2020 Jul. 19.
参考元 https://qiita.com/ntsk/items/6eafe7bd7edbab61341e
// MainActivity.kt override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) if (savedInstanceState != null) { myVarBool = savedInstanceState.getBoolean("myBool") } } // onSaveInstanceStateはonPauseの直後に呼ばれる override fun onSaveInstanceState(outState: Bundle) { super.onSaveInstanceState(outState) outState.putBoolean("myBool", myVarBool) }