Develop Reference

How to gain permission to get GPS location in Android

I am new to Android and in my current project I am trying to retrieve location using GPS. The code for obtaining the location is in a separate non-activity class, because the fragment where I display the coordinates is crammed.
I have tried to use the guidelines from developer.android.com but I can't get any permission prompt, and when I press the button in the fragment, I only get the default 0-values for latitude and longitude.
I have provided the permissions in the manifest:
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
The GPS locator class:
public class LocationProvider implements ActivityCompat.OnRequestPermissionsResultCallback {
private static final int PERMISSION_REQUEST_LOCATION = 1;
private Activity activity;
Location gps_loc;
Location final_loc;
double longitude;
double latitude;
private LocationManager locationManager;
public LocationProvider(Activity activity) {
this.activity =activity;
locationManager = (LocationManager) activity.getSystemService(Context.LOCATION_SERVICE);
}
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull int[] grantResults) {
if (requestCode == PERMISSION_REQUEST_LOCATION) {
// Request for permission.
if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
getLocation();
} else {
requestLocationPermission();
}
}
}
private void getLocation() {
// Check if the permission has been granted
if (ActivityCompat.checkSelfPermission(activity, Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
gps_loc = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (gps_loc != null) {
Log.v("Loc_provider",gps_loc.toString());
final_loc = gps_loc;
latitude = final_loc.getLatitude();
longitude = final_loc.getLongitude();
}
} else {
requestLocationPermission();
}
}
private void requestLocationPermission() {
ActivityCompat.requestPermissions(activity,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, PERMISSION_REQUEST_LOCATION);
}
public String getCoordinates() {
return latitude + " "+ longitude;
}
}
The code in the fragment:
FloatingActionButton fab=view.findViewById(R.id.floatingActionButton);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
locProvider=new LocationProvider(requireActivity());
gpsCoordinates.setText(locProvider.getCoordinates());
}
});
Tips and solutions for fixing the code are most welcome.
UPDATE 1:
I moved the code in the fragment instead, so that it looks like below:
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (!checkIfAlreadyhavePermission()) {
requestPermissions(new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 1);
} else {
gps_loc = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
gpsCoordinates.setText(getCoordinates());
}
}
});
private String getCoordinates() {
if (gps_loc != null) {
Log.v("Loc_provider", gps_loc.toString());
final_loc = gps_loc;
latitude = gps_loc.getLatitude();
longitude = gps_loc.getLongitude();
}
return latitude + " " + longitude;
}
private boolean checkIfAlreadyhavePermission() {
int result = ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION);
return result == PackageManager.PERMISSION_GRANTED;
}
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull int[] grantResults) {
switch (requestCode) {
case PERMISSION_REQUEST_LOCATION: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
//Log.v("Grant_Results", String.valueOf(grantResults[0]));
Toast.makeText(getActivity(), "permission granted", Toast.LENGTH_LONG).show();
gpsCoordinates.setText(getCoordinates());
} else {
Toast.makeText(getActivity(), "permission denied", Toast.LENGTH_LONG).show();
}
break;
}
}
}
I now get the permission prompt, but the location still doesn't update (I get 0).

Please note:
Saving an Activity object is not recommended this may cause memory leaks. Activity may be destroyed and recreated (for example when screen orientation changes). Holding a reference to the old activity will cause you problems.
Implementing the ActivityCompat.OnRequestPermissionsResultCallback interface does nothing. Your method will never be called. You will have to call it explicitly from the activity.
You have not requested permission, so your permission prompt will never be shown and the default value of double that is 0 will get returned. You need to call your getLocation() method so that the control falls on the else block and your permission prompt is shown
I recommend you handle permission in the activity. Have the activity get the coordinates for the location. You can have the activity implement an interface, say LocationFetcher, with a method getCoordinates(). You can then call this in the fragment like so:
LocationFetcher locationFetcher = (LocationFetcher) activity;
gpsCoordinates.setText(locationFetcher.getCoordinates());

Fixed by implementing LocationListener in Fragment and then adding
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 400, 1, this);
in onRequestPermissionsResult().

last known location is always 0 [duplicate]

This question already has answers here:
Location is empty at the start
(5 answers)
Closed 3 years ago.
Inspite of my best effort, I am unable to get my location correct. This is my main.java
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
SectionsPagerAdapter sectionsPagerAdapter = new SectionsPagerAdapter(this, getSupportFragmentManager());
ViewPager viewPager = findViewById(R.id.view_pager);
viewPager.setAdapter(sectionsPagerAdapter);
//new SecondFragment();
//TabLayout tabs = findViewById(R.id.tabs);
//tabs.setupWithViewPager(viewPager);
FloatingActionButton fab = findViewById(R.id.fab);
FontDrawable drawable = new FontDrawable(this, R.string.fa_plus_solid, true, false);
drawable.setTextColor(ContextCompat.getColor(this, android.R.color.white));
fab.setImageDrawable(drawable);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
//Check permission
if (ContextCompat.checkSelfPermission(getApplicationContext(),
android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED &&
ActivityCompat.checkSelfPermission(getApplicationContext(),
android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this,
new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION,
android.Manifest.permission.ACCESS_COARSE_LOCATION}, 101);
FusedLocationProviderClient mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
mFusedLocationClient.getLastLocation()
.addOnSuccessListener(this, new OnSuccessListener<Location>() {
#Override
public void onSuccess(Location location) {
// Got last known location. In some rare situations this can be null.
if (location != null) {
latlang.Lat =location.getLatitude();
latlang.Lang =location.getLongitude();
}
}
});
}
}
}
the latlang is defined in another file as:
public class latlang {
public static double Lat;
public static double Lang;
}
If I hardcode the value here in latlang, everything is fine. But, of course I want the value of last known location.
Kindly help.

The problem is that you try to get the location before the permission is granted.
After calling requestPermissions() you immediately try to get location while the permission dialog is being displayed which means that the code that gets the location is being executed while you are seeing the permission dialog. This is why there is onRequestPermissionsResult function in activity that reports only after the user is done with permissions dialog.
You will need to get the location in onRequestPermissionsResult().
Second problem in your code is that you are only getting location when the permission is not granted. Your code does not handle the case when permission is already granted.
Here is how you would solve this:
#Override
protected void onCreate(Bundle savedInstanceState) {
if (ContextCompat.checkSelfPermission(getApplicationContext(),
android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED &&
ActivityCompat.checkSelfPermission(getApplicationContext(),
android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this,
new String[] {
android.Manifest.permission.ACCESS_FINE_LOCATION,
android.Manifest.permission.ACCESS_COARSE_LOCATION
}, 101);
} else {
fetchLocation();
}
}
#Override
public void onRequestPermissionsResult(int requestCode,
String[] permissions, int[] grantResults) {
switch (requestCode) {
case 101:
{
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0 &&
(grantResults[0] == PackageManager.PERMISSION_GRANTED ||
grantResults[1] == PackageManager.PERMISSION_GRANTED)) {
// permission was granted
fetchLocation()
} else {
Show some error
}
return;
}
// other 'case' lines to check for other
// permissions this app might request.
}
}
public void fetchLocation() {
FusedLocationProviderClient mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
mFusedLocationClient.getLastLocation()
.addOnSuccessListener(this, new OnSuccessListener < Location > () {
#Override
public void onSuccess(Location location) {
// Got last known location. In some rare situations this can be null.
if (location != null) {
latlang.Lat = location.getLatitude();
latlang.Lang = location.getLongitude();
}
}
});
}
Basically, Create a separate function that gets the location. You will call this function from 2 places. First is in onCreate when the permission is granted, and second in onPermissionResult. Don't forget to handle permission errors.

Annotations are not allowed here when moving to a separated class

I try to separate my Location finding code from the Main activity, so I moved the entire related code to a different class:
(*I began with Android today and Java is also fairly new to me, so sorry if this is a silly question)
public class LocationCode {
private LocationCallback mLocationCallback;
private TextView tv;
private Button button;
private FusedLocationProviderClient mFusedLocationClient;
private final int MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 5;
public LocationCode (Context context, TextView textView, Button btn) {
LocationRequest mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(10000);
mLocationRequest.setFastestInterval(5000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
this.tv = textView;
this.button = btn;
mLocationCallback = new LocationCallback() {
#Override
public void onLocationResult(LocationResult locationResult) {
if (locationResult == null) {
return;
}
for (Location location : locationResult.getLocations()) {
// Update UI with location data
Double latDouble = location.getLatitude();
String latString = latDouble.toString();
Double longtDouble = location.getLongitude();
String longtString = longtDouble.toString();
tv.setText(latString + " " + longtString);
}
}
};
#Override
public void onRequestPermissionsResult ( int requestCode,
String permissions[], int[] grantResults){
TextView tv1 = this.tv;
Button button = this.button;
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
//
} else {
mFusedLocationClient.requestLocationUpdates(mLocationRequest, mLocationCallback,
null /* Looper */);
}
} else {
// permission denied, boo! Disable the
// functionality that depends on this permission.
tv1.setText("Not Granted!");
button.setVisibility(View.VISIBLE);
}
return;
}
// other 'case' lines to check for other
// permissions this app might request.
}
}
}
}
From MainActivity I should probably call this code like so:
LocationCode locationCode = new LocationCode(this, textView, Button);
But I get the following error on the second #Override (The one above public void onRequestPermissionsResult). Why is that, and how can I fix it? Or there is a better way to separate this code to make it look more neat in the MainActivity?

Adding location permissions on marshmallow

I am writing a code to get lastknownlocation from location manager and this prompted me to add runtime permissions.
Here is my code:
public class MainActivity extends AppCompatActivity implements LocationListener {
LocationManager locationManager;
String provider;
private final int MY_PERMISSIONS_REQUEST_CODE=1;
Location location;
Boolean isPermissionGranted=false;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
provider = locationManager.getBestProvider(new Criteria(), false);
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
requestPermissions(new String[]{Manifest.permission.ACCESS_FINE_LOCATION,Manifest.permission.ACCESS_COARSE_LOCATION},MY_PERMISSIONS_REQUEST_CODE);
}
// return;
}
}
public void getlastknownposition()
{
}
#Override
public void onLocationChanged(Location location) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onProviderDisabled(String provider) {
}
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if(requestCode == MY_PERMISSIONS_REQUEST_CODE)
{
if(grantResults[0]==PackageManager.PERMISSION_GRANTED && grantResults[1]==PackageManager.PERMISSION_GRANTED){
Toast.makeText(MainActivity.this," granted "+grantResults[0]+"granted2"+grantResults[1], Toast.LENGTH_SHORT).show();
location = locationManager.getLastKnownLocation(provider);}
}
}
}
I am still getting an error "Call requires permission which may be rejected by user: code should explicitly check to see if permission is available (with checkPermission) or explicitly handle a potential SecurityException
in onRequestPermissionsResult on line location = locationManager.getLastKnownLocation(provider);

Put some braces around the second if in onPermissionsResult =)
if(requestCode == MY_PERMISSIONS_REQUEST_CODE){
if(grantResults[0]==PackageManager.PERMISSION_GRANTED && grantResults[1]==PackageManager.PERMISSION_GRANTED){
Toast.makeText(MainActivity.this," granted "+grantResults[0]+"granted2"+grantResults[1], Toast.LENGTH_SHORT).show();
location = locationManager.getLastKnownLocation(provider);
} else {
//TODO handle user saying NO! :)
}
}
Tip: if you request FINE_LOCATION you don't need COARSE, it already includes it.

Replace the line
location = locationManager.getLastKnownLocation(provider);
with
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED
&& ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED)
{
location = locationManager.getLastKnownLocation(provider);
}

Code Returns from If(ActivityCompat.checkSelfPermission) segment

Hello Everyone I am creating Navigation Application using Android Studio and getting this error while doing.
My Code Stops in if(ActivityCompat.checkSelfPermission) segment. Here i have toast statement. I have already provided COARSE_LOCATION, FINE_LOCATION and INTERNET permission in AndroidManifest file.
Following code given.
public class Second extends Activity implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener {
//Declaring Class Objects
Location location;
LocationManager lm;
GoogleApiClient googleApiClient;
//Data type for storing value of Longitude and Latitude
private double fromLongitude;
private double fromLatitude;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.second);
googleApiClient = new GoogleApiClient.Builder(this).addApi(LocationServices.API).addConnectionCallbacks(this).addOnConnectionFailedListener(this).build();
getLocation();
}
private void getLocation() {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
Toast.makeText(this,"Issue with permission",Toast.LENGTH_LONG).show();
return;
}
Location location = LocationServices.FusedLocationApi.getLastLocation(googleApiClient);
fromLatitude = location.getLatitude();
fromLongitude = location.getLongitude();
Toast.makeText(this,String.valueOf(fromLatitude)+" "+String.valueOf(fromLongitude),Toast.LENGTH_LONG).show();
}
//Starting Google API Client
#Override
protected void onStart() {
googleApiClient.connect();
super.onStart();
}
//Stopping Google API Client
#Override
protected void onStop() {
googleApiClient.disconnect();
super.onStop();
}
#Override
public void onConnected(Bundle bundle) {
}
#Override
public void onConnectionSuspended(int i) {
}
#Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
}
This prints "Issue with Permission", that i have toast in if segment.

try
this
checkSelfPermission(Permission) to check is permission is granted already or not.
requestPermissions(String[] permissions, int requestCode) to request for permissions.
onRequestPermissionsResult(int permsRequestCode, String[] permissions, int[] grantResults) to check for results whether permission is granted or not.
Request Permission like this
private void askForPermission() {
int hasWriteContactsPermission = checkSelfPermission(Manifest.permission.CAMERA);
if (hasWriteContactsPermission != PackageManager.PERMISSION_GRANTED) {
if(!shouldShowRequestPermissionRationale(Manifest.permission.CAMERA)) {
showMessageOKCancel("You need to allow access to Contacts",
new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
requestPermissions(new String[]{Manifest.permission.CAMERA},REQUEST_CODE_ASK_PERMISSIONS);
}
});
return;
}
requestPermissions(new String[] {Manifest.permission.CAMERA},
REQUEST_CODE_ASK_PERMISSIONS);
return;
}
}
Refer here to understand in detail https://coderzpassion.com/android-new-runtime-permissions/