Add platform_view_swift based on platform_view example (#10)

platform_view_swift/lib/main.dart

@@ -0,0 +1,103 @@
+// 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 'dart:async';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+void main() {
+  runApp(new PlatformView());
+}
+
+class PlatformView extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return new MaterialApp(
+      title: 'Platform View',
+      theme: new ThemeData(
+        primarySwatch: Colors.grey,
+      ),
+      home: const MyHomePage(title: 'Platform View'),
+    );
+  }
+}
+
+class MyHomePage extends StatefulWidget {
+  const MyHomePage({Key key, this.title}) : super(key: key);
+
+  final String title;
+
+  @override
+  _MyHomePageState createState() => new _MyHomePageState();
+}
+
+class _MyHomePageState extends State<MyHomePage> {
+  static const MethodChannel _methodChannel =
+      const MethodChannel('samples.flutter.io/platform_view_swift');
+
+  int _counter = 0;
+
+  void _incrementCounter() {
+    setState(() {
+      _counter++;
+    });
+  }
+
+  Future<Null> _launchPlatformCount() async {
+    final int platformCounter =
+        await _methodChannel.invokeMethod('switchView', _counter);
+    setState(() {
+      _counter = platformCounter;
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) => new Scaffold(
+        appBar: new AppBar(
+          title: new Text(widget.title),
+        ),
+        body: new Column(
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: <Widget>[
+            new Expanded(
+              child: new Center(
+                child: new Column(
+                  mainAxisAlignment: MainAxisAlignment.center,
+                  children: <Widget>[
+                    new Text(
+                      'Button tapped $_counter time${ _counter == 1 ? '' : 's' }.',
+                      style: const TextStyle(fontSize: 17.0),
+                    ),
+                    new Padding(
+                      padding: const EdgeInsets.all(18.0),
+                      child: new RaisedButton(
+                          child: const Text('Continue in iOS view'),
+                          onPressed: _launchPlatformCount),
+                    ),
+                  ],
+                ),
+              ),
+            ),
+            new Container(
+              padding: const EdgeInsets.only(bottom: 15.0, left: 5.0),
+              child: new Row(
+                children: <Widget>[
+                  new Image.asset('assets/flutter-mark-square-64.png',
+                      scale: 1.5),
+                  const Text(
+                    'Flutter',
+                    style: const TextStyle(fontSize: 30.0),
+                  ),
+                ],
+              ),
+            ),
+          ],
+        ),
+        floatingActionButton: new FloatingActionButton(
+          onPressed: _incrementCounter,
+          tooltip: 'Increment',
+          child: const Icon(Icons.add),
+        ),
+      );
+}