My information in a plist isn't saved - iphone

Question

I have some settings in a plist, but when I kill my app I lose all the data stored there.
This is the code that I'm using:
.h
#property (retain, nonatomic) NSString *plistFilePath;
-(IBAction)setHomepage:(id)sender;
.m
#syntehzise plistFilePath;
-(IBAction)setHomepage:(id)sender{
plistFilePath = [NSString stringWithString:[[NSBundle mainBundle] pathForResource:#"settings" ofType:#"plist"]];
NSMutableDictionary *data= [[NSMutableDictionary alloc] initWithContentsOfFile:plistFilePath];
[data setObject:#"http://www.google.com" forKey:#"Homepage"];
[data writeToFile:plistFilePath atomically:YES];
[data release];
}
Am I doing something wrong? Should I use a different class or differents methods? Please help me because I don't know why I store well the information but then when I kill the app I lose it.

Answer 1

As already mentioned the bundle is read only.
Try to avoid setting 'settings' in an a copied plist, as plists are just one more thing to managed. Instead, why not use NSUserDefaults and import your defaults from a defaults plist. For example, add a new plist to your project, and add this to your delegate:
// Get the shared defaults object
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
// Register the defaults each time the app loads
NSString *defaultsFile = [[NSBundle mainBundle] pathForResource:#"Defaults" ofType:#"plist"];
NSDictionary *defaultsDict = [NSDictionary dictionaryWithContentsOfFile:defaultsFile];
[defaults registerDefaults:defaultsDict];
Now you can save data like this:
// Store the data
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:#"http://mattmelton.co.uk" forKey:#"HomePage"];
[defaults synchronize];
And retrieve it like this:
// Retrieve data
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSString *homePage = [defaults objectForKey:#"HomePage"];
And you don't have to worry about external files. Naturally your defaults plist can be platform, user or device specific!
Hope this helps!

Answer 2

The application bundle is readonly. If you want to distribute a file and then update it, move it from the bundle to the documents folder the first time your application runs.