Question

I don’t really have a solid understanding of Setters and Getters for objective-c. Can someone provide a good guide for beginners? I noticed that this comes into play when trying to access variables in another class, which I am trying to do right now. I have two classes, lets say A and B. I have a NSString variable in A with the @property (retain) NSString *variable. Then I go ahead and synthesize it. Now when the view loads in the class I set the value for the variable to “hello”. Now what I want to do is access the string from class B. I have imported the the class A, and initialized it with this code:

AClass *class = [[AClass alloc] init];
NSLog(@"Value:%@", class.variable);
[class release];

However in the debugger it returns a value of “(null)”, which I don’t really understand. If someone could lead me into the right path I would greatly appreciate it.

Thanks,

Kevin

Answer 1

The particular section of interest to you is Declared Properties.

b’s interface should look like:

@interface b : NSObject {
    NSString *value;
}

@property (nonatomic, retain) NSString *value;

- (id) initWithValue:(NSString *)newValue;

@end

Your implementation of b should look something like:

@implementation b

@synthesize value;

- (id) initWithValue:(NSString *)newValue {
    if (self != [super init])
        return nil;

    self.value = newValue;

    return self;
}

@end

Which you could then call like:

b *test = [[b alloc] initWithValue:@"Test!"];
NSLog(@"%@", test.value);