NSURL not working after retrieved from NSMutableArray - ios

Question

Having trouble storing an audio recording file address in an array and using it later.
This is how I get the URL address, convert it to a string and add it to the array. This seems to work.
testViewController.h
#interface record_audio_testViewController : UIViewController <AVAudioRecorderDelegate> {
NSURL *audioFile;
AVAudioRecorder *recorder;
...
}
#property (nonatomic, retain) NSURL *audioFile;
testViewController.m
#import "record_audio_testViewController.h"
#implementation record_audio_testViewController
#synthesize audioFile
- (void)viewDidLoad {
NSMutableArray *urlArray = [[NSMutableArray alloc] init];
audioFile = [NSURL fileURLWithPath:[NSTemporaryDirectory() stringByAppendingPathComponent: [NSString stringWithFormat: #"%.0f.%#", [NSDate timeIntervalSinceReferenceDate] * 1000.0, #"caf"]]];
// convert NSURL to NSString
NSString *fileLoc = [audioFile absoluteString];
[urlArray addObject: fileLoc ];
[[NSUserDefaults standardUserDefaults] setObject:urlArray forKey:#"urlArray"];
[[NSUserDefaults standardUserDefaults] synchronize];
[urlArray release];
// Create an AVAudioSession object.
AVAudioSession *audioSession = [AVAudioSession sharedInstance];
[audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error: &error];
//Activate the session
[audioSession setActive:YES error: &error];
}
- (void)buttonClicked:(UIButton*)button {
NSMutableArray *urlArray;
urlArray = [[NSUserDefaults standardUserDefaults] objectForKey:#"urlArray"];
audioFile = [NSURL URLWithString: [urlArray objectAtIndex:btnN] ];
// at this point, the URL looks exactly as created
}
- (IBAction) rec_button_pressed {
NSMutableDictionary* recordSetting = [[NSMutableDictionary alloc] init];
[recordSetting setValue :[NSNumber numberWithInt:kAudioFormatAppleIMA4] forKey:AVFormatIDKey];
[recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey];
[recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey];
recorder = [[ AVAudioRecorder alloc] initWithURL: audioFile settings: recordSetting error:&error ]; // this is where it CRASHES
[recorder setDelegate:self];
[recorder prepareToRecord];
[recorder record];
}
When I use NSLog to look at and compare these addresses, they all look the same. But the program throws an exception:
Thread 1: EXC_BAD_ACCESS (code=2 address=0x9)
Anyone know how to get through this situation?
Also, are there easier and/or safer ways to do this?

Answer 1

The code you're showing could be completely irrelevant, since it isn't here that the exception is being thrown. The exception is probably due to a memory management error, and might have nothing to do with NSURL. You are just guessing about that - and you shouldn't be.
There is no memory management in your code, and since you are not using ARC, that suggests that you're unaware of your memory management responsibilities. My book explains them to you, and also explains why you should use ARC if you can:
http://www.apeth.com/iOSBook/ch12.html
Also, use the static analyzer; it will spot some of the danger signs of memory mismanagement.