so you best bet is either an sql3lite db or a file on the filesystem (Core Data is another option, although it would seem to be overkill in this case). Both are fairly easy to do. The apple iphone developers portal has examples of both.