How to solve a error when I call the method [self somemethod] - iphone

Question

I have this code:
// .m
- (void)viewDidLoad {
NSMutableArray *array = [[NSMutableArray alloc] init];
[self addToArray];
}
- (void)addToArray {
NSString *stringA;
[stringA isEqualToString:#"door"];
NSString *stringB;
[stringB isEqualToString:textField.text];
[array addObject:stringA];
if ([stringA isEqual:stringB]) {
[stringA isEqual:nil];
[tableView reloadData];
} else {
[array addObject:stringB];
[tableView reloadData];
}
}
When I call the method addToArray it keeps returning me an error called Thread 1: Program recived signal "EXC_BAD_ACCESS", and the debugger output says : Single stepping until exit from function objc_msgSend, which has no line number information. at the line [self addToArray]. Any idea of how to solve it? I have wasted to much time with it, please help me!

Answer 1

As was said by others, array should be an instance variable or property of the class, declared in the .h file:
#property (strong) NSMutableArray *array;
Or, without ARC:
#property (retain) NSMutableArray *array;
Now you #synthesize array; in your implementation file and can access it from anywhere. Then you can do:
- (void) viewDidLoad
{
self.array = [[NSMutableArray alloc] init];
[self addToArray];
}
You seem to assume that isEqualToString does an assignment. It doesn't, it checks strings for (textual) equality. Try this:
- (void) addToArray
{
NSString *stringA = #"door";
NSString *stringB = textField.text;
[array addObject: stringA];
if (![stringA isEqualToString: stringB])
[array addObject: stringB];
[tableView reloadData];
}

Answer 2

These two variables are uninitialized and will cause you big problems:
NSString *stringA;
[stringA isEqualToString:#"door"];
NSString *stringB;
[stringB isEqualToString:textField.text];
You have not assigned anything to either stringA or stringB. Besides the result of your call to isEqualToString is never used.

Answer 3

Two things I can notice in your code:
1) Make array a class variable, so you can access it from your -[addToArray] method. Better do this in your .h file, for example:
#interface MyViewController : UIViewController {
#private
// ...skipped...
NSMutableArray * array;
// ...rest of class skipped...
}
#end
Then, in your .m file the method should look like this:
// .m
- (void)viewDidLoad {
array = [[NSMutableArray alloc] init];
[self addToArray];
}
And don't forget to release the array:
- (void)dealloc {
[array release];
[super dealloc];
}
2) Do not mess up -[NSString isEqualToString:] method with simple assigment to a variable. So in your -[addToArray] method, for example, replace this:
NSString *stringA;
[stringA isEqualToString:#"door"];
with this:
NSString *stringA = #"door";
And this:
NSString *stringB;
[stringB isEqualToString:textField.text];
with this:
NSString *stringB = textField.text;
3) Check the logic of -[addToArray] method - it is not very clear what are you going achieve.