added widget contents to the Readme.md

README.md

@@ -1,2 +1,232 @@
 # Flutter-Layout-Cheat-Sheet
 This repo includes identified Flutter Layouts which anyone can refer as their layout cheat sheet.
+
+# Widget catalog
+
+
+## Accessibility widgets
+
+## 1.ExcludeSemantics  class
+
+A widget that drops all the semantics of its descendants.
+
+## Properties
+
+[excluding](https://api.flutter.dev/flutter/widgets/ExcludeSemantics/excluding.html)  →  [bool](https://api.flutter.dev/flutter/dart-core/bool-class.html)
+
+Whether this widget is excluded in the semantics tree.
+
+[child](https://api.flutter.dev/flutter/widgets/SingleChildRenderObjectWidget/child.html)  →  [Widget](https://api.flutter.dev/flutter/widgets/Widget-class.html)
+
+The widget below this widget in the tree.  [[...]](https://api.flutter.dev/flutter/widgets/SingleChildRenderObjectWidget/child.html)
+
+[hashCode](https://api.flutter.dev/flutter/dart-core/Object/hashCode.html)  →  [int](https://api.flutter.dev/flutter/dart-core/int-class.html)
+
+The hash code for this object.  [[...]](https://api.flutter.dev/flutter/dart-core/Object/hashCode.html)
+
+[key](https://api.flutter.dev/flutter/widgets/Widget/key.html)  →  [Key](https://api.flutter.dev/flutter/foundation/Key-class.html)
+
+Controls how one widget replaces another widget in the tree.  [[...]](https://api.flutter.dev/flutter/widgets/Widget/key.html)
+
+[runtimeType](https://api.flutter.dev/flutter/dart-core/Object/runtimeType.html)  →  [Type](https://api.flutter.dev/flutter/dart-core/Type-class.html)
+
+A representation of the runtime type of the object.
+
+
+## Operators
+
+[operator ==](https://api.flutter.dev/flutter/dart-core/Object/operator_equals.html)(dynamic  other)  →  [bool](https://api.flutter.dev/flutter/dart-core/bool-class.html)
+
+The equality operator.  [[...]](https://api.flutter.dev/flutter/dart-core/Object/operator_equals.html)
+
+## 2.MergeSemantics  class
+
+A widget that merges the semantics of its descendants
+
+## Properties
+
+[child](https://api.flutter.dev/flutter/widgets/SingleChildRenderObjectWidget/child.html)  →  [Widget](https://api.flutter.dev/flutter/widgets/Widget-class.html)
+
+The widget below this widget in the tree.  [[...]](https://api.flutter.dev/flutter/widgets/SingleChildRenderObjectWidget/child.html)
+
+[hashCode](https://api.flutter.dev/flutter/dart-core/Object/hashCode.html)  →  [int](https://api.flutter.dev/flutter/dart-core/int-class.html)
+
+The hash code for this object.  [[...]](https://api.flutter.dev/flutter/dart-core/Object/hashCode.html)
+
+[key](https://api.flutter.dev/flutter/widgets/Widget/key.html)  →  [Key](https://api.flutter.dev/flutter/foundation/Key-class.html)
+
+Controls how one widget replaces another widget in the tree.  [[...]](https://api.flutter.dev/flutter/widgets/Widget/key.html)
+
+[runtimeType](https://api.flutter.dev/flutter/dart-core/Object/runtimeType.html)  →  [Type](https://api.flutter.dev/flutter/dart-core/Type-class.html)
+
+A representation of the runtime type of the object.
+
+## Operators
+
+[operator ==](https://api.flutter.dev/flutter/dart-core/Object/operator_equals.html)(dynamic  other)  →  [bool](https://api.flutter.dev/flutter/dart-core/bool-class.html)
+
+The equality operator.  [[...]](https://api.flutter.dev/flutter/dart-core/Object/operator_equals.html)
+# Scrolling widgets
+
+## 1.CustomScrollView  class
+
+A  [ScrollView](https://api.flutter.dev/flutter/widgets/ScrollView-class.html)  that creates custom scroll effects using slivers.
+
+This sample code shows a scroll view that contains a flexible pinned app bar, a grid, and an infinite list.
+
+
+```dart
+CustomScrollView(
+  slivers: <Widget>[
+    const SliverAppBar(
+      pinned: true,
+      expandedHeight: 250.0,
+      flexibleSpace: FlexibleSpaceBar(
+        title: Text('Demo'),
+      ),
+    ),
+    SliverGrid(
+      gridDelegate: SliverGridDelegateWithMaxCrossAxisExtent(
+        maxCrossAxisExtent: 200.0,
+        mainAxisSpacing: 10.0,
+        crossAxisSpacing: 10.0,
+        childAspectRatio: 4.0,
+      ),
+      delegate: SliverChildBuilderDelegate(
+        (BuildContext context, int index) {
+          return Container(
+            alignment: Alignment.center,
+            color: Colors.teal[100 * (index % 9)],
+            child: Text('Grid Item $index'),
+          );
+```
+### Accessibility
+A [CustomScrollView](https://api.flutter.dev/flutter/widgets/CustomScrollView-class.html) can allow Talkback/VoiceOver to make announcements to the user when the scroll state changes.
+
+## 2.GridView  class
+A scrollable, 2D array of widgets.
+The main axis direction of a grid is the direction in which it scrolls (the [scrollDirection](https://api.flutter.dev/flutter/widgets/ScrollView/scrollDirection.html)).
+
+### Transitioning to  [CustomScrollView](https://api.flutter.dev/flutter/widgets/CustomScrollView-class.html)
+
+A  [GridView](https://api.flutter.dev/flutter/widgets/GridView-class.html)  is basically a  [CustomScrollView](https://api.flutter.dev/flutter/widgets/CustomScrollView-class.html)  with a single  [SliverGrid](https://api.flutter.dev/flutter/widgets/SliverGrid-class.html)  in its  [CustomScrollView.slivers](https://api.flutter.dev/flutter/widgets/CustomScrollView/slivers.html)  property.
+
+If  [GridView](https://api.flutter.dev/flutter/widgets/GridView-class.html)  is no longer sufficient, for example because the scroll view is to have both a grid and a list, or because the grid is to be combined with a  [SliverAppBar](https://api.flutter.dev/flutter/material/SliverAppBar-class.html), etc, it is straight-forward to port code from using  [GridView](https://api.flutter.dev/flutter/widgets/GridView-class.html)  to using  [CustomScrollView](https://api.flutter.dev/flutter/widgets/CustomScrollView-class.html)  directly
+
+Sample
+
+This example demonstrates how to create a  [GridView](https://api.flutter.dev/flutter/widgets/GridView-class.html)  with two columns. The children are spaced apart using the  `crossAxisSpacing`  and  `mainAxisSpacing`  properties.
+
+![A screenshot of a GridView](https://flutter.github.io/assets-for-api-docs/assets/widgets/grid_view.png)
+
+_assignment_
+
+```dart
+GridView.count(
+  primary: false,
+  padding: const EdgeInsets.all(20),
+  crossAxisSpacing: 10,
+  mainAxisSpacing: 10,
+  crossAxisCount: 2,
+  children: <Widget>[
+    Container(
+      padding: const EdgeInsets.all(8),
+      child: const Text('He\'d have you all unravel at the'),
+      color: Colors.teal[100],
+    ),
+    Container(
+      padding: const EdgeInsets.all(8),
+      child: const Text('Heed not the rabble'),
+      color: Colors.teal[200],
+    ),
+    Container(
+      padding: const EdgeInsets.all(8),
+      child: const Text('Sound of screams but the'),
+      color: Colors.teal[300],
+    ),
+    Container(
+      padding: const EdgeInsets.all(8),
+      child: const Text('Who scream'),
+      color: Colors.teal[400],
+    ),
+    Container(
+      padding: const EdgeInsets.all(8),
+      child: const Text('Revolution is coming...'),
+      color: Colors.teal[500],
+    ),
+    Container(
+      padding: const EdgeInsets.all(8),
+      child: const Text('Revolution, they...'),
+      color: Colors.teal[600],
+    ),
+  ],
+)
+```
+
+
+Sample
+
+This example shows how to create the same grid as the previous example using a  [CustomScrollView](https://api.flutter.dev/flutter/widgets/CustomScrollView-class.html)  and a  [SliverGrid](https://api.flutter.dev/flutter/widgets/SliverGrid-class.html).
+
+![A screenshot of a CustomScrollView with a SliverGrid](https://flutter.github.io/assets-for-api-docs/assets/widgets/grid_view_custom_scroll.png)
+
+
+```dart
+CustomScrollView(
+  primary: false,
+  slivers: <Widget>[
+    SliverPadding(
+      padding: const EdgeInsets.all(20),
+      sliver: SliverGrid.count(
+        crossAxisSpacing: 10,
+        mainAxisSpacing: 10,
+        crossAxisCount: 2,
+        children: <Widget>[
+          Container(
+            padding: const EdgeInsets.all(8),
+            child: const Text('He\'d have you all unravel at the'),
+            color: Colors.green[100],
+          ),
+          Container(
+            padding: const EdgeInsets.all(8),
+            child: const Text('Heed not the rabble'),
+            color: Colors.green[200],
+          ),
+          Container(
+            padding: const EdgeInsets.all(8),
+            child: const Text('Sound of screams but the'),
+            color: Colors.green[300],
+```
+
+## 3.ListView  class
+
+A scrollable list of widgets arranged linearly.
+Sample
+
+This example uses the default constructor for  [ListView](https://api.flutter.dev/flutter/widgets/ListView-class.html)  which takes an explicit  [List<Widget>](https://api.flutter.dev/flutter/dart-core/List-class.html)  of children. This  [ListView](https://api.flutter.dev/flutter/widgets/ListView-class.html)'s children are made up of  [Container](https://api.flutter.dev/flutter/widgets/Container-class.html)s with  [Text](https://api.flutter.dev/flutter/widgets/Text-class.html).
+
+![A ListView of 3 amber colored containers with sample text.](https://flutter.github.io/assets-for-api-docs/assets/widgets/list_view.png)
+
+
+```dart
+ListView(
+  padding: const EdgeInsets.all(8),
+  children: <Widget>[
+    Container(
+      height: 50,
+      color: Colors.amber[600],
+      child: const Center(child: Text('Entry A')),
+    ),
+    Container(
+      height: 50,
+      color: Colors.amber[500],
+      child: const Center(child: Text('Entry B')),
+    ),
+    Container(
+      height: 50,
+      color: Colors.amber[100],
+      child: const Center(child: Text('Entry C')),
+    ),
+  ],
+)
+```