Login

package com.example.ronel.finalapp;

import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

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.auth.FirebaseUser;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;

public class Login extends AppCompatActivity {

    EditText etMail, etPass;
    Button btn;
    String mail,pass;
    Intent go;
    private FirebaseAuth mAuth;
    DatabaseReference ref;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        etMail = findViewById(R.id.etMail);
        etPass = findViewById(R.id.etPass);
        btn = findViewById(R.id.btn);

        mAuth = FirebaseAuth.getInstance();
    }

    public void func(View view) {
        mail = etMail.getText().toString();
        pass = etPass.getText().toString();
        if (TextUtils.isEmpty(mail)) {
            Toast.makeText(this, "Enter mail", Toast.LENGTH_SHORT).show();
            return;
        }
        if (TextUtils.isEmpty(pass)) {
            Toast.makeText(this, "Enter password", Toast.LENGTH_SHORT).show();
            return;
        }
        //If it's regular user:
        if (!mail.equals("[email protected]")) {

            //Sign-in
            mAuth.signInWithEmailAndPassword(mail, pass)
                    .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                        @Override
                        public void onComplete(@NonNull Task<AuthResult> task) {
                            if (task.isSuccessful()) {
                                // Sign in success, update UI with the signed-in user's information
                                Log.d("good", "signInWithEmail:success");
                                FirebaseUser user = mAuth.getCurrentUser();
                                Toast.makeText(Login.this, "Sign in success",
                                        Toast.LENGTH_SHORT).show();
                            } else {
                                // If sign in fails, display a message to the user.
                                Log.w("bad", "signInWithEmail:failure", task.getException());
                                Toast.makeText(Login.this, "Authentication failed.",
                                        Toast.LENGTH_SHORT).show();
                            }

                            // ...
                        }
                    });
        }
        //If manager
        else {
            ref = FirebaseDatabase.getInstance().getReference().child("manager");
            final String[] s = new String[1];
            ref.addListenerForSingleValueEvent(
                    new ValueEventListener() {
                        @Override
                        public void onDataChange(DataSnapshot dataSnapshot) {

                            //Get map of users in datasnapshot

                            s[0] = dataSnapshot.getValue(String.class);
                            Log.d("Admin password", s[0]);
                            //Check if password is the same as typed:
                            if (pass.equals(s[0])) {
                                continueList();
                            }
                            else {
                                Toast.makeText(Login.this,"Change your email",Toast.LENGTH_SHORT);
                                return;
                            }
                        }

                        @Override
                        public void onCancelled(DatabaseError databaseError) {
                            //handle databaseError
                        }
                    });
        }
    }
    //Send manager to "manager view page"
    private void continueList() {
        Toast.makeText(Login.this,"Admin registered",Toast.LENGTH_SHORT);
        go = new Intent(this, AdminPageView.class);
        startActivity(go);
    }
}