UIPickerView: Sorting & displaying an array of values causes crash when moved?

Question

I'm trying to sort an NSMutableArray of Strings into alphabetical order and display the sorted list in an UIPickerView. I'm using another NSArray to create a sorted list.

Im using the PickerView Delegate Methods and have included them in my .h setup: and connected the dataSource & delegate outlets to the filesOwner. In my .h file I have also created an IBOutlet UIPickerView *pickerView; and created a synthesised property for it like this:

@property (nonatomic, retain) IBOutlet UIPickerView *pickerView;

Trying to troubleshoot the problem, I firstly made my unsorted NSMutableArray the source by doing the following:

- (NSString *)pickerView:(UIPickerView *)thePickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {

return [pickerArray objectAtIndex:row];
}

My unsorted MutableArray has no issues and displays the data (unsorted) in the PickerView without problems but when I change the array to my sorted NSArray I get a crash after trying to move the PickerView!? An NSLog of the items in both arrays reveals the same number of items, the same data (displayed differently obviously) however Xcode reports a EXC_BAD_ACCESS?? I can't figure this one out??

Here is my code: (Note: sortedPickerArray is an NSArray and pickerArray is an NSMutableArray declared in my .h file)

- (void)viewDidLoad{

[super viewDidLoad];

sortedPickerArray = [[NSArray alloc] init];

pickerArray = [[NSMutableArray alloc] initWithObjects:
               @"ObjectA",
               @"ObjectB",
               @"ObjectC",
               @"ObjectD",
               nil];

sortedPickerArray = [pickerArray sortedArrayUsingSelector: @selector(caseInsensitiveCompare:)];
[pickerView selectRow:0 inComponent:0 animated:NO];
pickerView.showsSelectionIndicator = YES;}


-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)thePickerView{

return 1;
}

-(NSInteger)pickerView:(UIPickerView *)thePickerView numberOfRowsInComponent:(NSInteger)component{

return [sortedPickerArray count];
}

-(NSString *)pickerView:(UIPickerView *)thePickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
return [sortedPickerArray objectAtIndex:row];
}

-(void)pickerView:(UIPickerView *)thePickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{

NSLog(@"Row %d was selected", row);
}

Any help on this would be greatly appreciated.

Answer 1

I'm assuming in this answer that you're not using ARC since you have a retained property. You assign an autoreleased value to your instance variable with the statement:

sortedPickerArray = [pickerArray sortedArrayUsingSelector: @selector(caseInsensitiveCompare:)];

When you access sortedPickerArray later on it has already been deallocated. So, again assuming you're not using ARC, add a retain in there. And delete the line sortedPickerArray = [[NSArray alloc] init]; as you are leaking this array as of now.