Error while checking if a file exists - objective-c

Question

I'm trying to write to a plist file using writeToFile, before I write I check whether the file exists.
This is the code:
#import "WindowController.h"
#implementation WindowController
#synthesize contacts;
NSString *filePath;
NSFileManager *fileManager;
- (IBAction)addContactAction:(id)sender {
NSDictionary *dict =[NSDictionary dictionaryWithObjectsAndKeys:
[txtFirstName stringValue], #"firstName",
[txtLastName stringValue], #"lastName",
[txtPhoneNumber stringValue], #"phoneNumber",
nil];
[arrayContacts addObject:dict];
[self updateFile];
}
- (void)awakeFromNib {
NSString *rootPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
filePath = [rootPath stringByAppendingPathComponent:#"Contacts.plist"];
fileManager = [NSFileManager defaultManager];
contacts = [[NSMutableArray alloc] init];
if ([fileManager fileExistsAtPath:filePath]) {
NSMutableArray *contactsFile = [[NSMutableArray alloc] initWithContentsOfFile:filePath];
for (id contact in contactsFile) {
[arrayContacts addObject:contact];
}
}
}
- (void) updateFile {
if ( ![fileManager fileExistsAtPath:filePath] || [fileManager isWritableFileAtPath:filePath]) {
[[arrayContacts arrangedObjects] writeToFile:filePath atomically:YES];
}
}
#end
When the addContactAction is executed I don't get any error but the program halts and it brings me to the debugger. When I press continue in the debugger I get:
Program received signal: “EXC_BAD_ACCESS”.
But that's probably not important.
PS: I'm new to mac programming and I don't know what else to try since I don't get an error message that tells me what's going wrong.
The path to the file is:
/Users/andre/Documents/Contacts.plist
I earlier tried this(with the same result), but I read that you can only write to the documents folder:
/Users/andre/Desktop/NN/NSTableView/build/Debug/NSTableView.app/Contents/Resources/Contacts.plist
Does anyone have an idea or even an explanation why this happens?

Answer 1

First, I think you shouldn't instantiate an NSFileManager object. Instead you use the default file manager, like this:
[[NSFileManager defaultManager] fileExistsAtPath: filePath];
Then, could you specify at which line the program is breaking into the debugger?

Answer 2

You are setting filePath with the stringByAppendingPathComponent: method. That method returns an autoreleased object. (Autoreleased object is used after it has been (automatically) released, which could cause the bad access error.)
I think changing
[rootPath stringByAppendingPathComponent:#"Contacts.plist"];
into
[[rootPath stringByAppendingPathComponent:#"Contacts.plist"] retain];
will solve your troubles.