SignupActivity.java

package com.example.connect;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.FirebaseApp;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.firestore.FirebaseFirestore;

public class SignupActivity extends AppCompatActivity {
    FirebaseAuth auth;

    TextView email , password , name;
    Button login, signup;
    FirebaseFirestore database;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_signup);
        database = FirebaseFirestore.getInstance();
        auth = FirebaseAuth.getInstance();

        email = findViewById(R.id.email);
        password = findViewById(R.id.password);
        login = findViewById(R.id.button);
        signup = findViewById(R.id.button2);
        name = findViewById(R.id.Name);

        signup.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String Email,Password,Name;
                Email = email.getText().toString();
                Password = password.getText().toString();
                Name = name.getText().toString();

                User user = new User();

                user.setEmail(Email);
                user.setName(Name);
                user.setPassword(Password);

                auth.createUserWithEmailAndPassword(Email,Password).addOnCompleteListener(new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        if(task.isSuccessful()){
                            database.collection("Users").document().set(user).addOnSuccessListener(new OnSuccessListener<Void>() {
                                @Override
                                public void onSuccess(Void aVoid) {
                                    startActivity(new Intent(SignupActivity.this,LoginActivity.class));
                                }
                            });
                            Toast.makeText(SignupActivity.this, "Account is Created", Toast.LENGTH_SHORT).show();
                        }
                        else{
                            Toast.makeText(SignupActivity.this,task.getException().getLocalizedMessage(), Toast.LENGTH_SHORT).show();
                        }
                    }
                });
            }
        });
    }
}