How do I test the equality of two CLLocations

问题

I'm having a problem with isEqual:

The code:

 if (currentAnchor isEqual:currentBusiness.getCllLocation))
    {
        do a;
    }
    else
    {
        do b;
    }

currentanchor and currentbusiness.getCllocation are locations

But if they are the same, why is function b called? Is something wrong with my code?

回答1:

I assume both of these objects are of type CLLocation, based on the name of getClLocation.

CLLocation doesn't have any specification on what its isEqual: method does, so it's likely just inheriting the implementation of NSObject, which simply compares the pointers of the objects. If you've got two distinct objects with identical data, that isEqual: implementation would return NO. And if you've got two distinct objects with just a slight variation in location, they definitely would not be equal.

You probably don't want isEqual: when comparing location objects. Rather, you probably want to use the distanceFromLocation: method on CLLocation. Something like this would be better:

CLLocationDistance distanceThreshold = 2.0; // in meters
if ([currentAnchor distanceFromLocation:currentBusiness.getCllLocation] < distanceThreshold)
{
  do a;
}
else
{
  do b;
}

回答2:

It's been a while.

What I did is similar with BJ Homer. I just add this.

@interface CLLocation  (equal)
- (BOOL)isEqual:(CLLocation *)other;
@end

@implementation CLLocation  (equal)

- (BOOL)isEqual:(CLLocation *)other {


    if ([self distanceFromLocation:other] ==0)
    {
        return true;
    }
    return false;
}
@end

I was surprised I were the one asking this question :)

回答3:

isEqual just check only objects not their content. you require to create your own method where you access the variables of object and check them for equality using == operator.

回答4:

Swift 4.0 version:

let distanceThreshold = 2.0 // meters
if location.distance(from: CLLocation.init(latitude: annotation.coordinate.latitude,
                                           longitude: annotation.coordinate.longitude)) < distanceThreshold
{ 
    // do a
} else {
    // do b
}

来源：https://stackoverflow.com/questions/6529726/how-do-i-test-the-equality-of-two-cllocations

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objective-c

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iphone-4