Ask for location permission during run-time, Andro

I have a very simple app which takes location data from Google's fused location provider API and displays it. Now, for Android M+, I want to ask for location permission during run-time. Below is some relevant code from my MainActivity.java file:

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

    if(checkAndRequestPermissions()) {
        // carry on the normal flow, as the case of  permissions  granted.
        mLatitudeTextView = (TextView) findViewById((R.id.latitude_textview));
        mLongitudeTextView = (TextView) findViewById((R.id.longitude_textview));

        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();

        mLocationManager = (LocationManager)this.getSystemService(Context.LOCATION_SERVICE);

        checkLocation(); //check whether location service is enable or not in your  phone
    }
}

private  boolean checkAndRequestPermissions() {
    int permissionLocation = ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION);


    List<String> listPermissionsNeeded = new ArrayList<>();

    if (permissionLocation != PackageManager.PERMISSION_GRANTED) {
        listPermissionsNeeded.add(Manifest.permission.ACCESS_FINE_LOCATION);
    }
    if (!listPermissionsNeeded.isEmpty()) {
        ActivityCompat.requestPermissions(this, listPermissionsNeeded.toArray(new String[listPermissionsNeeded.size()]), REQUEST_ID_MULTIPLE_PERMISSIONS);
        return false;
    }
    return true;
}

@Override
public void onRequestPermissionsResult(int requestCode,
                                       String permissions[], int[] grantResults) {
    Log.d(TAG, "Permission callback called-------");
    switch (requestCode) {
        case REQUEST_ID_MULTIPLE_PERMISSIONS: {

            Map<String, Integer> perms = new HashMap<>();
            // Initialize the map with both permissions
            perms.put(Manifest.permission.ACCESS_FINE_LOCATION, PackageManager.PERMISSION_GRANTED);
            // Fill with actual results from user
            if (grantResults.length > 0) {
                for (int i = 0; i < permissions.length; i++)
                    perms.put(permissions[i], grantResults[i]);
                // Check for both permissions
                if (perms.get(Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                    Log.d(TAG, "sms & location services permission granted");
                    // process the normal flow
                    mLatitudeTextView = (TextView) findViewById((R.id.latitude_textview));
                    mLongitudeTextView = (TextView) findViewById((R.id.longitude_textview));

                    mGoogleApiClient = new GoogleApiClient.Builder(this)
                            .addConnectionCallbacks(this)
                            .addOnConnectionFailedListener(this)
                            .addApi(LocationServices.API)
                            .build();

                    mLocationManager = (LocationManager)this.getSystemService(Context.LOCATION_SERVICE);

                    checkLocation(); //check whether location service is enable or not in your  phone
                    //else any one or both the permissions are not granted
                } else {
                    Log.d(TAG, "Some permissions are not granted ask again ");
                    //permission is denied (this is the first time, when "never ask again" is not checked) so ask again explaining the usage of permission
                    // shouldShowRequestPermissionRationale will return true
                    //show the dialog or snackbar saying its necessary and try again otherwise proceed with setup.
                    if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_FINE_LOCATION)) {
                        showDialogOK("Service Permissions are required for this app",
                                new DialogInterface.OnClickListener() {
                                    @Override
                                    public void onClick(DialogInterface dialog, int which) {
                                        switch (which) {
                                            case DialogInterface.BUTTON_POSITIVE:
                                                checkAndRequestPermissions();
                                                break;
                                            case DialogInterface.BUTTON_NEGATIVE:
                                                // proceed with logic by disabling the related features or quit the app.
                                                System.exit(1);
                                                break;
                                        }
                                    }
                                });
                    }
                    //permission is denied (and never ask again is  checked)
                    //shouldShowRequestPermissionRationale will return false
                    else {
                        explain("You need to give some mandatory permissions to continue. Do you want to go to app settings?");
                        //                            //proceed with logic by disabling the related features or quit the app.
                    }
                }
            }
        }
    }

}

private void showDialogOK(String message, DialogInterface.OnClickListener okListener) {
    new AlertDialog.Builder(this)
            .setMessage(message)
            .setPositiveButton("OK", okListener)
            .setNegativeButton("Cancel", okListener)
            .create()
            .show();
}
private void explain(String msg){
    final android.support.v7.app.AlertDialog.Builder dialog = new android.support.v7.app.AlertDialog.Builder(this);
    dialog.setMessage(msg)
            .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface paramDialogInterface, int paramInt) {
                    //  permissionsclass.requestPermission(type,code);
                    startActivity(new Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.parse("package:com.myapp.myapplication")));
                }
            })
            .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface paramDialogInterface, int paramInt) {
                    System.exit(1);
                }
            });
    dialog.show();
}

@Override
public void onConnected(Bundle bundle) {
    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.
        return;
    }

    startLocationUpdates();

    mLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);

    if(mLocation == null){
        startLocationUpdates();
    }
    if (mLocation != null) {

        // mLatitudeTextView.setText(String.valueOf(mLocation.getLatitude()));
        //mLongitudeTextView.setText(String.valueOf(mLocation.getLongitude()));
    } else {
        Toast.makeText(this, "Location not Detected", Toast.LENGTH_SHORT).show();
    }
}
protected void startLocationUpdates() {
    // Create the location request
    mLocationRequest = LocationRequest.create()
            .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
            .setInterval(UPDATE_INTERVAL)
            .setFastestInterval(FASTEST_INTERVAL);
    // Request location updates
    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.
        return;
    }
    LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient,
            mLocationRequest, this);
    Log.d("reque", "--->>>>");
}
private boolean checkLocation() {
    if(!isLocationEnabled())
        showAlert();
    return isLocationEnabled();
}

private void showAlert() {
    final AlertDialog.Builder dialog = new AlertDialog.Builder(this);
    dialog.setTitle("Enable Location")
            .setMessage("Your Locations Settings is set to 'Off'.\nPlease Enable Location to " +
                    "use this app")
            .setPositiveButton("Location Settings", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface paramDialogInterface, int paramInt) {

                    Intent myIntent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                    startActivity(myIntent);
                }
            })
            .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface paramDialogInterface, int paramInt) {

                }
            });
    dialog.show();
}

private boolean isLocationEnabled() {
    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    return locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER) ||
            locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
}

There are two problems in the above code as of now. First if the user does grants location permission, then nothing happens. No location data is displayed. Only when I restart the app I see the location data.

Second, if the user checks 'never ask again' and my explain() function runs then immediately after displaying the settings of the app, I get the message 'Sorry, My Application has stopped','OK','Cancel'. Whichever button I press I remain on the settings of the app and if I change the settings and press back button, then it also closes.

回答1:

Well You have to start the service in two cases:-

1) When user grant the location access.

2)When user already granted the permission after launching application again.

So you have to handle both the ways

Try this.

public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;

public boolean checkLocationPermission() {
    if (ContextCompat.checkSelfPermission(this,
            Manifest.permission. ACCESS_FINE_LOCATION)
            != PackageManager.PERMISSION_GRANTED) {

        // Should we show an explanation?
        if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                Manifest.permission. ACCESS_FINE_LOCATION)) {

            // Show an explanation to the user *asynchronously* -- don't block
            // this thread waiting for the user's response! After the user
            // sees the explanation, try again to request the permission.
            new AlertDialog.Builder(this)
                    .setTitle(R.string.title_location_permission)
                    .setMessage(R.string.text_location_permission)
                    .setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialogInterface, int i) {
                            //Prompt the user once explanation has been shown
                            ActivityCompat.requestPermissions(MainActivity.this,
                                    new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                                    MY_PERMISSIONS_REQUEST_LOCATION);
                        }
                    })
                    .create()
                    .show();


        } else {
            // No explanation needed, we can request the permission.
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission. ACCESS_FINE_LOCATION},
                    MY_PERMISSIONS_REQUEST_LOCATION);
        }
        return false;
    } else {
        return true;
    }
}

@Override
public void onRequestPermissionsResult(int requestCode,
                                       String permissions[], int[] grantResults) {
    switch (requestCode) {
        case MY_PERMISSIONS_REQUEST_LOCATION: {
            // If request is cancelled, the result arrays are empty.
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                // permission was granted, yay! Do the
                // location-related task you need to do.
                if (ContextCompat.checkSelfPermission(this,
                        Manifest.permission. ACCESS_FINE_LOCATION)
                        == PackageManager.PERMISSION_GRANTED) {


                    // do your stuff here
                }

            } else {

                // permission denied, boo! Disable the
                // functionality that depends on this permission.

            }
            return;
        }

    }
}

The in OnResume() do this

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

    if (checkLocationPermission()) {
       if (ContextCompat.checkSelfPermission(this,
           Manifest.permission. ACCESS_FINE_LOCATION)
           == PackageManager.PERMISSION_GRANTED) {
                  // do your stuff here

       }
    }

}

回答2:

if (ContextCompat.checkSelfPermission(getActivity(),
                    Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED || ContextCompat.checkSelfPermission(getActivity(),
                    Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                //Permission not Granted...
                requestPermissions(
                        new String[]{Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION},
                        Constant.RequestPermissions.LOCATIONS);

            } else {

                //Permission has been already Granted...

            }

And Add this listener to listen User's action on that permission request -

@Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[],
                                           @NonNull int[] grantResults) {
        switch (requestCode) {
            case Constant.RequestPermissions.LOCATIONS:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED
                        && grantResults[1] == PackageManager.PERMISSION_GRANTED) {

                    // User Allows Permission access


                } 
                else 
                {

                    // User denies Permission access

                }
    }