Android GoogleMaps myLocation Permission

Question

With the more recent version of Android... you are supposed to check if the user has given you permission before you use their location info. I've gone through the android docs and this is the code I've come up with.

I'm checking to see if the user has given permission, if they haven't yet... then we ask and then there's a callback function on the results and so on.

I've stepped through the code many times and everything seems to be working fine EXCEPT: when I finally try to programmatically get the user's location with fusedLocationApi.getLastLocation ... it returns NULL!!

I've re-uploaded the code I have.

Anyone who can figure this out and it actually works for me, you can have all my rep score...

package com.example.greg.rightnow;


import android.content.pm.PackageManager;
import android.location.Location;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.support.v4.content.ContextCompat;
import android.Manifest;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.Api;
import com.google.android.gms.common.api.GoogleApiClient.ConnectionCallbacks;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.PendingResult;
import com.google.android.gms.common.api.Status;
import com.google.android.gms.drive.Drive;
import com.google.android.gms.location.LocationServices;
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.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.plus.Plus;

import java.io.FileDescriptor;
import java.io.PrintWriter;
import java.util.concurrent.TimeUnit;

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback, ConnectionCallbacks {

    private GoogleApiClient mGoogleApiClient;
    private GoogleMap mMap;
    private Location mLastLocation;


    @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);

        // Create an instance of GoogleAPIClient.
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addApi(Drive.API)
                .addApi(Plus.API)
                .addScope(Drive.SCOPE_FILE)
                .addConnectionCallbacks(this)
        //        .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();


    }


    @Override
    public void onConnected(@Nullable Bundle bundle) {

        }





    protected void onStart() {
        mGoogleApiClient.connect();
        super.onStart();
    }

    protected void onStop() {
        mGoogleApiClient.disconnect();
        super.onStop();
    }




    /**
     * Manipulates the map once available.
     * This callback is triggered when the map is ready to be used.
     * This is where we can add markers or lines, add listeners or move the camera. In this case,
     * we just add a marker near Sydney, Australia.
     * If Google Play services is not installed on the device, the user will be prompted to install
     * it inside the SupportMapFragment. This method will only be triggered once the user has
     * installed Google Play services and returned to the app.
     * Manifest.permission.ACCESS_FINE_LOCATION
     */

    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           String permissions[], int[] grantResults) {


        if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == grantResults[0]) {
            mMap.setMyLocationEnabled(true);
        }


        mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);

        LatLng myLat = new LatLng(mLastLocation.getLatitude(), mLastLocation.getLongitude());
        // Add a marker in Sydney and move the camera
        LatLng sydney = new LatLng(-34, 151);
        mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
        mMap.moveCamera(CameraUpdateFactory.newLatLng(myLat));


    }





    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
                == 0) {

            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 1);

        }

        else if(ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION) ==-1) {
            mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);

            LatLng myLat = new LatLng(mLastLocation.getLatitude(), mLastLocation.getLongitude());
            // Add a marker in Sydney and move the camera
            LatLng sydney = new LatLng(-34, 151);
            mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
            mMap.moveCamera(CameraUpdateFactory.newLatLng(myLat));


        }

    }

    @Override
    public void onConnectionSuspended(int i) {

    }
}

You'll notice that I had to comment out this line:

 //   .addOnConnectionFailedListener(this)

If I uncomment this... the 'this' gets underlined in red and I get an error saying "... in Builder cannot be applied to com.example.greg.MapsActivity etc"

Answer 1

HERE WAS THE PROBLEM: Android Emulator

Scroll down to "Working with the Extended Controls, Settings, and Help".
Long story short: IF YOU ARE USING AN EMULATOR, YOU HAVE TO FAKE YOUR LOCATION DATA!!!!! The emulator doesn't support wifi (or as far as I can tell, GPS data either).

Click on your "phone" (your emulator) to make sure it's selected, and press ctrl+shift+L Type in any location you want and click "Send" and viola... you'll have a location. I knew something was up when GoogleMaps on my emulator wasn't even working. I would search for directions and it would say "Waiting for Location" and nothing would happen.

Good freaking riddance.

Answer 2

After checking the permissions with ContextCompat.checkSelfPermission, if it's not granted, you can request for it. From the documentation:

Also, you need to deal with connection failures when using GoogleApiClient (documentation). In your code, the connection was failing and you weren't managing it on onConnectionFailed.

And finally, I have removed the following from your code (this was causing a connect failure and are not neccesary to use LocationServices and get the last location):

.addApi(Drive.API)
.addApi(Plus.API)
.addScope(Drive.SCOPE_FILE)

Here is a working example:

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback, GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener {
    private static final int FINE_LOCATION_PERMISSION_REQUEST = 1;
    private static final int CONNECTION_RESOLUTION_REQUEST = 2;
    private GoogleApiClient mGoogleApiClient;
    private GoogleMap mMap;
    private Location mLastLocation;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);

        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

        buildGoogleAPIClient();
    }

    @Override
    protected void onResume() {
        super.onResume();

        buildGoogleAPIClient();
    }

    private void buildGoogleAPIClient() {
        if (mGoogleApiClient == null) {
            mGoogleApiClient = new GoogleApiClient.Builder(this)
                    .addConnectionCallbacks(this)
                    .addOnConnectionFailedListener(this)
                    .addApi(LocationServices.API)
                    .build();
        }
    }

    @Override
    public void onConnected(@Nullable Bundle bundle) {
        findLocation();
    }

    protected void onStart() {
        mGoogleApiClient.connect();
        super.onStart();
    }

    protected void onStop() {
        mGoogleApiClient.disconnect();
        super.onStop();
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
    }

    @Override
    public void onConnectionSuspended(int i) {
        Toast.makeText(this, "Connection suspended", Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onConnectionFailed(@NonNull final ConnectionResult connectionResult) {
        if (connectionResult.hasResolution()) {
            try {
                connectionResult.startResolutionForResult(this, CONNECTION_RESOLUTION_REQUEST);
            } catch (IntentSender.SendIntentException e) {
                // There was an error with the resolution intent. Try again.
                mGoogleApiClient.connect();
            }
        } else {
            Dialog dialog = GooglePlayServicesUtil.getErrorDialog(connectionResult.getErrorCode(), this, 1);
            dialog.show();
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode,
                                    Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == CONNECTION_RESOLUTION_REQUEST && resultCode == RESULT_OK) {
            mGoogleApiClient.connect();
        }
    }

    private void findLocation() {
        if (ContextCompat.checkSelfPermission(this,
                Manifest.permission.ACCESS_FINE_LOCATION)
                != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                    FINE_LOCATION_PERMISSION_REQUEST);
        } else {
            mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);

            LatLng myLat = new LatLng(mLastLocation.getLatitude(), mLastLocation.getLongitude());
            // Add a marker in Sydney and move the camera
            LatLng sydney = new LatLng(-34, 151);
            mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
            mMap.moveCamera(CameraUpdateFactory.newLatLng(myLat));
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           String permissions[], int[] grantResults) {
        switch (requestCode) {
            case FINE_LOCATION_PERMISSION_REQUEST: {
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    findLocation();
                }
            }
        }
    }
}