Could not find method error when setting onClick function?

Question

 <RelativeLayout
        android:id="@+id/btn_login"
        android:layout_width="300dp"
        android:layout_height="50dp"
        android:layout_below="@id/password_bar"
        android:layout_centerInParent="true"
        android:layout_marginTop="70dp"
        android:background="@drawable/login_signup_btn_bg"
        android:clickable="true"
        android:onClick="login">

        <TextView
            android:id="@+id/tx_btn_login"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:fontFamily="@font/poppins_regular"
            android:onClick="login"
            android:text="Log In"
            android:textColor="@color/white"
            android:textSize="20sp" />
    </RelativeLayout>

package com.jamdev.handmedown;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.EditText;
import android.widget.Toast;


import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONObject;


import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.ArrayList;

public class LoginActivity extends AppCompatActivity {

    private String URL = "http://10.0.2.2/HandMeDown/user_login.php";
    public String username;
    public String password;
    public EditText usernameInput;
    public EditText passwordInput;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // These 3 lines hide the title and action bar
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
        getSupportActionBar().hide();
        setContentView(R.layout.activity_login);
        usernameInput = (EditText) findViewById(R.id.username_input);
        passwordInput = (EditText) findViewById(R.id.password_input);


    }
            public void login(View view){
            userAuthenticationAPI user_authentication_api = new userAuthenticationAPI();
            user_authentication_api.execute();
        }

      class userAuthenticationAPI extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... params) {

            HttpClient http_client = new DefaultHttpClient();
            HttpPost http_post = new HttpPost(URL);

            username = usernameInput.getText().toString();
            password = passwordInput.getText().toString();

            BasicNameValuePair usernameParam = new BasicNameValuePair("Username", username);
            BasicNameValuePair passwordParam = new BasicNameValuePair("Password", password);

            ArrayList<NameValuePair> name_value_pair_list = new ArrayList<>();
            name_value_pair_list.add(usernameParam);
            name_value_pair_list.add(passwordParam);

            try {
                // Send the list of name value pairs using an encoded form entity
                UrlEncodedFormEntity entity = new UrlEncodedFormEntity(name_value_pair_list);

                // Set the post object to contain the entity
                http_post.setEntity(entity);

                // Reads API response and string
                HttpResponse http_response = http_client.execute(http_post);
                InputStream input_stream = http_response.getEntity().getContent();
                InputStreamReader input_stream_reader = new InputStreamReader(input_stream);
                BufferedReader buffered_reader = new BufferedReader(input_stream_reader);
                StringBuilder string_builder = new StringBuilder();
                String buffered_str_chunk = null;
                while ((buffered_str_chunk = buffered_reader.readLine()) != null) {
                    string_builder.append(buffered_str_chunk);
                }
                Log.i("result", string_builder.toString());
                return string_builder.toString();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            try {
                JSONObject json = new JSONObject(s);
                // Returned status from the post API
                String status = json.getString("status");

                if (status.equalsIgnoreCase("accepted")) {
                    String fullName = json.getString("Name");
                    String phoneNumber = json.getString("PhoneNumber");
                    String address = json.getString("Address");
                    String username = json.getString("Username");
                    String email = json.getString("Email");
                    int profilePicture = R.drawable.profile_pic;

                    User user = new User(fullName,phoneNumber,address,username,email,profilePicture);

                    Intent intent = new Intent(LoginActivity.this, MainActivity.class);
                    intent.putExtra("User", user);
                    startActivity(intent);
                } else {
                    // If the status != accepted, the user is notified that something wrong happened
                    Toast.makeText(LoginActivity.this, status, Toast.LENGTH_SHORT).show();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

        
    }



}

The app is crashing whenever I click on the log in button. I tried removing the content inside, and just trying to make a Toast and display whatever message is inside, not budging, so it can't be from the api execute function call. I'm getting this error:

java.lang.IllegalStateException: Could not find method login(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.widget.RelativeLayout with id 'btn_login'

It's driving me nuts. I made sure it's within its scope, and when selecting the onClick function it gives me the login function as an option.