R – Is it possible to store an NSMutableArray together with all its contents into a file and restore it later from there

iphonepersistence

Some kind of serialization available in iPhone OS? Is that practically possible or should I quickly forget about that?

I am making a tiny app that stores some inputs in an NSMutableArray. When the user leaves, the inputs should stay alive until he/she returns to continue adding or removing stuff to/from that array.

When the app quits, there must be some way to store all the stuff in the array in a file. Or must I iterate over it, rip everything out and write it i.e. comma-separated somewhere, then the next time go in again, read the stuff in, and iterate over the lines in the file to make an array with that data? That would be hard like a brick. How to?

Best Solution

The easy way, since you already have an NSArray object is to write the array to disk using

- (BOOL)writeToFile:(NSString *)path atomically:(BOOL)flag

and read it back in with:

- (id)initWithContentsOfFile:(NSString *)aPath

+ (id)arrayWithContentsOfFile:(NSString *)aPath

You can also use NSCoder.

You can probably search sof for the right code.

Related Solutions

R – Besides sqlite3, CoreData and NSUserDefaults, what are the most easy to handle data persistance techniques in iPhone OS

Have a look at NSKeyedArchiver/Unarchiver. As long as everything in your array conforms to the NSCoding protocol (NSStrings and NSNumbers already do) you can just save your array to disk like this:

NSData *data = [NSKeyedArchiver archivedDataWithRootObject:myArray];
[data writeToFile:@"/a/path/to/myFile" atomically:YES];

You can load it back like this:

NSData *data = [NSData dataWithContentsOfFile:@"/a/path/to/myFile"];
NSArray *myArray = [NSKeyedUnarchiver unarchiveObjectWithData:data];

This method is simple and easy for simple applications such as yours.

IOS app update, how to update plist in the bundle

You can't update anything that's part of the bundle. Save the plist in the documents directory if you want to be able to update it.

NSArray *arrayPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
        NSUserDomainMask, YES);
NSString *documentsDirectory = [arrayPaths objectAtIndex:0];

Files in the documents directory don't get deleted when updating an app using the store.

Best Solution

Related Solutions

R – Besides sqlite3, CoreData and NSUserDefaults, what are the most easy to handle data persistance techniques in iPhone OS

IOS app update, how to update plist in the bundle

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