Question

I had to detect if user has touched on the iPhone screen. So, I created a class named “CustomApplication” in my project (subclassing UIApplication) and then, I modified my main.m to look like this:

NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
int retVal = UIApplicationMain(argc, argv, @"CustomApplication",nil);
[pool release];
return retVal;

This class “CustomApplication.m” contains a method as follows:

- (void)sendEvent:(UIEvent *)event {
[super sendEvent:event];
[MyUtility showAlertWithTitle:@"Alert!!!!" message:@"Session Expired!!!!"]; // showing an alert here
}

The Method showAlertWithTitle looks like this:

+ (void) showAlertWithTitle:(NSString *)aTitle message:(NSString *)aMessage
{
UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:aTitle message:aMessage delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alertView show]; // Line causing problem in iOS 5 - base sdk 5.0
[alertView release];

}

Everythings working fine in iOS 4.2, but on iOS 5.0 the app is crashing on touching the screen (when sendEvent:event method gets called). When I debugged the code, I found that the problem is in [alertView show]; line. In iOS 5, what is happening is when this particular line ([alertView show];) gets executed, it again calls sendEvent method of CustomApplication and this method calls showAlertWithTitle: method of MyUtility which in turn again calls sendEvent method and hence, the code is entering into infinite loop. I dont know the solution. If someone has faced this weired thing, then please tell me what should I write so that when alert is being showed the sendEvent method doesn’t get called?

Answer 1

This may not seem like the best approach, but It may work. Have you tried simply including a static boolean variable in your code, so that the function does not get called again?

Somewhere up

BOOL stopHere = NO;

And then the sendEvent

-(void)sendEvent:(UIEvent *)event{
    [super sendEvent:event];
    if (!skipHere){
        skipHere = YES;
        [MyUtility showAlertWithTitle:@"Alert!!!!" message:@"Session Expired!!!!"]; // show        
    skipHere=NO;
    }
    }