WP

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

Alternatif.kt

data class Alternatif(var kode: String, var nama: String) : Comparable<Alternatif> {
    var nilai = 0.0

    override fun toString(): String {
        return String.format("%s-%s:%.3f", kode, nama, nilai)
    }

    override fun compareTo(a: Alternatif): Int {
        return java.lang.Double.compare(this.nilai, a.nilai)
    }
}

Bobot.kt

const val SANGAT_TIDAK_PENTING = 1.0
const val TIDAK_PENTING = 2.0
const val CUKUP_PENTING = 3.0
const val PENTING = 4.0
const val SANGAT_PENTING = 5.0

Kriteria.kt

data class Kriteria(
    var kode: String,
    var nama: String,
    var benefit: Boolean,
    var bobot: Double
) {
    fun weighted(total: Double): Double {
        val w = bobot / total
        return if (benefit) w else w * -1
    }
}

KriteriaAlternatif.kt

data class KriteriaAlternatif(
    var alternatifKode: String,
    var kriteriaKode: String,
    var nilai: Double
) {
    var temp: Double = 0.toDouble()
}

MainActivity.kt

class MainActivity : AppCompatActivity() {
    private lateinit var alternatif: MutableList<Alternatif>
    private lateinit var kriteria: MutableList<Kriteria>
    private lateinit var kriteriaAlternatif: MutableList<KriteriaAlternatif>
    var s = ""

    @RequiresApi(Build.VERSION_CODES.N)
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        initList()
        val hasil = hitung()
        val highest = Collections.max(hasil).kode
        hasil.forEach {
            s += if (it.kode.equals(highest))
                "${it.nama} adalah yang tertinggi \n"
            else "${it.nama}\n"

        }
        text.text = s
    }

    private fun initList() {
        alternatif = mutableListOf()
        kriteria = mutableListOf()
        kriteriaAlternatif = mutableListOf()

        alternatif = Arrays.asList(
            Alternatif("A1", "Samsung Galaxy J5"),
            Alternatif("A2", "Xiaomi Redmi 4X"),
            Alternatif("A3", "Oppo A57")
        )

        kriteria = Arrays.asList(
            Kriteria("C1", "Harga", false, CUKUP_PENTING),
            Kriteria("C2", "Kapasitas RAM/ROM", true, SANGAT_PENTING),
            Kriteria("C3", "Kualitas Kamera", true, CUKUP_PENTING),
            Kriteria("C4", "Kapasitas Baterai", true, PENTING)
        )

        kriteriaAlternatif = Arrays.asList(
            KriteriaAlternatif("A1", "C1", 82.0),
            KriteriaAlternatif("A1", "C2", 76.0),
            KriteriaAlternatif("A1", "C3", 85.0),
            KriteriaAlternatif("A1", "C4", 76.0),

            KriteriaAlternatif("A2", "C1", 75.0),
            KriteriaAlternatif("A2", "C2", 80.0),
            KriteriaAlternatif("A2", "C3", 75.0),
            KriteriaAlternatif("A2", "C4", 82.0),

            KriteriaAlternatif("A3", "C1", 80.0),
            KriteriaAlternatif("A3", "C2", 76.0),
            KriteriaAlternatif("A3", "C3", 79.0),
            KriteriaAlternatif("A3", "C4", 75.0)
        )
    }

    @RequiresApi(Build.VERSION_CODES.N)
    fun pangkatW(ka: KriteriaAlternatif): KriteriaAlternatif {
        // Total nilai bobot untuk perhitungan perbaikan bobot (∑Wj)
        val totalW = kriteria.stream()
            .mapToDouble { (_, _, _, bobot) -> bobot }
            .sum()

        // Perhitungan nilai kriteria berpangkat bobot perbaikan
        kriteria.stream()
            .filter { (kode) -> ka.kriteriaKode == kode }
            .forEach { k -> ka.temp = Math.pow(ka.nilai, k.weighted(totalW)) }

        return ka
    }

    @RequiresApi(Build.VERSION_CODES.N)
    fun vecktorS(a: Alternatif): Alternatif {
        // Perhitungan nilai vektor S
        kriteriaAlternatif.stream()
            .map { pangkatW(it) }
            .filter { (alternatifKode) -> a.kode == alternatifKode }
            .forEach { ka -> a.nilai = if (a.nilai == 0.0) ka.temp else a.nilai * ka.temp }
        return a
    }

    @RequiresApi(Build.VERSION_CODES.N)
    fun hitung(): List<Alternatif> {
        // Total niali S (∑Sj)
        val totalS = alternatif.stream()
            .map { vecktorS(it) }
            .mapToDouble { a -> a.nilai }
            .sum()

        // Nilai V (Sj / ∑Sj)
        alternatif.forEach { a -> a.nilai = a.nilai / totalS }
        return alternatif
    }

}