ネストしたデータをresourceで管理する ref: https://qiita.com/bassaer/items/b1d3f9bacb03033e3a46

arrays.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <array name="menu">
        <item>@array/food_menu</item>
        <item>@array/drink_menu</item>
    </array>

    <array name="food_menu">
        <item>food</item>
        <item>@array/food_array</item>
    </array>

    <array name="drink_menu">
        <item>drink</item>
        <item>@array/drink_array</item>
    </array>

    <string-array name="food_array">
        <item>Sandwich</item>
        <item>Hot dog</item>
        <item>Salad</item>
        <item>Donuts</item>
    </string-array>

    <string-array name="drink_array">
        <item>Coffee</item>
        <item>Tea</item>
        <item>Coke</item>
        <item>Water</item>
    </string-array>
</resources>

file0.txt

{
  "menu": {
    "food": [
      "Samdwich",
      "Hot dog",
      "Salad",
      "Donuts"
    ],
    "drink": [
      "Coffee",
      "Tea",
      "Coke",
      "Water"
    ]
  }
}

file3.txt

05-19 05:44:01.973 5423-5423/com.github.bassaer.nestarrayapp D/Sample: food
05-19 05:44:01.973 5423-5423/com.github.bassaer.nestarrayapp D/Sample:  └── Sandwich
05-19 05:44:01.973 5423-5423/com.github.bassaer.nestarrayapp D/Sample:  └── Hot dog
05-19 05:44:01.973 5423-5423/com.github.bassaer.nestarrayapp D/Sample:  └── Salad
05-19 05:44:01.973 5423-5423/com.github.bassaer.nestarrayapp D/Sample:  └── Donuts
05-19 05:44:01.974 5423-5423/com.github.bassaer.nestarrayapp D/Sample: drink
05-19 05:44:01.974 5423-5423/com.github.bassaer.nestarrayapp D/Sample:  └── Coffee
05-19 05:44:01.974 5423-5423/com.github.bassaer.nestarrayapp D/Sample:  └── Tea
05-19 05:44:01.974 5423-5423/com.github.bassaer.nestarrayapp D/Sample:  └── Coke
05-19 05:44:01.974 5423-5423/com.github.bassaer.nestarrayapp D/Sample:  └── Water

MainActivity.kt

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        loadMenu()
    }

    private fun loadMenu() {
        val tag = "Sample"
        // <array name="menu">のデータを読み込む
        val menus = resources.obtainTypedArray(R.array.menu)

        // 0番目がメニューの名前で、1番目がメニュー配列のResourceID
        @StyleableRes val nameIndex = 0
        @StyleableRes val arrayIndex = 1

        for (i in 0 until menus.length()) {
            // @array/*_menu のResourceIdを取得
            val menuId = menus.getResourceId(i, -1)
            if (menuId < 0) {
                break
            }
            // @array/*_arrayを読み込む
            val menu = resources.obtainTypedArray(menuId)

            // 1番目のメニュー配列のResourceIDを取得
            val arrayId = menu.getResourceId(arrayIndex, -1)
            if (arrayId < 0) {
                menu.recycle()
                break
            }
            // メニュー配列取得
            val array = resources.obtainTypedArray(arrayId)

            // 出力
            Log.d(tag, menu.getString(nameIndex))
            for (j in 0 until array.length()) {
                Log.d(tag, " └── " + array.getString(j))
            }

            menu.recycle()
            array.recycle()
        }
        menus.recycle()
    }
}