iOS Developer Library — Prerelease

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Core Location Framework Reference CLCircularRegion Class Reference

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CLCircularRegion

The CLCircularRegion class defines the location and boundaries for a circular geographic region. You can use instances of this class to define geo fences for a specific location. The crossing of a geo fence’s boundary causes the location manager to notify its delegate.

  • Initializes and returns a region object defining a circular geographic area.

    Declaration

    Swift

    init(center center: CLLocationCoordinate2D, radius radius: CLLocationDistance, identifier identifier: String)

    Objective-C

    - (instancetype nonnull)initWithCenter:(CLLocationCoordinate2D)center radius:(CLLocationDistance)radius identifier:(NSString * nonnull)identifier

    Parameters

    center

    The center point of the geographic region to monitor.

    radius

    The distance (measured in meters) from the center point of the geographic region to the edge of the circular boundary.

    identifier

    A unique identifier to associate with the region object. You use this identifier to differentiate regions within your application. This value must not be nil.

    Return Value

    An initialized region object.

    Discussion

    When defining a geographic region, remember that the location manager does not generate notifications immediately upon crossing a region boundary. Instead, it applies time and distance criteria to ensure that the crossing was intended and should genuinely trigger a notification. So choose a center point and radius that are appropriate and give you enough time to alert the user. For more information, see the information about region monitoring in Location and Maps Programming Guide.

    Availability

    Available in iOS 7.0 and later.

  • Returns a Boolean value indicating whether the geographic area contains the specified coordinate.

    Declaration

    Swift

    func containsCoordinate(_ coordinate: CLLocationCoordinate2D) -> Bool

    Objective-C

    - (BOOL)containsCoordinate:(CLLocationCoordinate2D)coordinate

    Parameters

    coordinate

    The coordinate to test against the region.

    Return Value

    YEStrue if the coordinate lies within the region’s boundaries or NOfalse if it does not.

    Availability

    Available in iOS 7.0 and later.