Runtime permissions handling

MainActivity.java

package com.example.runtime_permissions;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;

import android.Manifest;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;

import java.util.HashMap;

public class MainActivity extends AppCompatActivity {
    private LocationManager lm;

    private String[] requiredPermissions = new String[]{
            // Permissions to request - should be added in the manifest
            Manifest.permission.ACCESS_FINE_LOCATION,
            Manifest.permission.ACCESS_COARSE_LOCATION
    };

    private HashMap<String, Toast> toasts = new HashMap<>();

    private final int LOCATION_PERMISSIONS_REQUEST_CODE = 123;

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

        lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

        toasts.put(
                "LocationPermissionsError",
                Toast.makeText(this, "Location permissions denied", Toast.LENGTH_SHORT)
        );

        setupLocationListener();
    }


    /**
     * Check permissions are accepted or request them
     * @return boolean
     */
    private boolean checkIfHasPermissions() {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) return true;

        for (String permission : requiredPermissions)
            if (ActivityCompat.checkSelfPermission(this, permission) != PackageManager.PERMISSION_GRANTED)
                return false;

        return true;
    }

    /**
     * Request the required permissions for the app
     */
    private void requestPermissions() {
        // Request code allows this to be identified in onRequestPermissionsResult
        ActivityCompat.requestPermissions(this, requiredPermissions, LOCATION_PERMISSIONS_REQUEST_CODE);
    }

    /**
     * Handles permissions results for LOCATION_PERMISSIONS_REQUEST
     * @param grantResults int[] Permissions that have been granted
     */
    @SuppressLint("LongLogTag")
    private void handleLocationPermissionsResult(int[] grantResults) {
        boolean granted = true;
        if (grantResults.length > 0) for (int result : grantResults)
            if (result != PackageManager.PERMISSION_GRANTED) {
                granted = false;
                break;
            }
        Log.d("MainActivity::onRequestPermissionsResult", "Permissions granted: " + granted);
        if (granted) setupLocationListener();
        else toasts.get("LocationPermissionsError").show();
    }

    /**
     * onRequestPermissions Result callback
     * @param requestCode   code that requested permissions
     * @param permissions   permissions that were requested
     * @param grantResults  results of permissions requested
     */
    @SuppressLint("LongLogTag")
    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case LOCATION_PERMISSIONS_REQUEST_CODE:
                handleLocationPermissionsResult(grantResults);
                break;
        }
    }

    /**
     * Setup location listener
     */
    @SuppressLint({"MissingPermission", "LongLogTag"})
    private void setupLocationListener() {
        // If >= APIv23 we need to check the runtime permissions
        if (!checkIfHasPermissions()) {
            requestPermissions();
            return;
        }
        Log.d("MainActivity::setupLocationListener", "Perms OK, configuring location listener");
        lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 5, new LocationListener() {

            @Override
            public void onLocationChanged(Location location) {
                Log.d("MainActivity::setupLocationListener", "Location changed");
            }

            @Override
            public void onProviderEnabled(String provider) {
                Log.d("MainActivity::setupLocationListener", "Provider enabled");
                if (provider != LocationManager.GPS_PROVIDER) return;
                Location location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                Log.d("MainActivity::setupLocationListener", "Provider enabled, location:" + location);
            }

            @Override
            public void onProviderDisabled(String provider) {
                Log.d("MainActivity::setupLocationListener", "Provider disabled");
            }
        });
    }
}