リソースを取得する際の処理速度について調査

MainActivity.kt

package com.github.m4kvn.resource.resourceaccesstest

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.core.view.updatePadding
import kotlinx.android.synthetic.main.activity_main.*
import java.util.concurrent.atomic.AtomicLong
import java.util.concurrent.atomic.AtomicReference

class MainActivity : AppCompatActivity() {
    private val texts = mutableListOf("各実行回数: $COUNT")
    private val startTime = AtomicLong()
    private val endTime = AtomicLong()

    private val argumentText = AtomicReference<String?>()
    private val text by lazy {
        getString(R.string.app_name)
    }
    private val x1 by lazy {
        resources.getDimensionPixelOffset(R.dimen.x1)
    }
    private val icon by lazy {
        resources.getDrawable(R.drawable.ic_launcher_foreground, null)
    }

    private fun start(title: String, action: (Int) -> Unit) {
        startTime.set(System.nanoTime())
        repeat(COUNT, action)
        endTime.set(System.nanoTime())
        val time = (endTime.get() - startTime.get()) / 1000000
        texts.add("$title\n経過時間 $time(ms)")
    }

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

        start("毎回引数ありgetString") { index ->
            textView.text = getString(R.string.argument_text, index)
        }

        start("キャッシュされた引数ありgetString") { index ->
            textView.text = argumentText.get()
                ?: getString(R.string.argument_text, index).also {
                    argumentText.set(it)
                }
        }

        start("毎回getString") {
            textView.text = getString(R.string.app_name)
        }

        start("キャッシュされたgetString") {
            textView.text = text
        }

        start("毎回resources.getDimensionPixel") {
            textView.updatePadding(left = resources.getDimensionPixelOffset(R.dimen.x1))
        }

        start("キャッシュされたresources.getDimensionPixel") {
            textView.updatePadding(left = x1)
        }

        start("毎回resources.getDrawable") {
            textView.setCompoundDrawables(
                resources.getDrawable(R.drawable.ic_launcher_foreground, null),
                null,
                null,
                null
            )
        }

        start("キャッシュされたresources.getDrawable") {
            textView.setCompoundDrawables(icon, null, null, null)
        }

        textView.text = texts.joinToString(separator = "\n\n")
    }

    companion object {
        private const val COUNT = 100000
    }
}