Add workflow to deploy the sample index (#791)

* Add workflow to build and deploy the sample index

* update gh-pages action

* fix yaml

* create web/ directory in build

* grammar

* add ignored directories

* revert pubspec.lock files

* add job to run _tool/verify_samples.dart

* Update filipino_cuisine for Flutter 2

* remove timeflow demo.

The unnamed List constructor is now deprecated, refactoring
this code to use add() requires more knowledge about the code for
this demo.
https://dart.dev/null-safety/understanding-null-safety#no-unnamed-list-constructor

* update slide_puzzle

* ensure stable channel is used to verify

* move verify web demos action into separate yaml file - avoid running
on each flutter version.

* add on: pull_request

* update slide_puzzle

* Update gh-pages.yml

* Add copyright header

web/github_dataviz/lib/catmull.dart

@@ -60,7 +60,7 @@ class CatmullInterpolator implements Interpolator {
   }
 
   static void test() {
-    List<Point2D> controlPoints = List<Point2D>();
+    List<Point2D> controlPoints = <Point2D>[];
     controlPoints.add(Point2D(-1, 1));
     controlPoints.add(Point2D(0, 1));
     controlPoints.add(Point2D(1, -1));

web/github_dataviz/lib/layered_chart.dart

@@ -47,12 +47,12 @@ class LayeredChartState extends State<LayeredChart> {
     graphHeight = MathUtils.clampedMap(screenRatio, 0.5, 2.5, 50, 150);
 
     int m = dataToPlot.length;
-    paths = List<Path>(m);
-    capPaths = List<Path>(m);
-    maxValues = List<double>(m);
+    paths = <Path>[];
+    capPaths = <Path>[];
+    maxValues = <double>[];
     for (int i = 0; i < m; i++) {
       int n = dataToPlot[i].series.length;
-      maxValues[i] = 0;
+      maxValues.add(0);
       for (int j = 0; j < n; j++) {
         double v = dataToPlot[i].series[j].toDouble();
         if (v > maxValues[i]) {
@@ -69,11 +69,11 @@ class LayeredChartState extends State<LayeredChart> {
     double xWidth = (endX - startX) / numPoints;
     double capRangeX = capSize * cos(capTheta);
     double tanCapTheta = tan(capTheta);
-    List<double> curvePoints = List<double>(numPoints);
+    List<double> curvePoints = <double>[];
     for (int i = 0; i < m; i++) {
       List<int> series = dataToPlot[i].series;
       int n = series.length;
-      List<Point2D> controlPoints = List<Point2D>();
+      List<Point2D> controlPoints = <Point2D>[];
       controlPoints.add(Point2D(-1, 0));
       double last = 0;
       for (int j = 0; j < n; j++) {
@@ -88,11 +88,11 @@ class LayeredChartState extends State<LayeredChart> {
         cpv.value = MathUtils.map(
             j.toDouble(), 0, (numPoints - 1).toDouble(), 0, (n - 1).toDouble());
         curve.progressiveGet(cpv);
-        curvePoints[j] = MathUtils.map(
-            max(0, cpv.value), 0, maxValues[i].toDouble(), 0, graphHeight);
+        curvePoints.add(MathUtils.map(
+            max(0, cpv.value), 0, maxValues[i].toDouble(), 0, graphHeight));
       }
-      paths[i] = Path();
-      capPaths[i] = Path();
+      paths.add(Path());
+      capPaths.add(Path());
       paths[i].moveTo(startX, startY);
       capPaths[i].moveTo(startX, startY);
       for (int j = 0; j < numPoints; j++) {
@@ -133,7 +133,7 @@ class LayeredChartState extends State<LayeredChart> {
       capPaths[i].lineTo(startX, startY + 1);
       capPaths[i].close();
     }
-    labelPainter = List<TextPainter>();
+    labelPainter = <TextPainter>[];
     for (int i = 0; i < dataToPlot.length; i++) {
       TextSpan span = TextSpan(
           style: TextStyle(
@@ -146,7 +146,7 @@ class LayeredChartState extends State<LayeredChart> {
       tp.layout();
       labelPainter.add(tp);
     }
-    milestonePainter = List<TextPainter>();
+    milestonePainter = <TextPainter>[];
     for (int i = 0; i < milestones.length; i++) {
       TextSpan span = TextSpan(
           style: TextStyle(

web/github_dataviz/lib/main.dart

@@ -46,7 +46,7 @@ class _MainLayoutState extends State<MainLayout> with TickerProviderStateMixin {
 
     createAnimation(0);
 
-    weekLabels = List();
+    weekLabels = <WeekLabel>[];
     weekLabels.add(WeekLabel.forDate(DateTime(2019, 2, 26), "v1.2"));
     weekLabels.add(WeekLabel.forDate(DateTime(2018, 12, 4), "v1.0"));
 //    weekLabels.add(WeekLabel.forDate(new DateTime(2018, 9, 19), "Preview 2"));
@@ -79,9 +79,9 @@ class _MainLayoutState extends State<MainLayout> with TickerProviderStateMixin {
   @override
   Widget build(BuildContext context) {
     // Combined contributions data
-    List<DataSeries> dataToPlot = List();
+    List<DataSeries> dataToPlot = [];
     if (contributions != null) {
-      List<int> series = List();
+      List<int> series = [];
       for (UserContribution userContrib in contributions) {
         for (int i = 0; i < userContrib.contributions.length; i++) {
           ContributionData data = userContrib.contributions[i];
@@ -228,7 +228,7 @@ class _MainLayoutState extends State<MainLayout> with TickerProviderStateMixin {
 
   List<StatForWeek> summarizeWeeksFromTSV(
       String statByWeekStr, int numWeeksTotal) {
-    List<StatForWeek> loadedStats = List();
+    List<StatForWeek> loadedStats = [];
     HashMap<int, StatForWeek> statMap = HashMap();
     statByWeekStr.split("\n").forEach((s) {
       List<String> split = s.split("\t");
@@ -237,7 +237,8 @@ class _MainLayoutState extends State<MainLayout> with TickerProviderStateMixin {
         statMap[weekNum] = StatForWeek(weekNum, int.parse(split[1]));
       }
     });
-    print("Laoded ${statMap.length} weeks.");
+    print("Loaded ${statMap.length} weeks.");
+
     // Convert into a list by week, but fill in empty weeks with 0
     for (int i = 0; i < numWeeksTotal; i++) {
       StatForWeek starsForWeek = statMap[i];

web/github_dataviz/pubspec.lock

@@ -7,7 +7,7 @@ packages:
       name: characters
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.5"
+    version: "1.1.0"
   charcode:
     dependency: transitive
     description:
@@ -21,7 +21,7 @@ packages:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.15.0-nullsafety.5"
+    version: "1.15.0"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -54,7 +54,7 @@ packages:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.6"
+    version: "1.3.0"
   path:
     dependency: transitive
     description:
@@ -101,13 +101,13 @@ packages:
       name: typed_data
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.5"
+    version: "1.3.0"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.5"
+    version: "2.1.0"
 sdks:
   dart: ">=2.12.0-0 <3.0.0"