Going Crazy with UITextField Input in a Very Simple App - objective-c

Question

I have a PromoCodeViewController which is triggered using the following code:
#implementation Demo_WebServiceCallingUsingiOSAppDelegate
#synthesize window = _window,promoCodeController;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
self.promoCodeController = [[PromoCodeViewController alloc] init];
[self.window addSubview:self.promoCodeController.view];
// Override point for customization after application launch.
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}
The PromoCodeViewController contains the UITextField and I implement the UITextFieldDelegate for the PromoCodeViewController as shown:
#interface PromoCodeViewController : UIViewController<UITextFieldDelegate>
{
IBOutlet UITextField *promoCodeTextField;
}
#property (nonatomic,retain) IBOutlet UITextField *promoCodeTextField;
#end
I implement the textFieldShouldReturn method as shown:
- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
return TRUE;
}
I have even setup the PromoCodeViewController to be the delegate for the UITextField events. When I start typing in the TextBox it throws "Program received signal. EXC_BAD_ACCESS". It happens when I type second character in the UITextField. What am I doing wrong?
UPDATE 1:
The error comes on the following section:
int main(int argc, char *argv[])
{
#autoreleasepool {
return UIApplicationMain(argc, argv, nil, NSStringFromClass([Demo_WebServiceCallingUsingiOSAppDelegate class]));
}
}

Answer 1

It looks as though you're missing an #synthesize statement for the promoCodeTextField property. Add the following to your Demo_WebServiceCallingUsingiOSAppDelegate class (which by the way, might benefit from renaming):
#synthesize promoCodeTextField = _promoCodeTextField;
Without the #synthesize statement, Xcode's Nib File Editor will directly set the instance variable instead of calling the accessor methods (since they don't exist); as a consequence the text field is never retained.

Answer 2

What object is the delegate of the textfield? Objects do not usually retain their delegates (since the delegate is often retaining a reference to the object, and retain-cycles lead to memory leaks).
My hunch is that your text field's delegate is defined and attached in your nib, but isn't being retained anywhere, so shortly after the nib is loaded the delegate is deallocated. As soon as the text field attempts to do anything with the delegate, it crashes.
If so, make sure something (usually the application delegate) is retaining a reference to whatever object is serving as the delegate of your text field.