In my application (iOS 5) I want to save data - I want to save debts.
So its:
plus or minus money
the amount of money
and the name who has the debts (or the name where you have the debts)
But I don't how to save the data (NSUserdefaults,Core data, SQLLite)
Maybe you can tell me the best way to save them?
The easiest way to store small amount of data on your device is to use NSUserDefaults. But only property lists could be saved in this way. A property list is a combination of objects of 6 types, NSNumber, NSString, NSArray, NSDictionary, NSDate, NSData.
In your case it's easy to do. For example, to save a new debt record you can use following method:
#define DEBTS_LIST_KEY #"listOfAllDebts"
#define DEBTOR_NAME_KEY #"debtorName"
#define DEBT_AMOUNT_KEY #"amountOfDebt"
-(void) saveDebt:(CGFloat) debtAmount forName:(NSString *) debtorName
{
// pointer to standart user defaults
NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults];
// the mutalbe array of all debts
NSMutableArray * alldebtRecords = [[defaults objectForKey:DEBTS_LIST_KEY] mutableCopy];
// create new record
// to save CGFloat you need to wrap it into NSNumber
NSNumber * amount = [NSNumber numberWithFloat:debtAmount];
NSDictionary * newRecord = [NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:amount,debtorName, nil] forKeys:[NSArray arrayWithObjects:DEBT_AMOUNT_KEY, DEBTOR_NAME_KEY, nil]];
[alldebtRecords addObject:newRecord];
[defaults setObject:alldebtRecords forKey:DEBTS_LIST_KEY];
// do not forget to save changes
[defaults synchronize];
}
To readList of debts you have read something similar.
But I recommend you to use core data. It's more flexible and you won't have to write all this code to manage your data (to edit existed records, or to delete them). You will be able to extend your model much easier, for example, when you want to save the date of the debt. This is the link to a good tutorial
If the quantity of records is user-defined, and will grow with app use, I suggest Core Data, which can be backed by SQLite. If you are working in a modern Xcode (i.e. Xcode 4), creating models is easy and graphical. If you have ever worked with ORM frameworks before, the interface for querying, etc. should be easy to grasp.
Search around for some tutorials, but be specific about finding tutorials that match your version of Xcode, as Core Data development has been changing a lot lately.
Good and easy way is to create your own objects and serialize them using NSCodying and NSCopying
https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Protocols/NSCopying_Protocol/Reference/Reference.html
https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Protocols/NSCoding_Protocol/Reference/Reference.html
Related
I'm making an app with a list of the products of a company. The data does not need to be modified by the user. How can I save this information? The data must already exist locally when you download the app.
As per your requirement Plist or SQLite is good option for you.
Why Plist
Because it is lightweight.
Why SQLite
If you want to perform query on your data.
You can save the data in sqlite or coredata. For already filling the data in database you can use "sqlite manager" and run your queries in sqlite manager and save it on desktop(where you want). After create the filled database drag it into your project and do whatever your want. You have already filled database here.
You can go with either NSUserdefaults or CoreData, additionally there is a third party library called Realm.
Also check this question:
storing data locally on the iphone
Edit
The answer was provided by Sr.Richie in the link:
For simple data you should use NSUserDefaults. CoreData is very cool but mainly to store DB structures, and introduces complexity (but i love it:)). If you just need to store String, Array and so on (basically prefs), you can go with NSUserDefaults:
For example:
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults]; //load NSUserDefaults
NSArray *fakeFavs = [[ NSArray alloc] initWithObjects:#"2",#"4", #"100", nil]; //declare array to be stored in NSUserDefaults
[prefs setObject:fakeFavs forKey:#"favourites"]; //set the prev Array for key value "favourites"
I am new to cObject or App world, I'm about to make an app where I need to store some information on some players (football), but I do not know where to store them and will hear what you think is best ?
I need to store data like name, age, etc.. I know how I'm doing some text boxes so I can enter the data, but do not know where to save it, I can read that I can use the plist and SQLite, so my quest is if I have about 16-20 names and should only used em on the device where the data have been saved and where I can edit and deleted them, what would you recommend to use as a data source ! or would you recommend another approach ?
Im coding in Xcode atm.
I would suggest you to use CoreDataModel. CoreDataModel is a data storage model for Objective C. It's the way faster then SQL databases and similar to in terms of creating tables, making table connections. You can find more information in Ray Wenderlich's Tutorial.
Since you data model would include many attributes (name, age, etc.), or even relational models I would not suggest using plists in your case.
you can use NSUserDefaults if the data you want to store is very small.
Lets say you have an array of users
NSArray *users = ,,,,,;
to save it
[[NSUSerDefaults standardUserDefaults] setObject:users forKey:#"myKey"];
For later to get users data,
NSARray *users = [[NSUSerDefaults standardUserDefaults] objectForKey:#"myKey"];
What kind of database do you suggest? I want to store user email, username, password, and a couple other random pieces of information. It doesn't have to be fancy. Just a simple database. Are there any free options?
The user information needs to be stored in the keychain to keep it secure.
Any other information could be stored in any one of:
User defaults NSUserDefaults
File on disk (maybe a plist)
Database Core Data (technically just a file on disk)
Which you choose depends on what the data is, how much there is and what kind of access you need to it.
If your data is small and chosen by the user as some kind of setting then user defaults makes sense and is the lowest cost for you to implement.
To use a database, check out Core Data intro.
Wain is right but I think as you want to store small amount of data for further use, the most efficient ways is to use NSUserDefault.
NSUserDefault stores data in NSDictionary type things.
I think this is the step you have to take:
1- check if data exists. I mean if user selected the number if the last run of your app. So in viewDidLoad method:
NSMutableDictionary *userDefaultDataDictionary = [[[NSUserDefaults standardUserDefaults] dictionaryForKey:ALL_DATA_KEY] mutableCopy];
if (userDefaultDataDictionary) {
// so the dictionary exists, which means user has entered the number in previous app run
// and you can read it from the NSDictionaty:
if(userDefaultDataDictionary[LABLE_KEY]){
//and store it
}
}
2 - you can implement some method like syncronize to store data in NSUserDefault every time something has been changed.
- (void) synchronize
{
NSMutableDictionary *dictionaryForUserDefault = [[[NSUserDefaults standardUserDefaults] dictionaryForKey:ALL_DATA_KEY] mutableCopy];
if(!dictionaryForUserDefault)
dictionaryForUserDefault = [[NSMutableDictionary alloc] init];
dictionaryForUserDefault[LABLE_KEY] = //data you want to store
[[NSUserDefaults standardUserDefaults] setObject:dictionaryForUserDefault forKey:ALL_DATA_KEY];
[[NSUserDefaults standardUserDefaults] synchronize];
}
P.S. and don't forget to #define your keys for your dictionary:
#define LABLE_KEY #"Lables"
#define ALL_DATA_KEY #"AllData"
Store it in a plist. If you're talking about data pertaining to one or a few users, that's probably the easy thing. here is a simple example.
Since you say database, store in Sqlite. There's some provided stuff for it already in xcode.
The entire database is contained in one file, which can be moved around if you need to.
Here is some more information on how to use one in your app.
I'm trying to add an array of uiviews to NSDefault but it doesn't seem to be keep the array. Does any one know why? I also tried to store each view in nsvalue before storing it in nsdefault which still didn't work.
NSArray *arr = [[NSArray alloc] initWithObjects:[NSValue valueWithNonretainedObject:myView], nil]];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:arr forKey:#"myKey"];
NSArray *resultArray = [defaults objectForKey:#"myKey"];
and resultArray is nil!
Thanks
the reason why I'm trying to do this is because these are the header views of my uitableview. Since it takes time to create them I wanted to create them only once and store them for future access.
From the docs for NSUserDefaults:
The NSUserDefaults class provides convenience methods for accessing common types such as floats, doubles, integers, Booleans, and URLs. A default object must be a property list, that is, an instance of (or for collections a combination of instances of): NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary. If you want to store any other type of object, you should typically archive it to create an instance of NSData. For more details, see Preferences and Settings Programming Guide.
If you want to put a UIView (why?) in NSUserDefaults, you need to archive it first into an NSData object.
But you need to ask yourself why you want to put a view in NSUserDefaults. You should only be putting bits of data in NSUserDefaults. Views display data. It's easy to redisplay a view once you have the data back. Consider just putting some needed data in NSUserDefaults.
Are you sure you want to do that? It is definitely better to store an array of models to the data base or some file and recreate views from them when needed.
A ha! You are not the first person to face this issue. I've not had this type of issue myself but, in the link below, is a blog with code that allows you to cache and re-use your views. Then you would only need to re-create the views when you launch. Example code:
Cache UIViews for re-use in tableview
I was wondering if there is a way to store small amounts of data, without going to a full-blown core-data API. I just need to store 6 'double' values somewhere... What's the best approach for that?
Thanks, Alex.
Core Data is just one way to store data, and it only makes sense when you need the things that it does. Here are five good options for storing your data:
Use NSUserDefaults. (Dead simple.)
Store the data in an appropriate structure (say, NSDictionary) and store it as a property list. (Pretty darn easy.)
Store the data in a class of your own design that implements NSCoding, and then write an instance of that class to a file using NSKeyedArchiver. (Works well for storing entire object graphs; this is basically what IB does. It might take an hour or two for the light to come on, but once you understand it this is a very nice way to read and write objects.)
Use Cocoa Touch's file system API, notably NSFileHandle and NSFileManager. (Conceptually simple if you've ever worked with a file system before. Puts you in complete control.)
Use the regular old POSIX file system API. (Best for existing Unix code, or code that you also want to compile on other platforms.)
Before you jump into any of those, read Apple's Archives and Serializations Programming Guide, User Defaults Programming Topics, and File System Programming Guide.
You can use NSUserDefaults to accomplish that (http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSUserDefaults_Class/Reference/Reference.html).
-(void)saveToUserDefaults:(NSString*)myString
{
NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];
if (standardUserDefaults) {
[standardUserDefaults setObject:myString forKey:#"Prefs"];
[standardUserDefaults synchronize];
}
}
-(NSString*)retrieveFromUserDefaults
{
NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];
NSString *val = nil;
if (standardUserDefaults)
val = [standardUserDefaults objectForKey:#"Prefs"];
return val;
}
The easiest way to store small amounts of data without using some of the larger API's is the NSUserDefaults class. It's really easy to set up and use.