Design
How do I get Google Maps Displaying current location
The Google Map API key needs to be generated to display and place a marker at the user current location. Along with that, we also need to implement some interfaces and their callbacks methods.
Callback methods in Google Map:
OnMapRreadyCallback:
- Invoked when its instance is set on the MapFragment object.
- When the map is ready to be used, the onMapReady(GoogleMap) method of the OnMapReadyCallback interface is called.
- Markers, listeners, and other attributes can be added in the onMapReady(GoogleMap) method.
LocationListener:
- Used to receive a notification when the device location has changed.
- When the location has changed, the LocationChanged(Location) is called which is an abstract method of LocationListener.
GoogleApiClient.ConnectionCallbacks:
- When the device is to be connected and disconnected, the callbacks methods onConnected(Bundle) and onConnectionSuspended(int) of this interface are called.
GoogleApiClient.OnConnectionFailedListener:
- When there is an error in connecting the device to the service, the callbacks method onConnectionFailed(ConnectionResult) of this interface is called.
setMyLocationEnabled() method:
Used to enable the location layer, to allow the device to interact with the current location.
Example of Google Map Displaying Current Location:
In the below example, we are using the Google Map to display the current location of the device.
activity_maps.xml:
In the activity_maps.xml file, we will add a SupportMapFragment in the fragment.
build.gradle:
In the build.gradle file, we will add the below dependencies.
apply plugin: 'com.android.application'
android {
compileSdkVersion 28
defaultConfig {
applicationId "com.example.mapapp"
minSdkVersion 23
targetSdkVersion 28
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'com.google.android.gms:play-services-maps:11.8.0'
implementation 'com.google.android.gms:play-services-location:11.8.0'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
} |
MapsActivity.java:
In the MapsActivity.java file, we will add the below code.
package com.example.mapapp;
import android.os.Build;
import androidx.fragment.app.FragmentActivity;
import android.os.Bundle;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.location.LocationServices;
import android.location.Location;
import android.Manifest;
import android.content.pm.PackageManager;
import androidx.core.content.ContextCompat;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback,
LocationListener,GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener{
private GoogleMap mMap;
Location mLastLocation;
Marker mCurrLocationMarker;
GoogleApiClient mGoogleApiClient;
LocationRequest mLocationRequest;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
}
else {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
}
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API).build();
mGoogleApiClient.connect();
}
@Override
public void onConnected(Bundle bundle) {
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(1000);
mLocationRequest.setFastestInterval(1000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onLocationChanged(Location location) {
mLastLocation = location;
if (mCurrLocationMarker != null) {
mCurrLocationMarker.remove();
}
//Place current location marker
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title("Current Position");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
mCurrLocationMarker = mMap.addMarker(markerOptions);
//move map camera
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomTo(11));
//stop location updates
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
} |
AndroidManifest.xml:
To access device functionality in Android devices having Android 6.0 (Marshmallow) or later, we need some permission at runtime. To access device location, we added a runtime permission Manifest.permission.ACCESS_FINE_LOCATION, in the MapsActivity.java file. Now, we will add the below user-permission in AndroidManifest.xml file. The checkSelfPermission() method is used to check the runtime permission. It returns PackageManager.PERMISSION_GRANTED or PackageManager.PERMISSION_DENIED. The app proceeds for operation only when the permission is granted.
Required Permission:
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