Android Developers Japan Blog: 古い端末でも Edge-to-edge にしたい 👉 https://android-developers-jp.googleblog.com/2023/01/is-your-app-providing-a-backward-compatible-edge-to-edge-experience.html

e2e-ui.kt

package com.example.android.e2e.ui

import android.content.res.Configuration
import android.content.res.Resources
import android.os.Build
import android.view.View
import android.view.Window
import android.view.WindowManager
import androidx.annotation.RequiresApi
import androidx.core.app.ComponentActivity
import androidx.core.content.res.ResourcesCompat
import androidx.core.view.WindowCompat
import androidx.core.view.WindowInsetsControllerCompat
import com.example.android.e2e.R

/**
 * Configures edge-to-edge for the activity.
 *
 * ```
 *   override fun onCreate(savedInstanceState: Bundle?) {
 *     setUpEdgeToEdge()
 *     super.onCreate(savedInstanceState)
 *     ...
 *   }
 * ```
 */
fun ComponentActivity.setUpEdgeToEdge() {
  val impl = if (Build.VERSION.SDK_INT >= 29) {
    EdgeToEdgeApi29()
  } else if (Build.VERSION.SDK_INT >= 26) {
    EdgeToEdgeApi26()
  } else if (Build.VERSION.SDK_INT >= 23) {
    EdgeToEdgeApi23()
  } else if (Build.VERSION.SDK_INT >= 21) {
    EdgeToEdgeApi21()
  } else {
    EdgeToEdgeBase()
  }
  impl.setUp(window, findViewById(android.R.id.content), theme)
}

private fun isDarkMode(resources: Resources): Boolean {
  return (resources.configuration.uiMode and Configuration.UI_MODE_NIGHT_MASK) == Configuration.UI_MODE_NIGHT_YES
}

private interface EdgeToEdgeImpl {
  fun setUp(window: Window, view: View, theme: Resources.Theme)
}

@RequiresApi(29)
private class EdgeToEdgeApi29 : EdgeToEdgeImpl {
  override fun setUp(window: Window, view: View, theme: Resources.Theme) {
    WindowCompat.setDecorFitsSystemWindows(window, false)
    val resources = view.resources
    val transparent = ResourcesCompat.getColor(resources, android.R.color.transparent, theme)
    val isDarkMode = isDarkMode(resources)
    window.statusBarColor = transparent
    window.navigationBarColor = transparent
    val controller = WindowInsetsControllerCompat(window, view)
    controller.isAppearanceLightStatusBars = !isDarkMode
    controller.isAppearanceLightNavigationBars = !isDarkMode
  }
}

@RequiresApi(26)
private class EdgeToEdgeApi26 : EdgeToEdgeImpl {
  override fun setUp(window: Window, view: View, theme: Resources.Theme) {
    WindowCompat.setDecorFitsSystemWindows(window, false)
    val resources = view.resources
    val transparent = ResourcesCompat.getColor(resources, android.R.color.transparent, theme)
    // R.color.navigation_bar_scrim_light is #63FFFFFF for example.
    val scrim = ResourcesCompat.getColor(resources, R.color.navigation_bar_scrim_light, theme)
    window.statusBarColor = transparent
    window.navigationBarColor = scrim
    val controller = WindowInsetsControllerCompat(window, view)
    controller.isAppearanceLightStatusBars = true
    controller.isAppearanceLightNavigationBars = true
  }
}

@RequiresApi(23)
private class EdgeToEdgeApi23 : EdgeToEdgeImpl {
  override fun setUp(window: Window, view: View, theme: Resources.Theme) {
    WindowCompat.setDecorFitsSystemWindows(window, false)
    val resources = view.resources
    val transparent = ResourcesCompat.getColor(resources, android.R.color.transparent, theme)
    window.statusBarColor = transparent
    val controller = WindowInsetsControllerCompat(window, view)
    controller.isAppearanceLightStatusBars = true
    @Suppress("DEPRECATION")
    window.addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION)
  }
}

@RequiresApi(21)
private class EdgeToEdgeApi21 : EdgeToEdgeImpl {
  override fun setUp(window: Window, view: View, theme: Resources.Theme) {
    WindowCompat.setDecorFitsSystemWindows(window, false)
    @Suppress("DEPRECATION")
    window.addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS)
    @Suppress("DEPRECATION")
    window.addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION)
  }
}

private class EdgeToEdgeBase : EdgeToEdgeImpl {
  override fun setUp(window: Window, view: View, theme: Resources.Theme) {
  }
}

EdgeToEdge.kt - Android Code Search
https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:activity/activity/src/main/java/androidx/activity/EdgeToEdge.kt

Note: This version will only compile against the Android 14 (Upside Down Cake) Beta 1 SDK or higher.
https://developer.android.com/jetpack/androidx/releases/activity#1.8.0-alpha03