I am getting odd behavior from an NSAlert in two different parts of my program. The behavior is:
- Alert appears and then spontaneously disappears.
- Alert reappears and then remains until dismissed by user i.e. normal behavior.
- Alert reappears again.
This behavior only occurs the first time the method that displays the alert is called. After that first time, it behaves normally.
Here is the code for the one of the parts in which the behavior occurs:
UIAlertView * locationAlert = [[UIAlertView alloc] initWithTitle:@"You are in the right place." message:nil delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
[locationAlert show];
[locationAlert release];
Or if you prefer, with a bit more context:
- (IBAction)locateMe {
NSLog(@"About to check location");
locMan = [[CLLocationManager alloc] init];
locMan.delegate = self;
locMan.desiredAccuracy = kCLLocationAccuracyThreeKilometers;
locMan.distanceFilter = 1609; //1 mile
[locMan startUpdatingLocation];
}
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation * )oldLocation {
if (newLocation.horizontalAccuracy >= 0) {
CLLocation *airportLocation = [[[CLLocation alloc] initWithLatitude:51.500148 longitude:-0.204669] autorelease];
CLLocationDistance delta = [airportLocation getDistanceFrom: newLocation];
long miles = (delta * 0.000621371) + 0.5; //metres to rounded mile
if (miles < 3) {
UIAlertView * locationAlert = [[UIAlertView alloc] initWithTitle:@"You are in the right place." message:nil delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
[locationAlert show];
[locationAlert release];
[locMan stopUpdatingLocation];
} else {
UIAlertView * locationAlert = [[UIAlertView alloc] initWithTitle:@"You are not in the right place." message:nil delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
[locationAlert show];
[locationAlert release];
[locMan stopUpdatingLocation];
}
}
}
- (void) locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
UIAlertView * locationAlert = [[UIAlertView alloc] initWithTitle:@"Error." message:error.code delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
[locationAlert show];
[locMan release];
locMan = nil;
}
Any ideas? Thanks.
Edit---------
The other place this happens is:
- (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError {
NSString * errorString = [NSString stringWithFormat:@"Unable to download feed from web site (Error code %i )", [parseError code]];
NSLog(@"error parsing XML: %@", errorString);
UIAlertView * errorAlert = [[UIAlertView alloc] initWithTitle:@"Error loading content" message:errorString delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
[errorAlert show];
}
For context the first case is in the AppDelegate and the second in the view controller for the 1st tab view. The second problem occurs every time the xml is reloaded when there is no internet connection. The first one only occurs the first time the function is called.
Edit-----
If I move the alert it works. Unfortunatly this is not where I want it!
- (IBAction)locateMe {
UIAlertView * locationAlert = [[UIAlertView alloc] initWithTitle:@"You are in the right place." message:nil delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
[locationAlert show];
/*
NSLog(@"About to check location");
locMan = [[CLLocationManager alloc] init];
locMan.delegate = self;
locMan.desiredAccuracy = kCLLocationAccuracyThreeKilometers;
locMan.distanceFilter = 1609; //1 mile
[locMan startUpdatingLocation];*/
}
Update:
I set some NSLog entries and discovered that despite the addition of [locMan stopUpdatingLocation]
the didUpdateToLocation function was running multiple times.
I guess the spontaneous disappearance happens because the alert view is called again and the programme clears the first instance to make way for the second automatically.
Any ideas as to why [locMan stopUpdatingLocation]
doesn't work would be appreciated but in the mean time I just moved the declaration of the locationAlert out of the function (so it is global), set it in the initial locate me function and use the following the first time it is called:
[locationAlert show];
locationAlert = nil;
That way it works perfectly.