Öncelikle strings.xml dosyasını oluşturalım.

<resources>
    <string name="app_name">Kullanıcı Adı ve Şifre</string>
    <string name="test_username">atml</string>
    <string name="test_password">1234</string>
    <string name="caption">Kullanıcı Girişi</string>
    <string name="login_error">Kullanıcı Adı veya Şifre Hatalı</string>
</resources>

Şimdi login.xml dosyasını oluşturalım.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="50dp"
        android:text="@string/caption"
        android:textSize="30sp"
        android:textStyle="bold|italic" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="30dp"
        android:layout_marginTop="30dp"
        android:orientation="horizontal">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Kullanıcı Adı : "
            android:textSize="18sp" />

        <EditText
            android:id="@+id/etUserName"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            android:ems="10" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="30dp"
        android:orientation="horizontal">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Şifre : "
            android:textSize="18sp" />

        <EditText
            android:id="@+id/etPassword"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="70dp"
            android:ems="10" />
    </LinearLayout>

    <CheckBox
        android:id="@+id/chkRememberMe"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="30dp"
        android:text="Beni Hatırla" />

    <Button
        android:id="@+id/btnLogin"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:text="Giriş" />

</LinearLayout>

Şimdi LoginActivity.java dosyasını oluşturalım.

package com.example.remembermelogin;

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

import androidx.appcompat.app.AppCompatActivity;

import org.jetbrains.annotations.Nullable;

public class LoginActivity extends AppCompatActivity {
    EditText etUserName, etPassword;
    CheckBox chkRememberMe;
    Button btnLogin;
    ShredPreferenc shredPreferenc;
    Context context = this;

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

        init();

        if (shredPreferenc.getValueBoolean(context, "remember")) {
            etUserName.setText(shredPreferenc.getValue(context, "username"));
            chkRememberMe.setChecked(shredPreferenc.getValueBoolean(context, "remember"));
        }

        btnLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (etUserName.getText().toString().equals(getText(R.string.test_username)) &&
                        etPassword.getText().toString().equals(getText(R.string.test_password))) {
                    Intent intent = new Intent(context, MainActivity.class);
                    startActivity(intent);

                    if (chkRememberMe.isChecked()) {
                        shredPreferenc.save(context, "username", etUserName.getText().toString());
                    } else {
                        shredPreferenc.save(context, "username", "");
                    }

                    shredPreferenc.saveBoolean(context, "remember", chkRememberMe.isChecked());

                } else {
                    Toast.makeText(context, getString(R.string.login_error), Toast.LENGTH_SHORT).show();
                }
            }
        });
    }

    public void init() {
        etUserName = findViewById(R.id.etUserName);
        etPassword = findViewById(R.id.etPassword);
        chkRememberMe = findViewById(R.id.chkRememberMe);
        btnLogin = findViewById(R.id.btnLogin);
        shredPreferenc = new ShredPreferenc();
    }
}

Sıra geldi activity_main.xml dosyasını oluşturmaya.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:id="@+id/txtHosgeldin"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="" />

</LinearLayout>

Şimdi MainActivity.java dosyasını oluşturalım.

package com.example.remembermelogin;

import android.annotation.SuppressLint;
import android.content.Context;
import android.os.Bundle;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {
    ShredPreferenc shredPreferenc;
    Context context = this;
    TextView txtHosgeldin;

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

        txtHosgeldin = findViewById(R.id.txtHosgeldin);
        shredPreferenc = new ShredPreferenc();

        txtHosgeldin.setText(shredPreferenc.getValue(context, "username"));
    }
}

Son olarak ShredPreferenc.java sınıfını oluşturalım.

package com.example.remembermelogin;

import android.content.Context;
import android.content.SharedPreferences;

public class ShredPreferenc {
    static final String PREF_NAME = "Login";

    public void save(Context context, String key, String value) {
        SharedPreferences settings = context.getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = settings.edit();
        editor.putString(key, value);
        editor.commit();
    }

    public void saveBoolean(Context context, String key, Boolean value) {
        SharedPreferences settings = context.getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = settings.edit();
        editor.putBoolean(key, value);
        editor.commit();
    }

    public String getValue(Context context, String key) {
        SharedPreferences settings = context.getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE);
        String text = settings.getString(key, null);
        return text;
    }

    public Boolean getValueBoolean(Context context, String key) {
        SharedPreferences settings = context.getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE);
        Boolean text = settings.getBoolean(key, false);
        return text;
    }
    public void clear(Context context) {
        SharedPreferences settings = context.getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = settings.edit();
        editor.clear();
        editor.commit();
    }

    public void remove(Context context, String key) {
        SharedPreferences settings = context.getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = settings.edit();
        editor.remove(key);
        editor.commit();
    }

}

Şimdi de projeye ait ayarlamaların ve izinlerin yapıldığı manifest dosyasına aşağıdaki satırları ekleyelim.

        <activity android:name=".LoginActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".MainActivity"></activity>

Projeyi çalıştıralım. Gerekli bilgileri girdiğimizde ikinci sayfanın ekrana geldiğini görürsünüz.