CLLocationManager Class
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Manages the delivery of location, region, and heading events to your application.
[Foundation.Register("CLLocationManager", true)]
public class CLLocationManager : Foundation.NSObjecttype CLLocationManager = class
inherit NSObject- Inheritance
- Attributes
Remarks
Requesting Authorization
Starting with iOS 8, developers that want to request access to the location information must request permission from the user to do so before they can receive events. This is done by calling either the RequestWhenInUseAuthorization() or the RequestAlwaysAuthorization() methods. When these methods are invoked, the system will prompt the user for authorization, and if he grants it, the AuthorizationChanged event will be raised if set (or if you are using the Delegate idiom, the AuthorizationChanged(CLLocationManager, CLAuthorizationStatus) method will be invoked.
Additionally, developers must add one or both of the keys NSLocationWhenInUseUsageDescription and NSLocationAlwaysUsageDescription in their app's info.plist. These keys are strings that can be used to describe why the app needs location access.
Developers should use an idiom like this:
var manager = new CLLocationManager();
manager.AuthorizationChanged += (sender, args) => {
Console.WriteLine ("Authorization changed to: {0}", args.Status);
};
if (UIDevice.CurrentDevice.CheckSystemVersion(8,0))
manager.RequestWhenInUseAuthorization();
Tracking the device's location
The most common use-case for the CLLocationManager is tracking the device while the application is in the foreground. (See also "Background Updating and Deferred Mode" below.)
Application developers may use either C#-style events or Apple's delegate-object pattern to track foreground location updating. For C#-style events, developers can use the LocationsUpdated event:
var mgr = new CLLocationManager();
mgr.LocationsUpdated += (sender, e) => {
foreach(var loc in e.Locations)
{
Console.WriteLine(loc);
}
};
mgr.StartUpdatingLocation();
let mgr = new CLLocationManager()
mgr.LocationsUpdated.Add( fun e ->
e.Locations |> Seq.map Console.WriteLine |> ignore )
mgr.StartUpdatingLocations()
While C#-style events are more concise, the CLLocationManager must use the delegate-object pattern for certain behaviors (for instance, deferred updating), and it may be more consistent for an application to use the delegate-object pattern even when C#-style events are available. The delegate-object pattern consists of assigning a customized CLLocationManagerDelegate object to the Delegate property of the CLLocationManager:
var mgr = new CLLocationManager();
mgr.Delegate = new MyLocationDelegate();
mgr.StartUpdatingLocation();
//...etc...
public class MyLocationDelegate : CLLocationManagerDelegate {
public override void LocationsUpdated (CLLocationManager manager, CLLocation[] locations) {
foreach(var loc in locations) {
Console.WriteLine(loc);
}
}
}
let mgr = new CLLocationManager()
mgr.Delegate <- new MyLocationDelegate()
mgr.StartUpdatingLocation()
//...etc...
type MyLocationDelegate () = inherit CLLocationManagerDelegate()
override this.LocationsUpdated ( manager : CLLocationManager, locations : CLLocation[] ) =
locations
|> Seq.map Console.WriteLine
|> ignore
Region monitoring (Geofencing)
The CLLocationManager can track the device's entry and exit from geographical regions (geofences). A region will be a subtype of CLRegion : either a CLCircularRegion or a region associated with an iBeacon, of type CLBeaconRegion.
CLRegion identity should only be compared via the Identifier property. Regions are monitored at the operating-system level and new CLRegion objects with the specified Identifier may be instantiated by the system when the device enters or exists an area; these CLRegions will be different objects (myExpectedRegion != myReceivedRegion) but will have the same Identifier (myExpectedRegion.Identifier.Equals(myReceivedRegion.Identifier, StringComparison.Ordinal)).
Application developers can use either C#-style events or Apple's delegate-object pattern:
var rgn = new CLCircularRegion(new CLLocationCoordinate2D(latitude, longitude), 50, "target");
mgr = new CLLocationManager();
mgr.RegionEntered += (s,e) => Console.WriteLine("Entered region " + e.Region.Identifier);
mgr.RegionLeft += (s,e) => Console.WriteLine("Left region " + e.Region.Identifier);
mgr.StartMonitoring(rgn);
let rgn = new CLCircularRegion(new CLLocationCoordinate2D(latitude, longitude), 50, "target")
let mgr = new CLLocationManager()
mgr.RegionEntered.Add( fun e -> Console.WriteLine("Entered region " + e.Region.Identifier))
mgr.RegionLeft.Add( fun e -> Console.WriteLine("Left region " + e.Region.Identifier))
mgr.StartMonitoring(rgn)
var rgn = new CLCircularRegion(new CLLocationCoordinate2D(latitude, longitude), 50, "target");
mgr = new CLLocationManager();
var del = new MyLocationDelegate();
mgr.Delegate = del;
mgr.StartMonitoring(rgn);
//...etc...
public class MyLocationDelegate : CLLocationManagerDelegate {
public override void RegionEntered (CLLocationManager mgr, CLRegion rgn) {
Console.WriteLine ("Entered region " + rgn.Identifier);
}
public override void RegionLeft (CLLocationManager mgr, CLRegion rgn) {
Console.WriteLine ("Left region " + rgn.Identifier);
}
}
let rgn = new CLCircularRegion(new CLLocationCoordinate2D(latitude, longitude), 50, "target")
let mgr = new CLLocationManager()
mgr.Delegate <- new MyLocationDelegate()
mgr.StartMonitoring(rgn)
//...etc...
type MyLocationDelegate () = inherit CLLocationManagerDelegate()
override this.RegionEntered ( mgr : CLLocationManager, rgn : CLRegion ) =
Console.WriteLine ("Entered region " + rgn.Identifier)
override this.RegionLeft ( mgr : CLLocationManager, rgn : CLRegion ) =
Console.WriteLine ("Left region " + rgn.Identifier)
iBeacon Ranging
In iOS 7, Apple introduced iBeacons, which combine region-processing using server and GPS services and nearby promixity ranging using Bluetooth Low-Energy (BLE) signaling.
Once within a CLBeaconRegion (see previous section), applications may track "ranging" events relating to fine-grained changes in the distance between the device and nearby iBeacons. iBeacon ranging is primarily a function of radio signal strength, which can vary significantly based on environment, electrical noise, etc. Application developers should not attempt to estimate precise distances from the Proximity or P:CoreLocation.CLBeacon.RSSI properties.
Ranging is done with code similar to:
iBeacons also support "ranging" for determining physical proximity with a higher precision with the Proximity property. The following example shows how ranging should be used as a qualitative measure:
locationManager.DidRangeBeacons += (lm, rangeEvents) => {
switch(rangeEvents.Beacons[0].Proximity){
case CLProximity.Far :
Console.WriteLine("You're getting colder!");
break;
case CLProximity.Near :
Console.WriteLine("You're getting warmer!");
break;
case CLProximity.Immediate :
Console.WriteLine("You're red hot!");
break;
locationManager.DidRangeBeacons.Add(fun rangeEvents ->
let s = match rangeEvents.Beacons.[0].Proximity with
| CLProximity.Far -> "You're getting colder!"
| CLProximity.Near -> "You're getting warmer!"
| CLProximity.Immediate -> "You're red hot!"
| CLProximity.Unknown -> "I can't tell"
| _ -> raise(ArgumentOutOfRangeException("Unknown argument"))
Console.WriteLine(s)
)
locationManager.StartRangingBeacons(beaconRegion)
<key>UIBackgroundModes</key>
<array>
<string>location</string>
</array>
Power consumption is an important consideration for all backgrounding scenarios. In the case of location data, GPS-enabled hardware may be able to record and cache accurate location but defer the delivery to the application for some amount of time. This "deferred mode" has several constraints:
- GPS hardware must be available:
- The Delegate property must be assigned to an object whose class implements the LocationsUpdated(CLLocationManager, CLLocation[]) method.:
- The DesiredAccuracy property must be set to AccuracyBest or AccurracyBestForNavigation.:
If those conditions are satisfied, the application can request deferred delivery when backgrounded by calling the AllowDeferredLocationUpdatesUntil(Double, Double) method.
Importance of Delegate object
Generally, when using Xamarin.iOS, developers can freely choose whether to use C# events or Apple-style "delegate objects" to react to object lifecycle events. Several CLLocationManager methods, however, require the delegate-object pattern. For instance, AllowDeferredLocationUpdatesUntil(Double, Double) will raise a runtime exception if the Delegate property is not set to an object whose class implements LocationsUpdated(CLLocationManager, CLLocation[]) method.
Constructors
| CLLocationManager() |
Default constructor that initializes a new instance of this class with no parameters. |
| CLLocationManager(IntPtr) |
A constructor used when creating managed representations of unmanaged objects; Called by the runtime. |
| CLLocationManager(NSObjectFlag) |
Constructor to call on derived classes to skip initialization and merely allocate the object. |
Properties
| ActivityType |
Used to provide the operating system clues for better power consumption / accuracy. |
| AllowsBackgroundLocationUpdates |
Gets or sets a Boolean value that controls whether the application will respond to location updates while it is suspended. |
| Class | (Inherited from NSObject) |
| ClassHandle |
The handle for this class. |
| DebugDescription |
A developer-meaningful description of this object. (Inherited from NSObject) |
| DeferredLocationUpdatesAvailable |
Whether background-generated deferred location data are available. |
| Delegate |
An instance of the CoreLocation.ICLLocationManagerDelegate model class which acts as the class delegate. |
| Description |
Description of the object, the Objective-C version of ToString. (Inherited from NSObject) |
| DesiredAccuracy |
The accuracy preferred by the app. (Coarser accuracies consume less power.) |
| DistanceFilter |
The minimum horizontal distance, in meters, the device has to move before issuing a location update. |
| Handle |
Handle (pointer) to the unmanaged object representation. (Inherited from NSObject) |
| Heading |
The most recent heading (direction in which the device is traveling). |
| HeadingAvailable |
Whether the Heading property is not |
| HeadingFilter |
The minimum change in heading, in degreees, necessary to generate a location update. |
| HeadingOrientation |
The orientation used to determine heading calculations. |
| IsDirectBinding | (Inherited from NSObject) |
| IsProxy | (Inherited from NSObject) |
| IsRangingAvailable |
Gets a Boolean value that tells whether the device can range Bluetooth beacons. |
| Location |
The most recently-retrieved CLLocation. |
| LocationServicesEnabled |
Whether location services are available. |
| MaximumRegionMonitoringDistance |
The largest boundary distance, in meters, that can be assigned to a region. |
| MaxTimeInterval |
Represents the value associated with the constant CLTimeInternalMax |
| MonitoredRegions |
The set of CLRegions being monitored by the app. |
| PausesLocationUpdatesAutomatically |
Whether the system is allowed to pause location updates (for instance, if the device has not moved in awhile). |
| Purpose |
Developers should not use this deprecated property. |
| RangedRegions |
The set of CLRegions being tracked using ranging. |
| RegionMonitoringAvailable |
Application developers should use IsMonitoringAvailable(Type) rather than this deprecated method. |
| RegionMonitoringEnabled |
Application developers should use IsMonitoringAvailable(Type) rather than this deprecated method. |
| RetainCount |
Returns the current Objective-C retain count for the object. (Inherited from NSObject) |
| Self | (Inherited from NSObject) |
| ShouldDisplayHeadingCalibration |
Delegate invoked by the object to get a value. |
| ShowsBackgroundLocationIndicator | |
| SignificantLocationChangeMonitoringAvailable |
Whether "significant location change" monitoring (e.g., via cell tower switch) is available. |
| Status |
The authorization status of the app (e.g., if the app is denied access to location services). |
| Superclass | (Inherited from NSObject) |
| SuperHandle |
Handle used to represent the methods in the base class for this NSObject. (Inherited from NSObject) |
| WeakDelegate |
An object that can respond to the delegate protocol for this type |
| Zone | (Inherited from NSObject) |
Methods
| AddObserver(NSObject, NSString, NSKeyValueObservingOptions, IntPtr) |
Registers an object for being observed externally (using NSString keyPath). Observed changes are dispatched to the observer’s object ObserveValue(NSString, NSObject, NSDictionary, IntPtr) method. (Inherited from NSObject) |
| AddObserver(NSObject, String, NSKeyValueObservingOptions, IntPtr) |
Registers an object for being observed externally (using string keyPath). Observed changes are dispatched to the observer’s object ObserveValue(NSString, NSObject, NSDictionary, IntPtr) method. (Inherited from NSObject) |
| AddObserver(NSString, NSKeyValueObservingOptions, Action<NSObservedChange>) |
Registers an object for being observed externally using an arbitrary method. (Inherited from NSObject) |
| AddObserver(String, NSKeyValueObservingOptions, Action<NSObservedChange>) |
Registers an object for being observed externally using an arbitrary method. (Inherited from NSObject) |
| AllowDeferredLocationUpdatesUntil(Double, Double) |
Suggests that location updates are deferred until either |
| AwakeFromNib() |
Called after the object has been loaded from the nib file. Overriders must call base.AwakeFromNib(). (Inherited from NSObject) |
| BeginInvokeOnMainThread(Action) | (Inherited from NSObject) |
| BeginInvokeOnMainThread(Selector, NSObject) |
Invokes asynchrously the specified code on the main UI thread. (Inherited from NSObject) |
| Bind(NSString, NSObject, String, NSDictionary) | (Inherited from NSObject) |
| Bind(String, NSObject, String, NSDictionary) |
Obsolete.
(Inherited from NSObject)
|
| BindingInfo(String) |
Obsolete.
(Inherited from NSObject)
|
| BindingOptionDescriptions(String) |
Obsolete.
(Inherited from NSObject)
|
| BindingValueClass(String) |
Obsolete.
(Inherited from NSObject)
|
| CommitEditing() | (Inherited from NSObject) |
| CommitEditing(NSObject, Selector, IntPtr) | (Inherited from NSObject) |
| ConformsToProtocol(IntPtr) |
Invoked to determine if this object implements the specified protocol. (Inherited from NSObject) |
| Copy() |
Performs a copy of the underlying Objective-C object. (Inherited from NSObject) |
| DangerousAutorelease() | (Inherited from NSObject) |
| DangerousRelease() | (Inherited from NSObject) |
| DangerousRetain() | (Inherited from NSObject) |
| DidChange(NSKeyValueChange, NSIndexSet, NSString) |
Indicates a change occurred to the indexes for a to-many relationship. (Inherited from NSObject) |
| DidChange(NSString, NSKeyValueSetMutationKind, NSSet) | (Inherited from NSObject) |
| DidChangeValue(String) |
Indicates that a change occurred on the specified key. (Inherited from NSObject) |
| DisallowDeferredLocationUpdates() |
Turns off deferred background location updates. |
| DismissHeadingCalibrationDisplay() |
Removes the heading calibration view from the display. |
| Dispose() |
Releases the resources used by the NSObject object. (Inherited from NSObject) |
| Dispose(Boolean) |
Releases the resources used by the CLLocationManager object. |
| DoesNotRecognizeSelector(Selector) |
Indicates that this object does not recognize the specified selector. (Inherited from NSObject) |
| Equals(NSObject) | (Inherited from NSObject) |
| Equals(Object) | (Inherited from NSObject) |
| ExposedBindings() | (Inherited from NSObject) |
| GetBindingInfo(NSString) | (Inherited from NSObject) |
| GetBindingOptionDescriptions(NSString) | (Inherited from NSObject) |
| GetBindingValueClass(NSString) | (Inherited from NSObject) |
| GetDictionaryOfValuesFromKeys(NSString[]) |
Retrieves the values of the specified keys. (Inherited from NSObject) |
| GetHashCode() |
Generates a hash code for the current instance. (Inherited from NSObject) |
| GetMethodForSelector(Selector) | (Inherited from NSObject) |
| GetNativeField(String) |
Obsolete.
(Inherited from NSObject)
|
| GetNativeHash() | (Inherited from NSObject) |
| Init() | (Inherited from NSObject) |
| InitializeHandle(IntPtr, String) | (Inherited from NSObject) |
| InitializeHandle(IntPtr) | (Inherited from NSObject) |
| Invoke(Action, Double) | (Inherited from NSObject) |
| Invoke(Action, TimeSpan) | (Inherited from NSObject) |
| InvokeOnMainThread(Action) | (Inherited from NSObject) |
| InvokeOnMainThread(Selector, NSObject) |
Invokes synchrously the specified code on the main UI thread. (Inherited from NSObject) |
| IsEqual(NSObject) | (Inherited from NSObject) |
| IsKindOfClass(Class) | (Inherited from NSObject) |
| IsMemberOfClass(Class) | (Inherited from NSObject) |
| IsMonitoringAvailable(Class) |
Determines whether the device supports region monitoring for the specified kind of CLRegion. |
| IsMonitoringAvailable(Type) |
Determines whether the device supports region monitoring for the specified kind of CLRegion. |
| MarkDirty() |
Promotes a regular peer object (IsDirectBinding is true) into a toggleref object. (Inherited from NSObject) |
| MutableCopy() |
Creates a mutable copy of the specified NSObject. (Inherited from NSObject) |
| ObjectDidEndEditing(NSObject) | (Inherited from NSObject) |
| ObserveValue(NSString, NSObject, NSDictionary, IntPtr) |
Indicates that the value at the specified keyPath relative to this object has changed. (Inherited from NSObject) |
| PerformSelector(Selector, NSObject, Double, NSString[]) | (Inherited from NSObject) |
| PerformSelector(Selector, NSObject, Double) |
Invokes the selector on the current instance and if the |
| PerformSelector(Selector, NSObject, NSObject) | (Inherited from NSObject) |
| PerformSelector(Selector, NSObject) | (Inherited from NSObject) |
| PerformSelector(Selector, NSThread, NSObject, Boolean, NSString[]) | (Inherited from NSObject) |
| PerformSelector(Selector, NSThread, NSObject, Boolean) | (Inherited from NSObject) |
| PerformSelector(Selector) | (Inherited from NSObject) |
| PrepareForInterfaceBuilder() | (Inherited from NSObject) |
| RemoveObserver(NSObject, NSString, IntPtr) |
Stops the specified observer from receiving further notifications of changed values for the specified keyPath and context. (Inherited from NSObject) |
| RemoveObserver(NSObject, NSString) |
Stops the specified observer from receiving further notifications of changed values for the specified keyPath. (Inherited from NSObject) |
| RemoveObserver(NSObject, String, IntPtr) |
Stops the specified observer from receiving further notifications of changed values for the specified keyPath and context. (Inherited from NSObject) |
| RemoveObserver(NSObject, String) |
Stops the specified observer from receiving further notifications of changed values for the specified keyPath. (Inherited from NSObject) |
| RequestAlwaysAuthorization() |
Displays an interface to the user that requests authorization to use location services any time that the app is running. |
| RequestLocation() |
Requests the current location. |
| RequestState(CLRegion) |
Asynchronously requests information on the state of the |
| RequestWhenInUseAuthorization() |
Displays an interface to the user that requests authorization to use location services any time that the app is in the foreground. |
| RespondsToSelector(Selector) |
Whether this object recognizes the specified selector. (Inherited from NSObject) |
| SetNativeField(String, NSObject) |
Obsolete.
(Inherited from NSObject)
|
| SetNilValueForKey(NSString) |
Sets the value of the specified key to null. (Inherited from NSObject) |
| SetValueForKey(NSObject, NSString) |
Sets the value of the property specified by the key to the specified value. (Inherited from NSObject) |
| SetValueForKeyPath(IntPtr, NSString) |
A constructor used when creating managed representations of unmanaged objects; Called by the runtime. (Inherited from NSObject) |
| SetValueForKeyPath(NSObject, NSString) |
Sets the value of a property that can be reached using a keypath. (Inherited from NSObject) |
| SetValueForUndefinedKey(NSObject, NSString) |
Indicates an attempt to write a value to an undefined key. If not overridden, raises an NSUndefinedKeyException. (Inherited from NSObject) |
| SetValuesForKeysWithDictionary(NSDictionary) |
Sets the values of this NSObject to those in the specified dictionary. (Inherited from NSObject) |
| StartMonitoring(CLRegion, Double) |
Starts monitoring the region. |
| StartMonitoring(CLRegion) |
Begins monitoring |
| StartMonitoringSignificantLocationChanges() |
Starts monitoring for significant changes. |
| StartMonitoringVisits() |
Starts generating events in response to visits. |
| StartRangingBeacons(CLBeaconRegion) |
Starts delivering notifications about beacons in |
| StartUpdatingHeading() |
Starts updating the heading. |
| StartUpdatingLocation() |
Starts updating the location |
| StopMonitoring(CLRegion) |
Stops monitoring the |
| StopMonitoringSignificantLocationChanges() |
Starts monitoring significant location changes. |
| StopMonitoringVisits() |
Stops generating events in response to visits. |
| StopRangingBeacons(CLBeaconRegion) |
Stops tracking beacons in the |
| StopUpdatingHeading() |
Stops updating the heading. |
| StopUpdatingLocation() |
Stops updating the location. |
| ToString() |
Returns a string representation of the value of the current instance. (Inherited from NSObject) |
| Unbind(NSString) | (Inherited from NSObject) |
| Unbind(String) |
Obsolete.
(Inherited from NSObject)
|
| ValueForKey(NSString) |
Returns the value of the property associated with the specified key. (Inherited from NSObject) |
| ValueForKeyPath(NSString) |
Returns the value of a property that can be reached using a keypath. (Inherited from NSObject) |
| ValueForUndefinedKey(NSString) |
Indicates an attempt to read a value of an undefined key. If not overridden, raises an NSUndefinedKeyException. (Inherited from NSObject) |
| WillChange(NSKeyValueChange, NSIndexSet, NSString) |
Indicates that the values of the specified indices in the specified key are about to change. (Inherited from NSObject) |
| WillChange(NSString, NSKeyValueSetMutationKind, NSSet) | (Inherited from NSObject) |
| WillChangeValue(String) |
Indicates that the value of the specified key is about to change. (Inherited from NSObject) |
Events
| AuthorizationChanged |
Event raised by the object. |
| DeferredUpdatesFinished |
Event raised by the object. |
| DidDetermineState |
Event raised by the object. |
| DidRangeBeacons |
Event raised by the object. |
| DidStartMonitoringForRegion |
Event raised by the object. |
| DidVisit |
Event raised by the object. |
| Failed |
Event raised by the object. |
| LocationsUpdated |
Event raised by the object. |
| LocationUpdatesPaused |
Event raised by the object. |
| LocationUpdatesResumed |
Event raised by the object. |
| MonitoringFailed |
Event raised by the object. |
| RangingBeaconsDidFailForRegion |
Event raised by the object. |
| RegionEntered |
Event raised by the object. |
| RegionLeft |
Event raised by the object. |
| UpdatedHeading |
Event raised by the object. |
| UpdatedLocation |
Event raised by the object. |