How to use pList in iOS Programming - iphone

Question

Recently, I'm a senior in high school, and I'm interested in making apps for iPhone. Recently, one of my apps came out: NBlock. It's a puzzle app and it's very challenging. However, it has a few problems. The high scores are not saved. I've been told to use a plist. Any tips?

Answer 1

The URL based method for this:
// Get the URL for the document directory
NSFileManager *fileManager = [[NSFileManager alloc] init];
NSURL *documentDirectoryURL = [[fileManager URLsForDocumentDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] objectAtIndex:0];
// Turn the filename into a string safe for use in a URL
NSString *safeString = [#"scores.plist" stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
// Create an array for the score
NSMutableArray *array = [[NSMutableArray alloc] init];
[array addObject:[NSNumber numberWithInt:score]];
// Write this array to a URL
NSURL *arrayURL = [NSURL URLWithString:safeString relativeToURL:documentDirectoryURL];
[array writeToURL:arrayURL atomically:YES];

Answer 2

I'd avoid using a plist. The easiest way to save simple data in an application, by far, is NSUserDefaults.
Check out this tutorial for a simple guide on how to use NSUserDefaults. Always be sure to synchronize NSUserDefaults when you're done writing to them.
If you're looking for a more powerful (but more complex) way to save data, check out Apple's guide to using Core Data.

Answer 3

Heres what you want:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent:#"scores.plist"];
NSMutableArray *array = [[NSMutableArray alloc] init];      
[array addObject:[NSNumber numberWithInt:score]];        
[array writeToFile:path atomically:YES];
And to add new scores do initWithContentsOfFile:#"scores.plist" instead of init in the declaration of array. You can optionally use NSUserDefaults.

Answer 4

Take a look into NSKeyedArchiver/Unarchiver. You can save pretty much anything you want; NSUserDefaults, in my experience, dumps your data if you kill your app from the tray. Core data is really used better if you're managing large amounts of data with databases such as sqlite.

Answer 5

I would say the below code will work and pretty straight forward unless custom object data types(Its a different story again) are used:
NSString* plistPath = nil;
NSFileManager* manager = [NSFileManager defaultManager];
if ((plistPath = [[[NSBundle mainBundle] bundlePath] stringByAppendingPathComponent:#"PathTo.plist"]))
{
if ([manager isWritableFileAtPath:plistPath])
{
NSMutableDictionary* infoDict = [NSMutableDictionary dictionaryWithContentsOfFile:plistPath];
[infoDict setObject:#"foo object" forKey:#"fookey"];
[infoDict writeToFile:plistPath atomically:NO];
[manager setAttributes:[NSDictionary dictionaryWithObject:[NSDate date] forKey:NSFileModificationDate] ofItemAtPath:[[NSBundle mainBundle] bundlePath] error:nil];
}
}
setting the date attribute might be helpful to check when is the last time score was updated.