Iphone core location - iphone

Question

I have an application where I have to check that whether user's mobile location has changed or for 30 consecutive seconds or not?If it has not changed in 30 seconds then user will be navigated to the other view and if it has changed then user will have a message that your mobile location's coordinates have changed in these 30 seconds.
I am using these code but it does nothing ...
-(void)time
{
for(int i = 0; i<= timeremaining ;i++)
{
if (new1 == old)
{
if(timeremaining == 1)
{
Timer90 *timerview = [[Timer90 alloc] initWithNibName:#"Timer90" bundle:nil];
[self.navigationController pushViewController:timerview animated:YES];
}
}
else
{
[NSTimer cancelPreviousPerformRequestsWithTarget:self selector:#selector(time) object:nil];
}
timeleft.text = [NSString stringWithFormat:#"%d",timeremaining];
}
timeremaining--;
}
-(void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
new1 = newLocation;
old=oldLocation;
latitude = [[NSString alloc]initWithFormat:#"%g",newLocation.coordinate.latitude];
longitude = [[NSString alloc]initWithFormat:#"%g",newLocation.coordinate.longitude];
accuracy = [[NSString alloc] initWithFormat:#"%g",newLocation.horizontalAccuracy];
if(oldLocation == NULL)
{
oldLocation == newLocation;
}
}
here timer90 is name of my view.Please help me out friends...Any help will be appreciated.

Answer 1

You could possibly do something like this (after adding counter and initialLocation to your properties) it will compare location after 30 seconds following the first update, but I think it would be helpful if you added an age check to the entire method so that you aren't comparing to some very old data point.
-(void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
if(self.counter==0){
self.intialLocation=newLocation;
self.counter=1;
}
NSTimeInterval age = [initialLocation.timestamp timeIntervalSinceNow];
if(age>30)
{
self.counter=0;
if(newLocation.latitude==initialLocation.latitude&&newLocation.longitude==initialLocation.longitude){
Timer90 *timerview = [[Timer90 alloc] initWithNibName:#"Timer90" bundle:nil];
[self.navigationController pushViewController:timerview animated:YES];
}
}
}

Answer 2

Two things that I notice. May be the whole issue, or only part of it.
Number 1.
if(oldLocation == NULL)
{
oldLocation == newLocation;
}
oldLocation == newLocation will not set the two equal to each other (you need one equals sign) and your are assigning the parameter pointers to the same object, not your member pointers. For example, if oldLocation points to Object A and newLocation points to Object B at the start of didUpdateToLocation:fromLocation:, then:
new1 is set to point at Object B
old is set to point at Object A
if(Object A is NULL)
oldLocation and newLocation both point at Object B
The values of new1 and old are not set to the same object in the NULL case. Which is what you are checking for in time
Number 2.
In time you are checking if new1 and old are pointing at the same object. No necessarily if the two objects represent the same location. In the case where oldLocation is null and they are set together, this check may pass...however, it is more likely that CoreLocation will call the update method a few times while accuracy gets better, and you will have two separate objects that represent the same lat/long location.
You should compare these two locations for proximity using the CLLocation getDistanceFromLocation: method.
Hope that Helps!