@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putBoolean("isChecked", simpleListItemChecked.isChecked());
}

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

    simpleListItemChecked = findViewById(R.id.simpleListItemChecked);

    if (savedInstanceState != null) {
        boolean isChecked = savedInstanceState.getBoolean("isChecked");
        simpleListItemChecked.setChecked(isChecked);
    }
}