initialization with a nibFIle failed - iphone

Question

I have a problem.
I try to initialize a variabile in a classViewController created inside a xib file.
I try with the code below but when i append a object to array, these array isn't initialized.
Can you help me?
thanks and sorry for my english.
#import <UIKit/UIKit.h>
#interface AccelerometroViewController : UIViewController <UIAccelerometerDelegate, UITextFieldDelegate, UIAlertViewDelegate>{
//.....
NSMutableArray *arrayPosizioni;
NSMutableArray *arrayPosizioniCorrenti;
NSString *nomePosizioneCorrente;
}
-(IBAction)salvaPosizione;
//...
#property (nonatomic, assign) NSMutableArray *arrayPosizioni;
#property (nonatomic, assign) NSMutableArray *arrayPosizioniCorrenti;
#property (nonatomic, assign) NSString *nomePosizioneCorrente;
#end
#import "AccelerometroViewController.h"
#import "Position.h"
#implementation AccelerometroViewController
float actualX;
float actualY;
float actualZ;
#synthesize arrayPosition;
#synthesize arrayCurrentPosition;
#synthesize nameCurrentPosition;
-(id)init {
self = [super init];
if (self != nil) {
arrayPosition = [[NSMutableArray alloc]init];
arrayCurrentPosition = [[NSMutableArray alloc]init];
nameCurrentPosition = [NSString stringWithFormat:#"noPosition"];
actualX = 0;
actualY = 0;
actualZ = 0;
}
return self;
}
-(void)updateTextView:(NSString*)nomePosizione
{
NSString *string = [NSString stringWithFormat:#"%#", nameCurrentPosition];
textEvent.text = [textEvent.text stringByAppendingString:#"\n"];
textEvent.text = [textEvent.text stringByAppendingString:string];
}
-(IBAction)savePosition{
Posizione *newPosition;
newPosition = [[Position alloc]init];
if([newPosition setValue:(NSString*)fieldNomePosizione.text:(float)actualX:(float)actualY:(float)actualZ]){
//setValue is a method of Position. I'm sure that this method is correct
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Salvataggio Posizione" message:#"Posizione salvata con successo" delegate:self cancelButtonTitle:#"Cancel" otherButtonTitles:nil];
[alert show];
[alert release];
[arrayPosition addObject:newPosition];
}
else{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Salvataggio osizione" message:#"Errore nel salvataggio" delegate:self cancelButtonTitle:#"Cancel" otherButtonTitles:nil];
[alert show];
[alert release];
}
}
- (void) initialise {
arrayPosition = [[NSMutableArray alloc] init];
arrayCurrentPosition = [[NSMutableArray alloc] init];
nameCurrentPosition = #"noPosition";
actualX = 0;
actualY = 0;
actualZ = 0;
}
- (id)initWithNibName:(NSString *)nibName bundle:(NSBundle *)nibBundle {
if (self = [super initWithNibName:nibName bundle:bundle]) {
[self initialise];
}
}

Answer 1

In addition to Felix's comment regarding the mis-naming, your properties are wrong too. Objects need to be retained or copied, not assigned (in most cases) so that you're certain their value won't go away. You need to have ownership of them. As such I would use the following:
#property (nonatomic, readwrite, retain) NSMutableArray *arrayPosition;
#property (nonatomic, readwrite, retain) NSMutableArray *arrayCurrentPosition;
#property (nonatomic, readwrite, copy) NSString *nameCurrentPosition;
Then, since you've retained something you're responsible for releasing it. As such you'll need a dealloc method to do that.
-(void)dealloc {
self.arrayPosition = nil;
self.arrayCurrentPosition = nil;
self.nameCurrentPosition = nil;
[super dealloc];
}