Added widget content

README.md

@@ -1,2 +1,220 @@
 # Flutter-Layout-Cheat-Sheet
 This repo includes identified Flutter Layouts which anyone can refer as their layout cheat sheet.
+
+# AnimatedBuilder  class
+
+A general-purpose widget for building animations.
+
+## Performance optimizations
+
+If your  [builder](https://api.flutter.dev/flutter/widgets/AnimatedBuilder/builder.html)  function contains a subtree that does not depend on the animation, it's more efficient to build that subtree once instead of rebuilding it on every animation tick.
+
+If you pass the pre-built subtree as the  [child](https://api.flutter.dev/flutter/widgets/AnimatedBuilder/child.html)  parameter, the AnimatedBuilder will pass it back to your builder function so that you can incorporate it into your build.
+
+Using this pre-built child is entirely optional, but can improve performance significantly in some cases and is therefore a good practice.
+
+[_link_](https://api.flutter.dev/flutter/# "Copy link to clipboard")
+
+Sample
+
+This code defines a widget called  `Spinner`  that spins a green square continually. It is built with an  [AnimatedBuilder](https://api.flutter.dev/flutter/widgets/AnimatedBuilder-class.html)  and makes use of the  [child](https://api.flutter.dev/flutter/widgets/AnimatedBuilder/child.html)  feature to avoid having to rebuild the  [Container](https://api.flutter.dev/flutter/widgets/Container-class.html)  each time.
+
+_assignment_
+
+```dart
+class Spinner extends StatefulWidget {
+  @override
+  _SpinnerState createState() => _SpinnerState();
+}
+
+class _SpinnerState extends State<Spinner> with SingleTickerProviderStateMixin {
+  AnimationController _controller;
+
+  @override
+  void initState() {
+    super.initState();
+    _controller = AnimationController(
+      duration: const Duration(seconds: 10),
+      vsync: this,
+    )..repeat();
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AnimatedBuilder(
+      animation: _controller,
+      child: Container(width: 200.0, height: 200.0, color: Colors.green),
+      builder: (BuildContext context, Widget child) {
+        return Transform.rotate(
+          angle: _controller.value * 2.0 * math.pi,
+          child: child,
+        );
+      },
+    );
+  }
+}
+```
+
+Inheritance
+
+-   [Object](https://api.flutter.dev/flutter/dart-core/Object-class.html)
+-   [Diagnosticable](https://api.flutter.dev/flutter/foundation/Diagnosticable-class.html)
+-   [DiagnosticableTree](https://api.flutter.dev/flutter/foundation/DiagnosticableTree-class.html)
+-   [Widget](https://api.flutter.dev/flutter/widgets/Widget-class.html)
+-   [StatefulWidget](https://api.flutter.dev/flutter/widgets/StatefulWidget-class.html)
+-   [AnimatedWidget](https://api.flutter.dev/flutter/widgets/AnimatedWidget-class.html)
+-   AnimatedBuilder
+
+## Constructors
+
+[AnimatedBuilder](https://api.flutter.dev/flutter/widgets/AnimatedBuilder/AnimatedBuilder.html)({[Key](https://api.flutter.dev/flutter/foundation/Key-class.html)  key, @required  [Listenable](https://api.flutter.dev/flutter/foundation/Listenable-class.html)  animation, @required  [TransitionBuilder](https://api.flutter.dev/flutter/widgets/TransitionBuilder.html)  builder, [Widget](https://api.flutter.dev/flutter/widgets/Widget-class.html)  child  })
+
+Creates an animated builder.  [[...]](https://api.flutter.dev/flutter/widgets/AnimatedBuilder/AnimatedBuilder.html)
+
+const
+
+## Properties
+
+[builder](https://api.flutter.dev/flutter/widgets/AnimatedBuilder/builder.html)  →  [TransitionBuilder](https://api.flutter.dev/flutter/widgets/TransitionBuilder.html)
+
+Called every time the animation changes value.
+
+final
+
+[child](https://api.flutter.dev/flutter/widgets/AnimatedBuilder/child.html)  →  [Widget](https://api.flutter.dev/flutter/widgets/Widget-class.html)
+
+The child widget to pass to the  [builder](https://api.flutter.dev/flutter/widgets/AnimatedBuilder/builder.html).  [[...]](https://api.flutter.dev/flutter/widgets/AnimatedBuilder/child.html)
+
+final
+
+[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)
+
+read-only, inherited
+
+[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)
+
+final, inherited
+
+[listenable](https://api.flutter.dev/flutter/widgets/AnimatedWidget/listenable.html)  →  [Listenable](https://api.flutter.dev/flutter/foundation/Listenable-class.html)
+
+The  [Listenable](https://api.flutter.dev/flutter/foundation/Listenable-class.html)  to which this widget is listening.  [[...]](https://api.flutter.dev/flutter/widgets/AnimatedWidget/listenable.html)
+
+final, inherited
+
+[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.
+
+read-only, inherited
+
+## Methods
+
+[build](https://api.flutter.dev/flutter/widgets/AnimatedBuilder/build.html)([BuildContext](https://api.flutter.dev/flutter/widgets/BuildContext-class.html)  context)  →  [Widget](https://api.flutter.dev/flutter/widgets/Widget-class.html)
+
+Override this method to build widgets that depend on the state of the listenable (e.g., the current value of the animation).
+
+override
+
+[createElement](https://api.flutter.dev/flutter/widgets/StatefulWidget/createElement.html)()  →  [StatefulElement](https://api.flutter.dev/flutter/widgets/StatefulElement-class.html)
+
+Creates a  [StatefulElement](https://api.flutter.dev/flutter/widgets/StatefulElement-class.html)  to manage this widget's location in the tree.  [[...]](https://api.flutter.dev/flutter/widgets/StatefulWidget/createElement.html)
+
+inherited
+
+[createState](https://api.flutter.dev/flutter/widgets/AnimatedWidget/createState.html)()  → _AnimatedState
+
+Subclasses typically do not override this method.
+
+inherited
+
+[debugDescribeChildren](https://api.flutter.dev/flutter/foundation/DiagnosticableTree/debugDescribeChildren.html)()  →  [List](https://api.flutter.dev/flutter/dart-core/List-class.html)<[DiagnosticsNode](https://api.flutter.dev/flutter/foundation/DiagnosticsNode-class.html)>
+
+Returns a list of  [DiagnosticsNode](https://api.flutter.dev/flutter/foundation/DiagnosticsNode-class.html)  objects describing this node's children.  [[...]](https://api.flutter.dev/flutter/foundation/DiagnosticableTree/debugDescribeChildren.html)
+
+@protected, inherited
+
+[debugFillProperties](https://api.flutter.dev/flutter/widgets/AnimatedWidget/debugFillProperties.html)([DiagnosticPropertiesBuilder](https://api.flutter.dev/flutter/foundation/DiagnosticPropertiesBuilder-class.html)  properties)  → void
+
+Add additional properties associated with the node.  [[...]](https://api.flutter.dev/flutter/widgets/AnimatedWidget/debugFillProperties.html)
+
+inherited
+
+[noSuchMethod](https://api.flutter.dev/flutter/dart-core/Object/noSuchMethod.html)([Invocation](https://api.flutter.dev/flutter/dart-core/Invocation-class.html)  invocation)  → dynamic
+
+Invoked when a non-existent method or property is accessed.  [[...]](https://api.flutter.dev/flutter/dart-core/Object/noSuchMethod.html)
+
+inherited
+
+[toDiagnosticsNode](https://api.flutter.dev/flutter/foundation/DiagnosticableTree/toDiagnosticsNode.html)({[String](https://api.flutter.dev/flutter/dart-core/String-class.html)  name, [DiagnosticsTreeStyle](https://api.flutter.dev/flutter/foundation/DiagnosticsTreeStyle-class.html)  style  })  →  [DiagnosticsNode](https://api.flutter.dev/flutter/foundation/DiagnosticsNode-class.html)
+
+Returns a debug representation of the object that is used by debugging tools and by  [DiagnosticsNode.toStringDeep](https://api.flutter.dev/flutter/foundation/DiagnosticableTree/toStringDeep.html).  [[...]](https://api.flutter.dev/flutter/foundation/DiagnosticableTree/toDiagnosticsNode.html)
+
+inherited
+
+[toString](https://api.flutter.dev/flutter/foundation/DiagnosticableMixin/toString.html)({[DiagnosticLevel](https://api.flutter.dev/flutter/foundation/DiagnosticLevel-class.html)  minLevel:  DiagnosticLevel.debug  })  →  [String](https://api.flutter.dev/flutter/dart-core/String-class.html)
+
+Returns a string representation of this object.
+
+inherited
+
+[toStringDeep](https://api.flutter.dev/flutter/foundation/DiagnosticableTree/toStringDeep.html)({[String](https://api.flutter.dev/flutter/dart-core/String-class.html)  prefixLineOne:  '', [String](https://api.flutter.dev/flutter/dart-core/String-class.html)  prefixOtherLines, [DiagnosticLevel](https://api.flutter.dev/flutter/foundation/DiagnosticLevel-class.html)  minLevel:  DiagnosticLevel.debug  })  →  [String](https://api.flutter.dev/flutter/dart-core/String-class.html)
+
+Returns a string representation of this node and its descendants.  [[...]](https://api.flutter.dev/flutter/foundation/DiagnosticableTree/toStringDeep.html)
+
+inherited
+
+[toStringShallow](https://api.flutter.dev/flutter/foundation/DiagnosticableTree/toStringShallow.html)({[String](https://api.flutter.dev/flutter/dart-core/String-class.html)  joiner:  ', ', [DiagnosticLevel](https://api.flutter.dev/flutter/foundation/DiagnosticLevel-class.html)  minLevel:  DiagnosticLevel.debug  })  →  [String](https://api.flutter.dev/flutter/dart-core/String-class.html)
+
+Returns a one-line detailed description of the object.  [[...]](https://api.flutter.dev/flutter/foundation/DiagnosticableTree/toStringShallow.html)
+
+inherited
+
+[toStringShort](https://api.flutter.dev/flutter/widgets/Widget/toStringShort.html)()  →  [String](https://api.flutter.dev/flutter/dart-core/String-class.html)
+
+A short, textual description of this widget.
+
+inherited
+
+## 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)
+
+inherited
+
+1.  [CONSTRUCTORS](https://api.flutter.dev/flutter/widgets/AnimatedBuilder-class.html#constructors)
+2.  [AnimatedBuilder](https://api.flutter.dev/flutter/widgets/AnimatedBuilder/AnimatedBuilder.html)
+3.  [PROPERTIES](https://api.flutter.dev/flutter/widgets/AnimatedBuilder-class.html#instance-properties)
+4.  [builder](https://api.flutter.dev/flutter/widgets/AnimatedBuilder/builder.html)
+5.  [child](https://api.flutter.dev/flutter/widgets/AnimatedBuilder/child.html)
+6.  [hashCode](https://api.flutter.dev/flutter/dart-core/Object/hashCode.html)
+7.  [key](https://api.flutter.dev/flutter/widgets/Widget/key.html)
+8.  [listenable](https://api.flutter.dev/flutter/widgets/AnimatedWidget/listenable.html)
+9.  [runtimeType](https://api.flutter.dev/flutter/dart-core/Object/runtimeType.html)
+10.  [METHODS](https://api.flutter.dev/flutter/widgets/AnimatedBuilder-class.html#instance-methods)
+11.  [build](https://api.flutter.dev/flutter/widgets/AnimatedBuilder/build.html)
+12.  [createElement](https://api.flutter.dev/flutter/widgets/StatefulWidget/createElement.html)
+13.  [createState](https://api.flutter.dev/flutter/widgets/AnimatedWidget/createState.html)
+14.  [debugDescribeChildren](https://api.flutter.dev/flutter/foundation/DiagnosticableTree/debugDescribeChildren.html)
+15.  [debugFillProperties](https://api.flutter.dev/flutter/widgets/AnimatedWidget/debugFillProperties.html)
+16.  [noSuchMethod](https://api.flutter.dev/flutter/dart-core/Object/noSuchMethod.html)
+17.  [toDiagnosticsNode](https://api.flutter.dev/flutter/foundation/DiagnosticableTree/toDiagnosticsNode.html)
+18.  [toString](https://api.flutter.dev/flutter/foundation/DiagnosticableMixin/toString.html)
+19.  [toStringDeep](https://api.flutter.dev/flutter/foundation/DiagnosticableTree/toStringDeep.html)
+20.  [toStringShallow](https://api.flutter.dev/flutter/foundation/DiagnosticableTree/toStringShallow.html)
+21.  [toStringShort](https://api.flutter.dev/flutter/widgets/Widget/toStringShort.html)
+22.  [OPERATORS](https://api.flutter.dev/flutter/widgets/AnimatedBuilder-class.html#operators)
+23.  [operator ==](https://api.flutter.dev/flutter/dart-core/Object/operator_equals.html)
+
+Flutter 1.9.1+hotfix.5 •