Variables emptying or erasing on didSelectRowAtIndexPath - iphone

Question

For some reason, I can't access any of my variables after the first IF Statement in the following code. For instance, if index path is [0,0], then the variable phoneText spits out a phone number. But if its [1,0] or [2,0], I get a "null" return. Why is my variable being erased?
The following function in mapviewcontroller.m sets the values. I do actually have an error here that says "instance method setDetails not found".
- (void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view calloutAccessoryControlTapped:(UIControl *)control {
//this determines what kind of item was selected
if ([control isKindOfClass:[UIButton class]]) {
NSLog(#"Trying to load VenueIdentifier...");
FinderAnnotation *clicked = view.annotation;
FinderViewController *fvi = [self.storyboard instantiateViewControllerWithIdentifier:#"FinderDetail"];
NSString* latitude = [NSString stringWithFormat:#"%f",clicked.coordinate.latitude];
NSString* longitude = [NSString stringWithFormat:#"%f",clicked.coordinate.longitude];
NSLog(#"lat: %#",latitude);
NSLog(#"lon: %#",longitude);
[fvi setDetails:clicked.title phone:clicked.phone address:clicked.address beersavailable:clicked.beersavailable latitude:latitude longitude:longitude];
[self.navigationController pushViewController:fvi animated:YES];
}
}
Then my finderdetail.h creates these variables:
#interface FinderDetail : UITableViewController{
UITableViewCell *phone;
UITableViewCell *address;
UITableViewCell *directions;
UILabel *venueLabel;
NSString *phoneText;
NSString *addressText;
NSString *venueText;
NSString *beersavailable;
NSString *latitudeText;
NSString *longitudeText;
}
#property (nonatomic, retain) IBOutlet UITableViewCell *phone;
#property (nonatomic, retain) IBOutlet UITableViewCell *address;
#property (nonatomic, retain) IBOutlet UITableViewCell *directions;
#property (nonatomic, retain) IBOutlet UILabel *venueLabel;
#property (nonatomic, retain) NSString *phoneText;
#property (nonatomic, retain) NSString *addressText;
#property (nonatomic, retain) NSString *venueText;
#property (nonatomic, retain) NSString *beersavailble;
#property (nonatomic, retain) NSString *latitudeText;
#property (nonatomic, retain) NSString *longitudeText;
#end
Lastly, finderdetail.m grabs these values, assigns them to the variables, and spits them into the table:
#implementation FinderDetail
#synthesize venueLabel, phone, address, directions;
#synthesize phoneText, addressText, venueText, beersavailble, latitudeText, longitudeText;
NSString *notlisted;
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
}
return self;
}
-(void)setDetails:(NSString *)v phone:(NSString *)p address:(NSString *)a beersavailable:(NSString *)ba latitude:(NSString *)lat longitude:(NSString *)lon
{
NSLog(#"venue: %#",v);
NSLog(#"phone: %#",p);
NSLog(#"address: %#",a);
NSLog(#"beersavailable: %#",ba);
NSLog(#"%#",lat);
NSLog(#"%#",lon);
latitudeText = lat;
longitudeText = lon;
phoneText = p;
addressText = a;
venueText = v;
beersavailble = ba;
NSLog(#"%#", latitudeText);
NSLog(#"%#", longitudeText);
notlisted = #"Not Listed";
}
- (void)didReceiveMemoryWarning
{
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
[super viewDidLoad];
NSLog(#"Latitude: %#", latitudeText);
NSLog(#"Longitude: %#", longitudeText);
phone.detailTextLabel.text = phoneText;
address.detailTextLabel.text = addressText;
self.venueLabel.text = venueText;
if(phoneText == nil){
phone.detailTextLabel.text = notlisted;
}
if(addressText == nil){
address.detailTextLabel.text = notlisted;
}
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
//#warning Incomplete method implementation.
// Return the number of rows in the section.
if(section ==0)
return 1;
else
if(section ==1)
return 1;
else
if(section ==2)
return 1;
else
return 0;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"%#",indexPath);
if((indexPath.section==0) && (indexPath.row ==0))
{
NSLog(#"%#",phoneText);
}
if((indexPath.section==1) && (indexPath.row ==0))
{
NSLog(#"%#",addressText);
}
if((indexPath.section==2) && (indexPath.row ==0))
{
NSLog(#"%#",latitudeText);
NSLog(#"%#",longitudeText);
}
}
The initial phoneText will display in an NSLog, but the addressText and latitudeText and longitudeText return null. I can put phoneText in one of those lower if statements and it too returns null. Thanks!!!

Answer 1

You aren't actually using your #property when you are doing the following:
latitudeText = lat;
longitudeText = lon;
phoneText = p;
addressText = a;
venueText = v;
beersavailble = ba;
Also, you are leaking memory every time those assignments are performed after the initial time (when they were still nil).
What you really want is:
self.latitudeText = lat;
self.longitudeText = lon;
self.phoneText = p;
self.addressText = a;
self.venueText = v;
self.beersavailble = ba;
Also, with a NSString (also NSData, NSSet, etc.) #property, it is better to define them as a copy, since it would be perfectly valid to pass in a NSMutableString instead (since it is a subclass of NSString), which then the contents could be altered externally of this object:
#property (nonatomic, copy) NSString *phoneText;
#property (nonatomic, copy) NSString *addressText;
#property (nonatomic, copy) NSString *venueText;
#property (nonatomic, copy) NSString *beersavailble;
#property (nonatomic, copy) NSString *latitudeText;
#property (nonatomic, copy) NSString *longitudeText;
Finally, the fact that you get (NULL) outputted by NSLog suggests the ivars are getting set to nil (and most likely released), and you are using ARC (Automatic Reference Counting), instead of manual retain/release/autorelease.

Answer 2

In setDetails you need to use the properties in order to retain the objects and release previous objects. Assigning directly to the ivars subverts the properties setters/getters and the memory management they provide is lost. Basically if properties are defined use them every time.
Since the objects are not being retained their memory can be reused and unpredictable results can occur such as the values becoming nil.
One way to find such problems is to turn on NSZombies in the simulator runs. I do this occasionally even when I am not having problems just as a check.
To fix the problem rewrite setDetails as:
-(void)setDetails:(NSString *)v phone:(NSString *)p address:(NSString *)a beersavailable:(NSString *)ba latitude:(NSString *)lat longitude:(NSString *)lon
{
self.latitudeText = lat;
self.longitudeText = lon;
self.phoneText = p;
self.addressText = a;
self.venueText = v;
self.beersavailble = ba;
self.notlisted = #"Not Listed";
}
One way to insure that properties are not inadvertently not used is to define the ivars with a slightly different name than the properties. The synthesize statement supports this. Here is how:
in the #interface:
NSString *_latitudeText;
...
#property (nonatomic, retain) NSString *latitudeText;
in the #implementation
#synthesize latitudeText = _latitudeText;