Android Working With FusedLocation LastLocation

Building Location Based Based Application , Getting location data for your app based on combined signals from the device sensors using a battery-efficient API , The location APIs available in Google Play services facilitate adding location awareness to your app with automated location tracking.

The fused location provider is a location API in Google Play services that intelligently combines different signals to provide the location information that your app needs. fused location provider API is Simple, battery-efficient location API for Android .


1. Gradle


Add Google Service Dependency to app level gradle .

file : build.gradle(App Level)
dependencies {

    implementation "com.google.android.gms:play-services-location:18.0.0"
}


2. AndroidManifest


Add Location Permission to Android Manifest .

file : AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.tutorialsbuzz.mylocation">

    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

   ..........
   ..........
   ..........

</manifest>


3. XML Layout


Create XML Layout and Add TextView and Button to it .

file : activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:textSize="22sp" />

    <Button
        android:id="@+id/fetchMyLocation"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:text="Fetch My Location"
        android:textSize="20sp" />

</LinearLayout>


4. Activity


  1. Create MainActivity class which extends AppCompatActivity and inside onCreate function set the content of Activity with Above define XML Layout .
  2. On Button click call fetch Current Location Details .
  3. Before Getting Location Details using FusedLocation API , Request for App Location permission once the permission is granted update UI with Latitude and Longitude .

Get Last Known Location

  • Create an instance of the Fused Location Provider Client. 
  • Once you have created the Location Services client you can get the last known location of a user's device. When your app is connected to these you can use the fused location provider's getLastLocation() method to retrieve the device location.
mFusedLocationClient.lastLocation.addOnCompleteListener(this) { task ->

		val location: Location? = task.result

		if (location == null) {

			// Create Location Request
			
		} else {
			// Update Ui 
            // Lat Lng ( location.latitude, location.longitude )
		   
		}		
	}

Making Location Request .

If the returned location  is null then make another location request update on locationProvider Client , requestLocationUpdates function takes locationRequest and a Callback (Receives Location) .

The following code snippet illustrates the request and callBack on Update :

// 1. Create Location Request
val locationRequest = LocationRequest.create().apply {
	interval = 10000
	fastestInterval = 5000
	priority = LocationRequest.PRIORITY_HIGH_ACCURACY
}

// 2. Request for location update
mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this)
mFusedLocationClient.requestLocationUpdates(
	locationRequest, mLocationCallback,
	Looper.myLooper()
)		

//3. CallBack for location update Request
mLocationCallback = object : LocationCallback() {
	override fun onLocationResult(locationResult: LocationResult) {
		// Update UI With Lat Lng 
		// locationResult.lastLocation.latitude
		//	locationResult.lastLocation.longitude
	}
}

file : MainActivity.kt
package com.tutorialsbuzz.mylocation

class MainActivity : AppCompatActivity() {

    private lateinit var mFusedLocationClient: FusedLocationProviderClient
    private lateinit var mLocationCallback: LocationCallback

    val PERMISSION_ID = 42

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this)

        fetchMyLocation.setOnClickListener({
            getMyCurrenLocation()
        })

        //CallBack for location update Request
        mLocationCallback = object : LocationCallback() {
            override fun onLocationResult(locationResult: LocationResult) {
                // Update UI With Lat Lng
                updateUIWithLatLng(
                    locationResult.lastLocation.latitude,
                    locationResult.lastLocation.longitude
                )
            }
        }

    }

    fun updateUIWithLatLng(latitude: Double, longitude: Double) {
        val textLabel = " Latitude: $latitude \n Longitude: $longitude "
        textView.text = textLabel
    }

    fun requestPermissions() {
        ActivityCompat.requestPermissions(
            this,
            arrayOf(
                Manifest.permission.ACCESS_COARSE_LOCATION,
                Manifest.permission.ACCESS_FINE_LOCATION
            ),
            PERMISSION_ID
        )
    }

    fun getMyCurrenLocation() {

        if (ActivityCompat.checkSelfPermission(
                this, Manifest.permission.ACCESS_FINE_LOCATION
            ) != PackageManager.PERMISSION_GRANTED &&
            ActivityCompat.checkSelfPermission(
                this, Manifest.permission.ACCESS_COARSE_LOCATION
            ) != PackageManager.PERMISSION_GRANTED
        ) {
            //request for location permission
            requestPermissions()

        } else {

            mFusedLocationClient.lastLocation.addOnCompleteListener(this) { task ->

                val location: Location? = task.result

                if (location == null) {

                    // Create Location Request
                    val locationRequest = LocationRequest.create().apply {
                        interval = 10000
                        fastestInterval = 5000
                        priority = LocationRequest.PRIORITY_HIGH_ACCURACY
                    }

                    // Request for location update
                    mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this)
                    mFusedLocationClient.requestLocationUpdates(
                        locationRequest, mLocationCallback,
                        Looper.myLooper()
                    )

                } else {
                    // Update Ui With Lat Lng
                    updateUIWithLatLng(location.latitude, location.longitude)
                }
            }
        }
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<String>,
        grantResults: IntArray
    ) {
        if (requestCode == PERMISSION_ID) {
            if ((grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED)) {
                //Permission Granted
                getMyCurrenLocation()
                showToast("Permission Granted:")
            } else {
               // Permission Denied
                showToast("Permission Denied:")
            }
        }
    }

    fun showToast(msg: String) {
        Toast.makeText(this@MainActivity, msg, Toast.LENGTH_LONG).show()
    }
}


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