MainActivity.java

package com.example.takessharperfence;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private static final String KEY_EMAIL = "Email";
    private static final String KEY_PASSWORD = "Password";
    private static final String MyPREFERENCES = "MyPREFERENCES";

    TextView etEmail, etPassword;
    Button btnLogin;
    CheckBox cbRememberMe;


    SharedPreferences sharedpreferences;
    SharedPreferences.Editor editor;


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


        sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);
        editor = sharedpreferences.edit();

        etEmail = findViewById(R.id.et_email);
        etPassword = findViewById(R.id.et_password);

        btnLogin = findViewById(R.id.btn_login);

        cbRememberMe = findViewById(R.id.cb_remember_me);



        getCredentials();

        btnLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String email = etEmail.getText().toString();
                String password = etPassword.getText().toString();
                if (TextUtils.isEmpty(email) || TextUtils.isEmpty(password)) {
                    Toast.makeText(MainActivity.this, "Please enter email address and password!" , Toast.LENGTH_LONG).show();
                } else {
                    Toast.makeText(MainActivity.this, "You are successfully login!", Toast.LENGTH_LONG).show();
                    saveDataIfNeeded(email, password);
                }
            }
        });

    }

    private void getCredentials() {
        String email = sharedpreferences.getString(KEY_EMAIL, "") ;
        String password = sharedpreferences.getString(KEY_PASSWORD, "");

        etEmail.setText(email);
        etPassword.setText(password);

          if (!email.isEmpty() || !password.isEmpty()){
            cbRememberMe.setChecked(true);

        }

    }


    public void saveDataIfNeeded(String email, String password) {
        if (cbRememberMe.isChecked()) {

            editor.putString(KEY_EMAIL, email);
            editor.putString(KEY_PASSWORD, password);
            editor.commit();
        }
        if (!cbRememberMe.isChecked()){
            editor.clear();
            editor.apply();

        }
    }
}