platform-specific code

android/app/src/main/kotlin/com/vodemn/lightmeter/MainActivity.kt

@@ -1,6 +1,30 @@
 package com.vodemn.lightmeter
 
+import android.view.WindowManager
 import io.flutter.embedding.android.FlutterActivity
+import io.flutter.embedding.engine.FlutterEngine
+import io.flutter.plugin.common.MethodChannel
 
-class MainActivity: FlutterActivity() {
+class MainActivity : FlutterActivity() {
+    override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
+        super.configureFlutterEngine(flutterEngine)
+        MethodChannel(
+            flutterEngine.dartExecutor.binaryMessenger,
+            "com.vodemn.lightmeter/keepScreenOn"
+        ).setMethodCallHandler { call, result ->
+            when (call.method) {
+                "isKeepScreenOn" -> result.success((window.attributes.flags and WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON) != 0)
+                "setKeepScreenOn" -> {
+                    if (call.arguments !is Boolean) {
+                        result.error("invalid args", "Argument should be of type Bool for 'setKeepScreenOn' call", null)
+                    } else {
+                        if (call.arguments as Boolean) window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
+                        else window.clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
+                        result.success(true)
+                    }
+                }
+                else -> result.notImplemented()
+            }
+        }
+    }
 }

ios/Runner/AppDelegate.swift

@@ -7,6 +7,26 @@ import Flutter
         _ application: UIApplication,
         didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
     ) -> Bool {
+        let controller : FlutterViewController = window?.rootViewController as! FlutterViewController
+        let keepScreenOnChannel = FlutterMethodChannel(name: "com.vodemn.lightmeter/keepScreenOn",
+                                                  binaryMessenger: controller.binaryMessenger)
+        keepScreenOnChannel.setMethodCallHandler({
+          (call: FlutterMethodCall, result: @escaping FlutterResult) -> Void in
+            switch call.method {
+                case "isKeepScreenOn":
+                    result(UIApplication.shared.isIdleTimerDisabled)
+                case "setKeepScreenOn":
+                    guard let keepOn = call.arguments as? Bool else {
+                        result(FlutterError(code: "invalid arguments", message: "Argument should be of type Bool for 'setKeepScreenOn' call", details: nil))
+                        return
+                    }
+                    UIApplication.shared.isIdleTimerDisabled = keepOn
+                    result(true)
+                default:
+                    result(FlutterMethodNotImplemented)
+            }
+        })
+        
         GeneratedPluginRegistrant.register(with: self)
         return super.application(application, didFinishLaunchingWithOptions: launchOptions)
     }