Help hiding button in GUI

Question

Hi,
I need some help. I want to hide a button in my app's GUI if a related file is not present in the Documents. Here's the code that tries to hide the button:
tmpStr = [currTxtPath stringByReplacingOccurrencesOfString:@"txt" withString:@"dt"];
NSLog(tmpStr);
BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:tmpStr];
NSLog((fileExists) ? @"YES" : @"NO");
[picInfoButton setHidden:NO];
if (!fileExists) {
[picInfoButton setHidden:YES];
The here's the output on the console, indicating that the file is not present.
2010-05-14 17:47:39.978 myApp[8169:207] */Users/me/Library/Application Support/iPhone Simulator/3.2/Applications/4A86E2E1-8F75-4DC0-9767-63AE1963AD2A/Documents/Text_ 0001.dt*
2010-05-14 17:47:39.979 myApp[8169:207] NO
Given the log info, can someone tell me why the button does not get hidden?
Many thanks,
Sam

Answer 1

Hey Sam -
Your code looks fine, so it's most likely the 'picInfoButton' ivar doesn't point to the button object you're observing. Add another log statement to check that:
tmpStr = [currTxtPath stringByReplacingOccurrencesOfString:@"txt" withString:@"dt"];
NSLog(tmpStr);
BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:tmpStr];
NSLog((fileExists) ? @"YES" : @"NO");
NSLog(@"picInfoButton=%@", picInfoButton); // <-- does this print "(null)"?
[picInfoButton setHidden:NO];
if (!fileExists) {
[picInfoButton setHidden:YES];
If the ivar is nil and the button is defined in a xib, make sure the controller's 'picInfoButton' outlet is connected to the button. If the ivar isn't nil, verify that the address printed in the log is actually the address of the visible button. For example, make sure you didn't reset 'picInfoButton' to a newly created button that was never added to the superview. Also make sure there isn't a second button covering the button that's connected to the ivar.
- Ray