In order to login, you must have created a database and a table. Hence, it is advised that you first execute the Registration Form program because here we will be using the UserLoginTable, and DatabaseConfig.php created in the Registration Form program.
Create login.php file inside public_html folder and write the following code.
<?php
include 'DatabaseConfig.php';
$email = isset($_POST['email']) ? $_POST["email"] : '';;
$password = isset($_POST['password']) ? $_POST["password"] : '';;
$Sql_Query = "select * from UserLoginTable where email = '$email' and password = '$password' ";
$check = mysqli_fetch_array(mysqli_query($con,$Sql_Query));
if(isset($check))
{
echo "Success";
}
else
{
echo "Invalid Username or Password Please Try Again";
}
mysqli_close($con);
?>
Step 1: Start an android project.
Step 2: Design the first page as shown in the figure.

Step 3: Open the AndroidManifest.xml file and add the following line after the application tag.
<uses-permission android:name="android.permission.INTERNET" />
Step 4: Open build.gradle(Module:………..) file, inside dependencies, add the following code and synchronize the project.
implementation 'com.android.volley:volley:1.1.1
Step 5: Create a second page and design it with one textview to display a message “Login Successful”.
Step 6: Open MainActivity.java and add the following code.
package com.example.part_b6_login_demo;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.RequestQueue;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.Volley;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.HashMap;
import java.util.Map;
public class MainActivity extends AppCompatActivity {
// 1. Add <uses-permission android:name="android.permission.INTERNET" /> in
// AndroidManifest.xml just before <application tag
// 2. Add implementation 'com.android.volley:volley:1.2.1' in build.gradle (:app)
//3. Add php file to web server
EditText Email,Password;
TextView login_fail;
Button login;
String PasswordHolder, EmailHolder;
String webhost_path="YOUR_WEBSITE_URL/login.php";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Assign Id'S
Email = (EditText) findViewById(R.id.txt_email);
Password = (EditText) findViewById(R.id.txt_password);
login = (Button) findViewById(R.id.btn_login);
TextView text=(TextView)findViewById(R.id.textView2);
login_fail=(TextView)findViewById(R.id.txt_login_fail);
login.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
EmailHolder = Email.getText().toString();
PasswordHolder = Password.getText().toString();
login_User(EmailHolder,PasswordHolder);
}
});
}
public void login_User(String EmailHolder, String PasswordHolder)
{
final StringRequest stringRequest1=new StringRequest(Request.Method.POST, webhost_path, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
try{
if(response.equals("Success"))
{
login_fail.setText("");
Toast.makeText(getApplicationContext(),"Login Successful", Toast.LENGTH_LONG).show();
Intent in=new Intent(MainActivity.this, Second_Page.class);
startActivity(in);
}else{
login_fail.setText("Login failed, check user name and password");
Toast.makeText(getApplicationContext(), response, Toast.LENGTH_SHORT).show();
}
}catch (Exception e){
Toast.makeText(getApplicationContext(), "Exception occurred", Toast.LENGTH_SHORT).show();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(), "Login error", Toast.LENGTH_SHORT).show();
}
})
{
protected Map<String,String> getParams() {
Map<String, String> params = new HashMap<>();
params.put("email", EmailHolder);
params.put("password", PasswordHolder);
return params;
}
};
final RequestQueue requestQueue1 = Volley.newRequestQueue(MainActivity.this);
requestQueue1.add(stringRequest1);
}
}
Step 7: Run the project.