Requesting Runtime Permissions

I am learning about how to request runtime permissions.
After browsing several websites, I found a simple code

After implemented above tutorial, App works fine but it is not redirecting user to app settings when required.

Code Class is

import android.Manifest;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.Handler;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MainActivity extends AppCompatActivity {

    public static final int REQUEST_ID_MULTIPLE_PERMISSIONS = 1;
    private static int SPLASH_TIME_OUT = 2000;
    private String TAG = "tag";

    @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.
            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    // This method will be executed once the timer is over
                    // Start your app main activity

                    Intent i = new Intent(MainActivity.this, WelcomeActivity.class);
                    startActivity(i);

                    // close this activity
                    finish();
                }
            }, SPLASH_TIME_OUT);
        }
    }

    private  boolean checkAndRequestPermissions() {
        int camerapermission = ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA);
        int writepermission = ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE);
        int permissionLocation = ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION);
        int permissionRecordAudio = ContextCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO);


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

        if (camerapermission != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.CAMERA);
        }
        if (writepermission != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.WRITE_EXTERNAL_STORAGE);
        }
        if (permissionLocation != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.ACCESS_FINE_LOCATION);
        }
        if (permissionRecordAudio != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.RECORD_AUDIO);
        }
        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.CAMERA, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.WRITE_EXTERNAL_STORAGE, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.ACCESS_FINE_LOCATION, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.RECORD_AUDIO, 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.CAMERA) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED 
&& perms.get(Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED 
&& perms.get(Manifest.permission.RECORD_AUDIO) == PackageManager.PERMISSION_GRANTED) {
                        Log.d(TAG, "sms & location services permission granted");
                        // process the normal flow
                        Intent i = new Intent(MainActivity.this, WelcomeActivity.class);
                        startActivity(i);
                        finish();
                        //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.CAMERA) 
|| ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) 
|| ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_FINE_LOCATION)
 || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.RECORD_AUDIO)) {
                            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.
                                                    finish();
                                                    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.exampledemo.parsaniahardik.marshmallowpermission")));
                    }
                })
                .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface paramDialogInterface, int paramInt) {
                        finish();
                    }
                });
        dialog.show();
    }
}

Can any one help me where am I doing wrong?