Check Internet Connection in Android Exmaple

public static boolean checkMobileInternetConn(Context _context) {
   //Create object for ConnectivityManager class which returns network related info 

 ConnectivityManager connectivity = (ConnectivityManager) _context
         .getSystemService(Context.CONNECTIVITY_SERVICE);
   //If connectivity object is not null   if (connectivity != null) {
      //Get network info - WIFI internet access 

 NetworkInfo info = connectivity.getNetworkInfo(ConnectivityManager.TYPE_WIFI) ;
       NetworkInfo info1= connectivity.getNetworkInfo(ConnectivityManager.TYPE_MOBILE) ;

      if (info != null || info1!=null) {
         //Look for whether device is currently connected to WIFI network 

 if (info.isConnected() || info1.isConnected()) {
            return true;
         }
      }
   }
   return false;
}

Set the time otp generate in Android Example

//set on time 132 second and resend 

public void reverseTimer(int Seconds,final TextView tv){

    new CountDownTimer(Seconds* 1000+1000, 1000) {

        public void onTick(long millisUntilFinished) {
            int seconds = (int) (millisUntilFinished / 1000);
            int minutes = seconds / 60;
            seconds = seconds % 60;
           tv.setText("TIME : " + String.format("%02d", minutes)
                    + ":" + String.format("%02d", seconds));
        }

        public void onFinish() {
            tv.setText(getString(R.string.nototp));
            tv.setOnClickListener(new View.OnClickListener() {
                @Override                public void onClick(View v) {
                    reverseTimer(90,tv);
                    // new OTPDATA().execute();                }
            });
        }
    }.start();
}

Activity Lifecycle in Android

Give the Run time Permission in Marshmallow on Android

  private  boolean checkAndRequestPermissions() {
        int phoneread = ContextCompat.checkSelfPermission(this,
                Manifest.permission.READ_PHONE_STATE);
        int READ_CONTACTS = ContextCompat.checkSelfPermission(this, Manifest.permission.READ_CONTACTS);
        int ACCESS_FINE_LOCATION = ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION);
        int WRITE_CONTACTS = ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_CONTACTS);
        int READ_CALL_LOG = ContextCompat.checkSelfPermission(this, Manifest.permission.READ_CALL_LOG);
        int WRITE_CALL_LOG = ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_CALL_LOG);
        int CALL_PHONE = ContextCompat.checkSelfPermission(this, Manifest.permission.CALL_PHONE);
        int READ_EXTERNAL_STORAGE = ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE);
        int KILLPROCESS = ContextCompat.checkSelfPermission(this, Manifest.permission.KILL_BACKGROUND_PROCESSES);
        int WRITECONTACT=ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_CONTACTS);
        int WIFI=ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_WIFI_STATE);
        int CWIFI=ContextCompat.checkSelfPermission(this, Manifest.permission.CHANGE_WIFI_STATE);
        int ACCESS = ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION);
        int ACCESSFINE=ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION);

        List<String> listPermissionsNeeded = new ArrayList<>();
        if (READ_CONTACTS != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.READ_CONTACTS);
        }
        if (phoneread != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.READ_PHONE_STATE);
        }
        if (ACCESS_FINE_LOCATION != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.ACCESS_FINE_LOCATION);
        }  if (WRITE_CONTACTS != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.WRITE_CONTACTS);
        }  if (READ_CALL_LOG != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.READ_CALL_LOG);
        }  if (WRITE_CALL_LOG != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.WRITE_CALL_LOG);
        }
        if (CALL_PHONE != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.CALL_PHONE);
        } if (READ_EXTERNAL_STORAGE != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.READ_EXTERNAL_STORAGE);
        }
        if (KILLPROCESS != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.KILL_BACKGROUND_PROCESSES);
        }
        if (WRITECONTACT != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.WRITE_CONTACTS);
        }
        if (WIFI != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.ACCESS_WIFI_STATE);
        }
        if (CWIFI != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.CHANGE_WIFI_STATE);
        }
        if (ACCESS != PackageManager.PERMISSION_GRANTED) {
            listPermissionsNeeded.add(Manifest.permission.ACCESS_COARSE_LOCATION);
        }
        if (ACCESSFINE != 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("Permission", "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.READ_PHONE_STATE, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.READ_CONTACTS, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.ACCESS_FINE_LOCATION, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.WRITE_CONTACTS, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.READ_CALL_LOG, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.WRITE_CALL_LOG, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.CALL_PHONE, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.READ_EXTERNAL_STORAGE, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.KILL_BACKGROUND_PROCESSES, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.WRITE_CONTACTS, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.ACCESS_WIFI_STATE, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.CHANGE_WIFI_STATE, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.ACCESS_COARSE_LOCATION, PackageManager.PERMISSION_GRANTED);
                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.READ_PHONE_STATE) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.READ_CONTACTS) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.WRITE_CONTACTS) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.READ_CALL_LOG) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.WRITE_CALL_LOG) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.CALL_PHONE) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.KILL_BACKGROUND_PROCESSES) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.WRITE_CONTACTS) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.ACCESS_WIFI_STATE) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.CHANGE_WIFI_STATE) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED
                            && perms.get(Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED


                            ) {
                        Log.d("Permission", "sms & location services permission granted");
                        // process the normal flow
                        //else any one or both the permissions are not granted
                    } else {
                        Log.d("Permission", "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.READ_PHONE_STATE)
                                || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.READ_CONTACTS)
                                || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_FINE_LOCATION)
                                || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_CONTACTS)
                                || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.READ_CALL_LOG)
                                || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_CALL_LOG)
                                || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CALL_PHONE)
                                || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.READ_EXTERNAL_STORAGE)
                                || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.KILL_BACKGROUND_PROCESSES)
                                || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_CONTACTS)
                                || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_WIFI_STATE)
                                || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CHANGE_WIFI_STATE)
                                || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_COARSE_LOCATION)
                                || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_FINE_LOCATION)



                                )









                        {
                            showDialogOK("SMS and Location Services Permission 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.
                                                    break;
                                            }
                                        }
                                    });
                        }
                        //permission is denied (and never ask again is  checked)
                        //shouldShowRequestPermissionRationale will return false
                        else {

                            //                            //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();
    }