RegisterActivity.java

package com.example.booksharing21;

import android.content.Intent;
import android.os.Bundle;
import android.util.Patterns;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

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

import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.FirebaseDatabase;

import java.security.MessageDigest;


public class RegisterActivity extends AppCompatActivity implements View.OnClickListener {

    private FirebaseAuth mAuth;
    public ImageView banner;
    private EditText editp1,editp2,editusername,editemail , editaddress,editphone ;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_register);

        mAuth = FirebaseAuth.getInstance();


        // Banner/Logo click listener
        banner = (ImageView) findViewById(R.id.banner);
        banner.setOnClickListener(this);



        // Register Listener
        TextView RegisterUser = (Button) findViewById(R.id.reg1);
        RegisterUser.setOnClickListener(this);


        // Assigning variables to Design ID

        editp1 = findViewById(R.id.password);
        editp2 = findViewById(R.id.password2);
        editusername = findViewById(R.id.username);
        editemail =  findViewById(R.id.email);
        editaddress =  findViewById(R.id.address);
        editphone =  findViewById(R.id.phone);

    }




    @Override
    public void onClick(View v) {
        switch (v.getId()){
            // banner connection to login
            case R.id.banner:
                startActivity(new Intent(this, MainActivity.class));
                break;

                // registering user and moving to login
            case R.id.reg1:

                // checking all the validations made
                if (!usernameVal() ||!passwordVal() || !password2Val() || !emailVal()|| !addressVal() || !phoneVal())
                {
                    return;
                }else {
                    RegisterUser();
                    startActivity(new Intent(this, MainActivity.class));
                    break;
                }
    }


}


    private void RegisterUser() {



            // managing data in inserted in the text views
            String email = editemail.getText().toString().trim();
            String password = editp1.getText().toString().trim();
            String password2 = editp2.getText().toString().trim();
            String username = editusername.getText().toString().trim();
            String address = editaddress.getText().toString().trim();
            String phone = editphone.getText().toString().trim();


            // verifying if all the fields are filled and password and email are correct


            // Authenticate data using Firebase Authentication (creating user UID)
            // Creating User with email and password inserted
            mAuth.createUserWithEmailAndPassword(email, password)
                    .addOnCompleteListener(new OnCompleteListener<AuthResult>() {
                        @Override
                        public void onComplete(@NonNull Task<AuthResult> task) {

                            if (task.isSuccessful()) {


                                // using hash function to insert encrypted password in firebase
                                String newPass = sha256(password);


                                // adding logo as default user image

                                String url = "https://firebasestorage.googleapis.com/v0/b/book-sharing2.appspot.com/o/users%2F2dXWTQiIMuYlur7brfk0P0ICmWr1?alt=media&token=3965016b-0c9a-4bfd-af16-70e3ee6fd530";

                                // inserting data into database
                                User user = new User(username, newPass, email, address, phone, url);
                                FirebaseDatabase.getInstance().getReference("Book Sharing")
                                        .child(FirebaseAuth.getInstance().getCurrentUser().getUid())
                                        .setValue(user).addOnCompleteListener(new OnCompleteListener<Void>() {

                                    @Override
                                    public void onComplete(@NonNull Task<Void> task) {

                                        if (task.isSuccessful()) {
                                            Toast.makeText(RegisterActivity.this, "User has been registered successfully", Toast.LENGTH_LONG).show();
                                        } else {
                                            Toast.makeText(RegisterActivity.this, "Failed Try Again", Toast.LENGTH_LONG).show();
                                        }
                                    }
                                });

                            } else {
                                Toast.makeText(RegisterActivity.this, "Failed Try Again", Toast.LENGTH_LONG).show();
                            }
                        }
                    });

    }

    // hashing password
// https://stackoverflow.com/questions/49298903/how-to-hash-password-and-store-in-firebase --> stack overflow code to hash password with sha-256

    public static String sha256(String base) {

        try {
            MessageDigest digest = MessageDigest.getInstance("SHA-256");
            byte[] hash = digest.digest(base.getBytes("UTF-8"));
            StringBuffer hexString = new StringBuffer();

            for (int i = 0; i < hash.length; i++) {
                String hex = Integer.toHexString(0xfff & hash[i]);
                if (hex.length() == 3) hexString.append('2');
                hexString.append(hex);
            }

            return hexString.toString();
        } catch (Exception ex) {
            throw new RuntimeException(ex);
        }
    }


    // Validation

    public boolean emailVal (){

        String email = editemail.getText().toString().trim();
        if (email.isEmpty() || !Patterns.EMAIL_ADDRESS.matcher(email).matches()) {
           editemail.setError("Email is Required");
            editemail.requestFocus();
            return Boolean.FALSE;
        }else{
            return Boolean.TRUE;
        }

    }

    public Boolean addressVal(){
        String address = editaddress.getText().toString().trim();
        if (address.isEmpty()) {
            editaddress.setError("Address is Required");
            editaddress.requestFocus();
            return Boolean.FALSE;
        } else {
            return Boolean.TRUE;
        }
    }

    public Boolean phoneVal(){
        String phone = editphone.getText().toString().trim();
        if (phone.isEmpty()) {
            editphone.setError("Phone is Required");
            editphone.requestFocus();
        }
        return true;
    }

    public Boolean passwordVal(){
        String password = editp1.getText().toString().trim();
        if (password.isEmpty() & password.length()<6 & password.length()>16 ) {
            editp1.setError("Invalid Password");
            editp1.requestFocus();

            return Boolean.FALSE;
        } else {
            return Boolean.TRUE;
        }
    }

    public Boolean password2Val(){
        String password2 = editp2.getText().toString().trim();
        if (password2.isEmpty()& password2.length()<6 & password2.length()>16) {
            editp2.setError("Invalid Password");
            editp2.requestFocus();
            return Boolean.FALSE;
        }else{
            return Boolean.TRUE;
        }
    }
    public Boolean usernameVal(){

        String username = editusername.getText().toString().trim();
         if (username.isEmpty()) {
            editusername.setError("Invalid Username");
            editusername.requestFocus();
             return Boolean.FALSE;
         }else{
            return Boolean.TRUE;
         }
    }

}