Question

When I construct a dynamic URL using NSString stringWithFormat and then use that value in my XML parser I get random crashes. However if I test it with a constant string it works fine…

This is my code for generating the string,

loginURL = [NSString stringWithFormat:@"%@%@",ScriptURLString,@"authenticate"];

Which results in,

http://edms.digistorm.com.au/test/index.php?s=&sc=D41D8CD98F00B204E9800998ECF8427E&m=authenticate

Then I use it in my XML parser,

XMLReturnData = [[NSMutableArray alloc] init];
xml = [[XMLParser alloc] 
       initWithXMLPath:loginURL 
       lookForElement:@"Authenticate" 
       setCallbackObject:self 
       withSelector:@selector(dataReady) 
       data:XMLReturnData
       ];

For some reason this is causing my app to crash. If I use a constant string like,

loginURL = @"http://edms.digistorm.com.au/test/index.php?s=&sc=D41D8CD98F00B204E9800998ECF8427E&m=authenticate";

it works fine…

loginURL is defined as NSString *loginURL; inside my header file for this view.

Any help or guidance would be much appreciated!

Thanks,
Tim

Answer 1

This shows your string is get released and when you calls it in XML parser it crashes the app.

actually stringWithFormat gives a autorelease object for string.

So what you need,make your string as retain property inside .h then synthesize it in .m and release it in dealloc method.

and also do this,

in viewDidLoad

NSString *tempString=[[NSString alloc] init];  //using this because your string is retain type so it prevent increment in retain count.
self.loginURL=tempString;
[tempString release];

Now when you use stringWithFormat use like this

self.loginURL = [[NSString stringWithFormat:@"%@%@",ScriptURLString,@"authenticate"] retain];

It solves your problem.