locate

A Flutter plugin to work with Android Location Services.

Important Points ::

  • First of all, this flutter plugin doesn't work with IOS Location Service. Only Android Location Service is supported.
  • AndroidX enabled.
  • Kotlin(1.3.21) is used for implementation of platform side.
  • Google Play Service Location is used to get precise location using both cellular network and GPS.
  - AndroidX Core library used for backward compatibility.
  • CompileSDK and TargetSDK both are v28.

How to use it ???

Locate class has a singleton based architecture i.e. only a single instance can be created at a time. This class has four important methods that you'll be mostly using, which are as follows.

requestLocationPermission() :

  • At the beginning try calling requestLocationPermission(), to check whether location permission is avaible not not.
  • This method takes one optional positional argument provider, which defaults to gps.
  • I'd recommend you to use ACCESS_FINE_LOCATION in your app to get precise location data.
  • So, better you just don't pass any argument to requestLocationPermission().
  • After it completes in async fashion, this returns a bool.
  • If you get true, this means user has permitted you to access FINE_LOCATION of Android Device.
  • Else good luck to you ;)

enableLocation() :

  • So, if you get true, then lets go, to invoke enableLocation(), so that we can request user to enable location of device.
  • This also completes in async fashion and then returns true or false based on the result of the Activity.

startLocationUpdate() :

  • If we get true, we're good to call startLocationUpdate().
  • Well this method takes two optional positional parameters.
  • Imagine you have ACCESS_FINE_LOCATION permission for your app, then it'd be always better to invoke startLocationUpdate() as below :
    startLocationUpdate(locationServiceProvider: LocationServiceProvider.GMSBasedLocation);
  • Where LocationServiceProvider is a class holding two const properties : GMSBasedLocation = '0'; & LocationManagerBasedLocation = '1';

  • For using GooglePlayService based Location use LocationServiceProvider.GMSBasedLocation.

  • And for android.location.LocationManager based Location use LocationServiceProvider.LocationManagerBasedLocation.

  • Remember it's required to have ACCESS_FINE_LOCATION permission in order to user PlayService based Location using FusedLocationProviderClient.

  • If you're satisfied with ACCESS_COARSE_LOCATION, then request for that permission using

  - Well LocationProvider is also a class with two properties.

class LocationProvider { static const String Network = 'network'; static const String GPS = 'gps'; }

  - After that invoke **startLocationUpdate()** as follows for only network based Location Data.
startLocationUpdate(locationServiceProvider: LocationServiceProvider.LocationManagerBasedLocation, locationProvider: LocationProvider.Network);
  
  - You could also use it as follows, to use platform based LocationManager and **ACCESS_FINE_LOCATION** combination.

startLocationUpdate(locationServiceProvider: LocationServiceProvider.LocationManagerBasedLocation, locationProvider: LocationProvider.GPS);

  
  - If you take a look at implementation of **startLocationUpdate(){}**, you could find out, that I've registered an EventChannel here, which sets a flow of LocationData Update from Platform Level to Locate class.
  - Locate has a private method **_onData(dynamic event){}**, which gets invoked everytime App receive a Location Update from Platform.
  - This method extracts location data and stores current location info in an instance of **MyLocation class**.
  - If some error occurs, **_onError(dynamic error){}** gets invoked.
  
  
  #### How to get this Location Data in you app's StateFulWidget Class and update that widget in dynamic fashion by calling *setState()* ??
  
   So I've added another *abstract class LocationDataCallBack*, which has *onData(Map<String, String> myLocatoin){}*,
  that needs to be overridden wherever we implement **LocationDataCallBack**.
  
  - In example app's, [main.dart](https://github.com/itzmeanjan/locate/blob/master/example/lib/main.dart), I've implemented LocationDataCallBack in the class which extends State class.
  - Now we can simply take the data from the Map<String, String> and update UI.
  - Sample implementation of **onData**
@override

void onData(Map<String, String> myLocation) { setState(() { myText = 'Current Location : ${myLocation'longitude'}, ${myLocation'latitude'}\nUpdated at : ${DateTime.fromMillisecondsSinceEpoch(int.parse(myLocation'time', radix: 10)).toString()}'; }); }

  
  ### stopLocationUpdate() :
  
  - Now it's time to stop Location service. Lets call **stopLocationUpdate()**. And we're good to go.
  
  - Always invoke methods in order while requesting Location Data using Locate.
  
  - Follow the sequence **requestLocationPermission()** -> **enableLocation()** -> **startLocationUpdate()** -> **stopLocationUpdate()**.
  
  - Now you might ask me one question, **how am I supposed to initialize Locate class ?**
  - In **initState()** of your StateFulWidget, where you implemented **LocationDataCallBack**, just create an instance of Locate class by invoking **Locate(this)**.
  - Locate's constructor takes an instance of **LocationDataCallBack**.
  - Because that's what gets callbacked when new location data is available.
  - So it was simple, was't it ???
  
## Example App ::

  Example App written using **locate** can be found [here](https://github.com/itzmeanjan/locate/tree/master/example).


## Getting Started ::

For help getting started with Flutter, view our 
[online documentation](https://flutter.io/docs), which offers tutorials, 
samples, guidance on mobile development, and a full API reference.

## Courtesy ::

Last but not least, thanks to [flutter](http://flutter.dev), [Dartlang](http://dartlang.org/) and all of those persons who were somehow involved in developing such a great ecosystem, which has made the trouble of developing multiplatform apps significantly lesser.


Hope it was helpful :)

Libraries

locate
my_location