viewDidLoad using Persistence - iphone

Question

I have problem with my Iphone project in viewDidLoad event the app crash on
NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
I am trying to store information from text Filed can someone help me to solve the problem
- (void)viewDidLoad{
NSString *filePath = [self dataFilePath];
if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
NSArray *array = [[NSArray alloc] initWithContentsOfFile:filePath];
for (int i = 0; i < 2; i++) {
UITextField *theField = self.lineFields[i];
theField.text = array[i];
}
NSData *data = [[NSMutableData alloc]
initWithContentsOfFile:filePath];
NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc]
initForReadingWithData:data];
BIDThreeLines *threelines = [unarchiver decodeObjectForKey:kRootKey];
[unarchiver finishDecoding];
for (int i = 0; i < 2; i++) {
UITextField *theField = self.lineFields[i];
theField.text = threelines.lines[i];
}
}
UIApplication *app = [UIApplication sharedApplication];
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:#selector(applicationWillResignActive:)
name:UIApplicationWillResignActiveNotification
object:app];
}
Error
2013-03-25 23:29:45.592 MobilePaymentsApp[1182:c07] -[__NSCFArray objectForKey:]: unrecognized selector sent to instance 0x8d0e8d0
2013-03-25 23:29:45.593 MobilePaymentsApp[1182:c07] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFArray objectForKey:]: unrecognized selector sent to instance 0x8d0e8d0'
*** First throw call stack:
(0x1c96012 0x10d3e7e 0x1d214bd 0x1c85bbc 0x1c8594e 0x1c0ae18 0xb030e8 0x339c 0xf91c7 0xf9232 0x483d5 0x4876f 0x48905 0x51917 0x2cc5 0x15157 0x15747 0x1694b 0x27cb5 0x28beb 0x1a698 0x1bf1df9 0x1bf1ad0 0x1c0bbf5 0x1c0b962 0x1c3cbb6 0x1c3bf44 0x1c3be1b 0x1617a 0x17ffc 0x29fd 0x2925)
libc++abi.dylib: terminate called throwing an exception
(lldb)
https://github.com/a-elnajjar/MobilePaymentsApp

Answer 1

NSKeyedArchiver returns object that you have stored in it. eg. if you have stored an array then it will return an array. so be careful while unarchiveing objects.
in following example i have read an array from NSKeyedUnarchiver.
NSData *data = [[NSMutableData alloc] initWithContentsOfFile:filePath];
NSArray *arr = [NSKeyedUnarchiver unarchiveObjectWithData:data];

Answer 2

Look in the crash log's stack trace to see where exactly this call is
happening.
If the variable you're sending -row to isn't actually typed as an
NSArray, it's likely that you've failed to follow the memory
management rules for that variable. These same symptoms are very
commonly caused by that. Something that responds to -row could have
existed at one point, been deallocated because you didn't -retain it,
and then an NSArray was later allocated in that spot.
Run a "Build & Analyze," and re-re-review the memory management
guidelines until you know them in your sleep.
Source: [NSCFArray row]: unrecognized selector sent to instance 0x3953a20