retaining plist but loosing plist values - iphone

Question

I am creating a plist to save some values, however during testing I have noted that I retain my newly created plist after the application is closed & removed from multitasking. However I loose my values inside that plist if the application is removed from multitasking but not if the app is closed...
This is the save data method I have in my plist controller class thats managing all of the read/write/save etc.
- (void) saveData:(NSString *)methodName signature:(NSString *)pSignature Version:(NSNumber *)pVersion request:(NSNumber *)rNumber dataVersion:(NSNumber *)dvReturned cacheValue:(NSNumber *)cValue;
{
// get paths from root direcory
NSArray *paths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES);
// get documents path
NSString *documentsPath = [paths objectAtIndex:0];
// get the path to our Data/plist file
NSString *plistPath = [documentsPath stringByAppendingPathComponent:#"EngineProperties.plist"];
// set the variables to the values in the text fields
self.signature = pSignature;
self.version = pVersion;
self.request = rNumber;
self.dataVersion = dvReturned;
//do some if statment stuff here to put the cache in the right place or what have you.
if (methodName == #"manu")
{
self.man = cValue;
}
else if (methodName == #"models")
{
self.mod = cValue;
}
else if (methodName == #"subMod")
{
self.sub = cValue;
}
self.cacheValue = [NSDictionary dictionaryWithObjectsAndKeys:
man, #"Manu",
mod, #"Models",
sub, #"SubModels", nil];
NSDictionary *plistDict = [NSDictionary dictionaryWithObjectsAndKeys:
signature, #"Signature",
version, #"Version",
request, #"Request",
dataVersion, #"Data Version",
cacheValue, #"Cache Value", nil];
NSString *error = nil;
// create NSData from dictionary
NSData *plistData = [NSPropertyListSerialization dataFromPropertyList:plistDict format:NSPropertyListXMLFormat_v1_0 errorDescription:&error];
// check is plistData exists
if(plistData)
{
// write plistData to our Data.plist file
[plistData writeToFile:plistPath atomically:YES];
NSString *myString = [[NSString alloc] initWithData:plistData encoding:NSUTF8StringEncoding];
// NSLog(#"%#", myString);
}
else
{
NSLog(#"Error in saveData: %#", error);
// [error release];
}
}
#end
My question has two parts..
Can I save the values so they are retained in the plist even when the app is removed from the multitaksing bar.
what do I need to change to get this to work if it can work?

Answer 1

This probably has to do with where the saveData method is being called. Check out the app delegate, there are a few stubs in the by default. You probably want applicationWillResignActive, applicationDidEnterBackground or applicationWillTerminate. Check the documentation for each, the one you want will depend on when you want the data to be written.