How to Add Login With SMS Function in Flutter App?

1. At first we will design the UI. Where we will be adding three buttons for login with SMS, Facebook And Google.

Container(
              child: Text('Or Login With'),
            ),
            SizedBox(
              height: 10,
            ),
            Container(
              alignment: Alignment.center,
              child: Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [


                  GestureDetector(
                      onTap: () {
                        Navigator.push(
                          context,
                          MaterialPageRoute(
                              builder: (context) => const Register()),
                        );
                      },
                      child: Icon(Icons.sms),
                  ),
                  SizedBox(
                    width: 20,
                  ),
                  GestureDetector(
                    onTap: () {
                      Navigator.push(
                        context,
                        MaterialPageRoute(
                            builder: (context) => const Register()),
                      );
                    },
                    child: Icon(Icons.facebook),
                  ),
                  SizedBox(
                    width: 20,
                  ),
                  GestureDetector(
                    onTap: () {
                      Navigator.push(
                        context,
                        MaterialPageRoute(
                            builder: (context) => const Register()),
                      );
                    },
                    child: Icon(Icons.g_translate),
                  ),
                ],
              ),
            )

2. Next, we will create a screen for login with SMS called smslogin screen.

return Scaffold(
      body: SingleChildScrollView(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Container(
              margin: EdgeInsets.only(top: 100, bottom: 0),
            ),
            Image.network(
              'https://indiawebdesigns.in/assets/img/forgot.png',
              height: 300,
            ),
            Container(
                margin: EdgeInsets.only(left: 20, right: 20, top: 0, bottom: 5),
                child: Text(
                  'Login to your Account',
                  style: TextStyle(fontSize: 25),
                )),
            Container(
              margin: EdgeInsets.only(left: 20, right: 20, top: 5, bottom: 5),
              child: TextField(
                controller: phoneController,
                decoration: InputDecoration(
                  border: OutlineInputBorder(),
                  hintText: '10 Digit Mobile Number',
                  focusColor: Colors.black,
                ),
              ),
            ),

            Container(
              margin: EdgeInsets.symmetric(horizontal: 50),
              // Add left and right margin here
              child: ElevatedButton(
                onPressed: () {
                  forgotsms(context);
                },
                child: Text(
                  'Reset Password',
                  style: TextStyle(fontSize: 18, color: Colors.white),
                ),
                style: ElevatedButton.styleFrom(
                  backgroundColor: Colors.deepPurple,
                  shape: RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(10),
                  ),
                  minimumSize: Size(double.infinity, 40),
                  padding: EdgeInsets.symmetric(
                      horizontal: 20), // Add padding here if needed
                ),
              ),
            ),
            Container(
              margin: EdgeInsets.only(top: 20, bottom: 5),
              child: GestureDetector(
                  onTap: () {
                    Navigator.push(
                      context,
                      MaterialPageRoute(builder: (context) => const Login()),
                    );
                  },
                  child: Text('Back to Previous',
                      style: TextStyle(fontSize: 15))),
            ),

          ],
        ),
      ),
    );

3. Now, we will create the function for checking if the number exists in database and if yes then hit the API of SMS

final TextEditingController phoneController = TextEditingController();

  Future<void> forgotsms(BuildContext context) async {
    String getPhone = phoneController.text;


    // Make a POST request to the PHP file endpoint
    var url = Uri.parse(
        'https://indiawebdesigns.in/corporate-admin/controllers/Flutter/forgotsms.php');
    var response = await http.post(url, body: {
      'phone': getPhone
    });

    // Print the response and its body for debugging
    print('Response status: ${response.statusCode}');
    print('Response body: ${response.body}');

    // Parse the response JSON
    var data = jsonDecode(response.body);

    if (data != null && data['success'] != null && data['success']) {
      // Navigate to the dashboard screen
      Navigator.pushReplacement(
        context,
        MaterialPageRoute(
          builder: (context) => Home(),
        ),
      );
    } else {
      // Show an error message
      showDialog(
        context: context,
        builder: (BuildContext context) {
          return AlertDialog(
            title: Text('Error'),
            content: Text('Mobile Number Not Found.'),
            actions: [
              TextButton(
                onPressed: () {
                  Navigator.pop(context);
                },
                child: Text('OK'),
              ),
            ],
          );
        },
      );
    }
  }

4. We will then visit a website called mysms.webotapp.com and create an account and link it to our mobile

Once we receive the SMS API Key we will then create the script for sending SMS.

//curl

$curl = curl_init();
$message1 = "Dear $name, your otp for login is $otp. Thank you.";
$message2 = urlencode("$message1");

curl_setopt_array($curl, array(
CURLOPT_URL => "https://mysms.webotapp.com/services/send.php?key=YOUR-API-KEY&number=91$phone&message=$$message2&devices=3%7C0&type=sms&prioritize=0",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => '',
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 0,
CURLOPT_FOLLOWLOCATION => true,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => 'GET',
));
$response = curl_exec($curl);
curl_close($curl);
//echo $response;

5. Now we will create the API for SMS Login and check if the phone number exists in database.

<?php

// Enable CORS headers
header("Access-Control-Allow-Origin: *");
header("Access-Control-Allow-Methods: GET, POST");
header("Access-Control-Allow-Headers: Content-Type");


 

ob_start();
require_once('../../database.php');

// Retrieve the username and password from the POST request
$userphone = $_POST['phone'];

// Query the database to check if credentials match
$query = "SELECT * FROM users WHERE user_phone = :phone AND status = 'Active'";
$stmt = $dbconn->prepare($query);
$stmt->bindParam(':phone', $userphone);
$stmt->execute();
$user = $stmt->fetch(PDO::FETCH_ASSOC);

if ($user) {
    
    //Add the SMS API CODE HERE 
    
    //curl
        $phone = $user['user_phone'];
        $name = $user['user_name'];
        $id =  $user['id'];
        $curl = curl_init();
        $message1 = "Dear $name, your otp for login is $otp. Thank you.";
        $message2 = urlencode("$message1");
        
        curl_setopt_array($curl, array(
        CURLOPT_URL => "https://mysms.webotapp.com/services/send.php?key=d9786be3e0b77c6dab3e83479e27b1d94ee72235&number=91$phone&message=$message2&devices=3%7C0&type=sms&prioritize=0",
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_ENCODING => '',
        CURLOPT_MAXREDIRS => 10,
        CURLOPT_TIMEOUT => 0,
        CURLOPT_FOLLOWLOCATION => true,
        CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
        CURLOPT_CUSTOMREQUEST => 'GET',
        ));
        $response = curl_exec($curl);
        curl_close($curl);
        //echo $response;
        
        
    // Valid credentials
    $response = [
        'success' => true,
        'message' => 'Succesfully Validated',
        'user_phone' => $user['user_phone'],
        'user_name' => $user['user_name'],
        'id' => $user['id'],
    ];
    
    


} else {
    // Invalid credentials
    $response = [
        'success' => false,
        'message' => 'Invalid username or password',
    ];
}

// Send the response as JSON
header('Content-Type: application/json');
echo json_encode($response);

6. In the next step we will have to create a new password and store it in our database

<?php

// Enable CORS headers
header("Access-Control-Allow-Origin: *");
header("Access-Control-Allow-Methods: GET, POST");
header("Access-Control-Allow-Headers: Content-Type");


 

ob_start();
require_once('../../database.php');

// Retrieve the username and password from the POST request
$userphone = $_POST['phone'];

// Query the database to check if credentials match
$query = "SELECT * FROM users WHERE user_phone = :phone AND status = 'Active'";
$stmt = $dbconn->prepare($query);
$stmt->bindParam(':phone', $userphone);
$stmt->execute();
$user = $stmt->fetch(PDO::FETCH_ASSOC);

if ($user) {
    
    //Add the SMS API CODE HERE 
    
    //curl
        $phone = $user['user_phone'];
        $name = $user['user_name'];
        $id =  $user['id'];
        
        
        
          //Update OTP
        $otp = rand(100000,999999);
        $encrypted_password = md5($otp);
        $sql_1 = "UPDATE users SET user_password = :value1 WHERE id = :id";
        $stmt_1 = $dbconn->prepare($sql_1);
        $stmt_1->bindParam(':value1', $encrypted_password);
        $stmt_1->bindParam(':id', $id);
        $stmt_1->execute();
        
        
        
        $curl = curl_init();
        $message1 = "Dear $name, your otp for login is $otp. Thank you.";
        $message2 = urlencode("$message1");
        
        curl_setopt_array($curl, array(
        CURLOPT_URL => "https://mysms.webotapp.com/services/send.php?key=d9786be3e0b77c6dab3e83479e27b1d94ee72235&number=91$phone&message=$message2&devices=3%7C0&type=sms&prioritize=0",
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_ENCODING => '',
        CURLOPT_MAXREDIRS => 10,
        CURLOPT_TIMEOUT => 0,
        CURLOPT_FOLLOWLOCATION => true,
        CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
        CURLOPT_CUSTOMREQUEST => 'GET',
        ));
        $response = curl_exec($curl);
        curl_close($curl);
        //echo $response;
        
        
        
      
        
        
    // Valid credentials
    $response = [
        'success' => true,
        'message' => 'Succesfully Validated',
        'user_phone' => $user['user_phone'],
        'user_name' => $user['user_name'],
        'id' => $user['id'],
    ];
    
    


} else {
    // Invalid credentials
    $response = [
        'success' => false,
        'message' => 'Invalid username or password',
    ];
}

// Send the response as JSON
header('Content-Type: application/json');
echo json_encode($response);