Cosc 5/4730 GPS/Location android.location

Simulator notes All the simulators can simulator GPS/location information – Android DDMS commands (geo) to the emulator.

Android basics Get a LocationManger from the system Choose a provider with Criteria or just a provider – providers: gps, network, etc… get the Location and use the data. Use a LocationListener

Permissions Add them to the AndroidManifest.xml – Maybe needed for some things, but needed the mapactivity. – GPS location – Cell_ID or WiFI location There maybe other needed as well – ACCESS_LOCATION_EXTRA_COMMANDS, ACCESS_MOCK_LOCATION – See CN/reference/android/Manifest.permission.html for all permissions.

android.location package Address – A class representing an Address, i.e, a set of Strings describing a location. Criteria – A class indicating the application criteria for selecting a location provider. Geocoder – A class for handling geocoding and reverse geocoding. GpsSatellite – This class represents the current state of a GPS satellite. GpsStatus – This class represents the current state of the GPS engine. Location – A class representing a geographic location sensed at a particular time (a "fix"). LocationManager – This class provides access to the system location services. LocationProvider – An abstract superclass for location providers.

android.location package (2) Listeners GpsStatus.Listener – Used for receiving notifications when GPS status has changed. GpsStatus.NmeaListener – Used for receiving NMEA sentences from the GPS. LocationListener – Used for receiving notifications from the LocationManager when the location has changed. A addProximityAlert(double latitude, double longitude, float radius, long expiration, PendingIntent intent) can be added to the LocationManger – Sets a proximity alert for the location given by the position (latitude, longitude) and the given radius.

LocationManager This is the factory class to get location information – You do not instantiate this class directly, retrieve it through Context.getSystemService(Context.LOCATION_SERVIC E) – Now you can get a Location information with getLastKnownLocation(String Provider); – and more information about the provider with LocationProvider getProvider(String name) Providers are found in a couple of ways

Providers List getProviders(Boolean enabledOnly) – get a list of providers, true for ones that are working String getBestProvider(Criteria criteria, boolean enabledOnly) – get a provider based on Criteria List getAllProviders() – Returns a list of all providers – You can use boolean isProvidersEnabled(String) to determine if it is enabled or not.

LocationProvider Information about the Provider int getAccuracy(), int getPowerRequirement(), boolean hasMonetaryCost() boolean meetsCriteria(Criteria criteria) boolean requiresCell() – Returns true if the provider requires access to an appropriate cellular network (e.g., to make use of cell tower IDs), false otherwise. boolean requiresNetwork() – Returns true if the provider requires access to a data network (e.g., the Internet), false otherwise. boolean requiresSatellite() – Returns true if the provider requires access to a satellite-based positioning system (e.g., GPS), false otherwise. boolean supportsAltitude() – Returns true if the provider is able to provide altitude information, false otherwise. boolean supportsBearing() – Returns true if the provider is able to provide bearing information, false otherwise. boolean supportsSpeed() – Returns true if the provider is able to provide speed information, false otherwise.

Criteria UnitsDefault ValueSetterAccessor Horizontal accuracy Meters NO_REQUIREMENT setHorizontalAccura cy getHorizontalAccur acy Vertical accuracyMeters NO_REQUIREMENT setVerticalAccuraygetVerticalAccuracy Preferred response time Milliseconds NO_REQUIREMENT setPreferredRespon seTime getPreferredRespon seTime Power consumption int NO_REQUIREMENT setPreferredPowerC onsumption getPreferredPower Consumption Cost allowedboolean true (allowed to cost) setCostAllowedisAllowedToCost Speed and course required boolean false (not required) setSpeedAndCourse Required getSpeedAndCours eRequired Altitude requiredboolean false (not required) setAltitudeRequiredgetAltitudeRequire d Address requiredboolean false (not required) setAddressInfoRequ ired getAddressInfoRequ ired Note: NO_REQUIREMENT, POWER_USAGE_LOW, POWER_USAGE_MEDIUM, POWER_USAGE_HIGH are field constants

Location Has a standard set of getters you would expect – double getLatitude(), double getLongitude(), float getSpeed(), double getAltitude() – long getTime() Returns the UTC time of this fix, in milliseconds since January 1, – float getAccuracy() Returns the accuracy of the fix in meters. – float getBearing() Returns the direction of travel in degrees East of true North. – Returns true if has X hasAltitude(), hasBearing(), hasSpeed(), hasAccuracy()

Location (2) float bearingTo(Location dest) – Returns the approximate initial bearing in degrees East of true North when traveling along the shortest path between this location and the given location. static void distanceBetween(double startLatitude, double startLongitude, double endLatitude, double endLongitude, float[] results) – Computes the approximate distance in meters between two locations, and optionally the initial and final bearings of the shortest path between them. float distanceTo(Location dest) – Returns the approximate distance in meters between this location and the given location.

Example code get a location LocationManager myL = (LocationManager) getBaseContext().getSystemService(Context.LOCATION_SERVICE); //or use (LocationManager) getContext().getSystemService(Context.LOCATION_SERVICE); Location loc = myL.getLastKnownLocation("gps"); if (loc != null ) { double sLatitude = loc.getLatitude(); double sLongitude = loc.getLongitude(); String location = sLatitude+","+sLongitude; } else { //No location can be found with gps }

LocationListener Create a LocationListener or implement LocationListener in a class The following methods must be implemented – void onLocationChanged(Location location) Called when the location has changed. – void onProviderDisabled(String provider) Called when the provider is disabled by the user. – void onProviderEnabled(String provider) Called when the provider is enabled by the user. – void onStatusChanged(String provider, int status, Bundle extras) Called when the provider status changes. Status can be OUT_OF_SERVICE, TEMPORARILY_UNAVAILABLE, AVAILABLE

LocationListener added to your LocationManger LocationManager myL = (LocationManager) getBaseContext().getSystemService(Context.LOCATION_SERVICE); myL.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, myLocationListener); – here Use a GPS provider, could be NETWORK_PROVIDER – minTime the minimum time interval for notifications, in milliseconds. This field is only used as a hint to conserve power, and actual time between location updates may be greater or lesser than this value. Here set to 0 – minDistance the minimum distance interval for notifications, in meters. Again set to 0 here. – myLocationListener is a the LocationListener to be called.

Example code A simple android program is provided on the website. It will display location information in a TextView. It also has a LocationListener. Use the ddms.bat in the tools directory to change the location info.

References Android (many links have mapactivity as well, skipped in lecture, we’ll come back to it) – CN/guide/topics/location/index.html – android.html – location- api/ napi – Controlling the android emulator – CN/guide/developing/tools/ddms.html#emulator-control

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