add default color to WidgetsApp samples

Samples/UIWidgetsSamples_2019_4/Assets/Script/CountTest.cs

             {
                 return new WidgetsApp(
                     home: new ExampleApp(),
+                    color: Color.white,
                     pageRouteBuilder: (settings, builder) =>
                         new PageRouteBuilder(
                             settings: settings,

Samples/UIWidgetsSamples_2019_4/Assets/WidgetsSample/CustomPaintSample.cs

             public override Widget build(BuildContext context)
             {
                 return new WidgetsApp(
+                    color: Color.white,
                     home: new Unity.UIWidgets.widgets.CustomPaint(
                         child: new Container(width: 300, height: 300, color: new Color(0XFFFFFFFF)),
                         foregroundPainter: new GridPainter(null)

Samples/UIWidgetsSamples_2019_4/Assets/WidgetsSample/DragDropSample.cs

 using Unity.UIWidgets.ui;
 using Unity.UIWidgets.widgets;
 using UnityEngine;
+using Color = Unity.UIWidgets.ui.Color;
 using ui_ = Unity.UIWidgets.widgets.ui_;
 
 namespace UIWidgetsSample {
             public override Widget build(BuildContext context)
             {
                 return new WidgetsApp(
+                    color: Color.white,
                     home: new DragDropApp(),
                     pageRouteBuilder: (settings, builder) =>
                         new PageRouteBuilder(

Samples/UIWidgetsSamples_2019_4/Assets/WidgetsSample/HttpRequestSample.cs

 using UnityEngine.Networking;
 using ui_ = Unity.UIWidgets.widgets.ui_;
 
-public class HttpRequestSample : UIWidgetsPanel
+namespace UIWidgetsSample
-    protected override void main() {
-        ui_.runApp(new MaterialApp(
-            title: "Http Request Sample",
-            home: new Scaffold(
-                body:new AsyncRequestWidget(this.gameObject)
+    public class HttpRequestSample : UIWidgetsPanel
+    {
+        protected override void main()
+        {
+            ui_.runApp(new MaterialApp(
+                title: "Http Request Sample",
+                home: new Scaffold(
+                    body: new AsyncRequestWidget(this.gameObject)
-        ));
+            ));
+        }
-}
-public class AsyncRequestWidget : StatefulWidget {
-    
-    public readonly GameObject gameObjOfUIWidgetsPanel;
+    public class AsyncRequestWidget : StatefulWidget
+    {
-    public AsyncRequestWidget(GameObject gameObjOfUiWidgetsPanel, Key key = null) : base(key) {
-        this.gameObjOfUIWidgetsPanel = gameObjOfUiWidgetsPanel;
+        public readonly GameObject gameObjOfUIWidgetsPanel;
+
+        public AsyncRequestWidget(GameObject gameObjOfUiWidgetsPanel, Key key = null) : base(key)
+        {
+            this.gameObjOfUIWidgetsPanel = gameObjOfUiWidgetsPanel;
+        }
+
+        public override State createState()
+        {
+            return new _AsyncRequestWidgetState();
+        }
-    public override State createState() {
-        return new _AsyncRequestWidgetState();
+    [Serializable]
+    public class TimeData
+    {
+        public long currentFileTime;
-}
-[Serializable]
-public class TimeData {
-    public long currentFileTime;
-}
+    class _AsyncRequestWidgetState : State<AsyncRequestWidget>
+    {
+
+        long _fileTime;
+
+        public override Widget build(BuildContext context)
+        {
+            var isolate = Isolate.current;
-class _AsyncRequestWidgetState : State<AsyncRequestWidget> {
-    
-    long _fileTime;
-    
-    public override Widget build(BuildContext context) {
-        var isolate = Isolate.current;
-        
-        return new Column(
-            crossAxisAlignment: CrossAxisAlignment.start,
-            children: new List<Widget>() {
-                new FlatButton(child: new Text("Click To Get Time"), onPressed: () => {
-                    UnityWebRequest www = UnityWebRequest.Get("http://worldclockapi.com/api/json/est/now");
-                    var asyncOperation  = www.SendWebRequest();
-                    asyncOperation.completed += operation => {
-                        var timeData = JsonUtility.FromJson<TimeData>(www.downloadHandler.text);
-                        using(Isolate.getScope(isolate))
+            return new Column(
+                crossAxisAlignment: CrossAxisAlignment.start,
+                children: new List<Widget>()
+                {
+                    new FlatButton(child: new Text("Click To Get Time"), onPressed: () =>
+                    {
+                        UnityWebRequest www = UnityWebRequest.Get("http://worldclockapi.com/api/json/est/now");
+                        var asyncOperation = www.SendWebRequest();
+                        asyncOperation.completed += operation =>
-                            this.setState(() => { this._fileTime = timeData.currentFileTime; });
-                        }
-                       
-                    };
-                }),
-                new Text($"current file time: {this._fileTime}")
-            });
+                            var timeData = JsonUtility.FromJson<TimeData>(www.downloadHandler.text);
+                            using (Isolate.getScope(isolate))
+                            {
+                                this.setState(() => { this._fileTime = timeData.currentFileTime; });
+                            }
+
+                        };
+                    }),
+                    new Text($"current file time: {this._fileTime}")
+                });
+        }
     }
 }

Samples/UIWidgetsSamples_2019_4/Assets/WidgetsSample/LongPressSample.cs

 using Unity.UIWidgets.engine2;
 using Unity.UIWidgets.widgets;
 using UnityEngine;
+using Color = Unity.UIWidgets.ui.Color;
 
 namespace UIWidgetsSample {
     public class LongPressSample : UIWidgetsPanel {
         public override Widget build(BuildContext context)
         {
             return new WidgetsApp(
+                color: Color.white,
                 home: new LongPressSampleWidget(),
                 pageRouteBuilder: (settings, builder) =>
                     new PageRouteBuilder(

Samples/UIWidgetsSamples_2019_4/Assets/WidgetsSample/NavigationSample.cs

             public override Widget build(BuildContext context)
             {
                 return new WidgetsApp(
+                    color: Color.white,
                     initialRoute: "/",
                     textStyle: new TextStyle(fontSize: 24),
                     pageRouteBuilder: (settings, builder) =>

Samples/UIWidgetsSamples_2019_4/Assets/WidgetsSample/PageViewSample.cs

             public override Widget build(BuildContext context)
             {
                 return new WidgetsApp(
+                    color: Color.white,
                     home: new Container(
                         width: 200,
                         height: 400,

Samples/UIWidgetsSamples_2019_4/Assets/WidgetsSample/ScrollbarSample.cs

             public override Widget build(BuildContext context)
             {
                 return new WidgetsApp(
+                    color: Color.white,
                     home: new Container(
                         decoration: new BoxDecoration(
                             border: Border.all(color: new Color(0xFFFFFF00))

Samples/UIWidgetsSamples_2019_4/Assets/WidgetsSample/ToDoAppSample.cs

         {
             ui_.runApp(
                 new WidgetsApp(
+                    color: Color.white,
                     home: new ToDoListApp(),
                     pageRouteBuilder: this.pageRouteBuilder)
             );

Samples/UIWidgetsSamples_2019_4/Assets/WidgetsSample/ImageFormatSample.cs

+using System.Collections.Generic;
+using uiwidgets;
+using Unity.UIWidgets.engine2;
+using Unity.UIWidgets.painting;
+using Unity.UIWidgets.ui;
+using Unity.UIWidgets.widgets;
+using Image = Unity.UIWidgets.widgets.Image;
+using ui_ = Unity.UIWidgets.widgets.ui_;
+
+namespace UIWidgetsSample
+{
+    public class ImageFormatSample : UIWidgetsPanel
+    {
+        protected override void main()
+        {
+            ui_.runApp(new MyApp());
+        }
+
+        class MyApp : StatelessWidget
+        {
+            public override Widget build(BuildContext context)
+            {
+                return new WidgetsApp(
+                    home: new ImageFormatApp(),
+                    color: Color.white,
+                    pageRouteBuilder: (settings, builder) =>
+                        new PageRouteBuilder(
+                            settings: settings,
+                            pageBuilder: (buildContext, animation, secondaryAnimation) => builder(context)
+                        )
+                );
+            }
+        }
+
+        class ImageFormatApp : StatefulWidget
+        {
+            public override State createState()
+            {
+                return new ImageFormatAppState();
+            }
+        }
+
+        class ImageFormatAppState : State<ImageFormatApp>
+        {
+            private int imageId;
+
+            private static List<string> imagePath = new List<string>
+            {
+                "shrine_images/0-0.jpg",
+                "shrine_images/2.0x/1-0.jpg",
+                "shrine_images/diamond.png",
+                "gallery/people/square/ali.png",
+                "gallery/10-0.jpg",
+                "gallery/glasses.jpg"
+            };
+
+
+            public override Widget build(BuildContext context)
+            {
+                return new Container(
+                    child: new Column(
+                        children: new List<Widget>
+                        {
+                            new Container(
+                                width: 100,
+                                height: 100,
+                                decoration: new BoxDecoration(
+                                    borderRadius: BorderRadius.all(Radius.circular(8))
+                                ),
+                                child: Image.file(imagePath[imageId])
+                            ),
+                            new Text(imagePath[imageId]),
+                            new GestureDetector(
+                                onTap: () => { setState(() => { imageId = (imageId + 1) % imagePath.Count; }); },
+                                child: new Container(
+                                    color: Color.black,
+                                    padding: EdgeInsets.symmetric(20, 20),
+                                    child: new Text("Next"
+                                )
+                            ))
+                        }
+                        ));
+            }
+        }
+    }
+    
+    
+}