Add platform_view_swift based on platform_view example (#10)

platform_view_swift/ios/Runner/AppDelegate.swift

@@ -0,0 +1,43 @@
+// Copyright 2018, the Flutter project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import UIKit
+import Flutter
+
+@UIApplicationMain
+@objc class AppDelegate: FlutterAppDelegate, PlatformViewControllerDelegate
+{
+  var flutterResult: FlutterResult?
+
+  override func application(
+    _ application: UIApplication,
+    didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
+    GeneratedPluginRegistrant.register(with: self)
+    let controller: FlutterViewController = window?.rootViewController as! FlutterViewController
+    let channel = FlutterMethodChannel.init(name: "samples.flutter.io/platform_view_swift", binaryMessenger: controller)
+
+    channel.setMethodCallHandler({
+      (call: FlutterMethodCall, result: @escaping FlutterResult) -> Void in
+      if ("switchView" == call.method) {
+        self.flutterResult = result
+
+        let platformViewController = controller.storyboard?.instantiateViewController(withIdentifier: "PlatformView") as! PlatformViewController
+        platformViewController.counter = call.arguments as! Int
+        platformViewController.delegate = self
+
+        let navigationController = UINavigationController(rootViewController: platformViewController)
+        navigationController.navigationBar.topItem?.title = "Platform View"
+        controller.present(navigationController, animated: true, completion: nil)
+      } else {
+        result(FlutterMethodNotImplemented)
+      }
+    });
+
+    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
+  }
+
+  func didUpdateCounter(counter: Int) {
+    flutterResult?(counter)
+  }
+}