Update README.md

Author: 2534290808

README.md

@@ -1,14 +1,78 @@
+English | [简体中文](./README_zh-CN.md)
+
 # animated_interpolation
 
-A new Flutter package.
+[![pub package](https://img.shields.io/pub/v/animated_interpolation.svg)](https://pub.dartlang.org/packages/animated_interpolation)
+
+A flutter interpolation animation inspired by the React Native interpolation animation
+
+
+## Usage
+To use this plugin, add `animated_interpolation` as a [dependency in your pubspec.yaml file](https://flutter.io/platform-plugins/).
+
+## Example
+
+``` dart
+import 'package:flutter/material.dart';
+import 'package:animated_interpolation/animated_interpolation.dart';
+class AnimatedLogo1 extends AnimatedWidget {
+  // The Tweens are static because they don't change.
+  static final _opacityTween = new InterpolationTween<double>(inputRange: [0,0.2,1], outputRange: [0,0.5,1]);
+  static final _sizeTween = new InterpolationTween(inputRange: [0,0.2,1], outputRange: [0,250,300]);
+
+  AnimatedLogo1({Key key, Animation<double> animation})
+      : super(key: key, listenable: animation);
+
+  Widget build(BuildContext context) {
+    final Animation<double> animation = listenable;
+    return new Center(
+      child: new Opacity(
+        opacity: _opacityTween.evaluate(animation),
+        child: new Container(
+          margin: new EdgeInsets.symmetric(vertical: 10.0),
+          height: _sizeTween.evaluate(animation),
+          width: _sizeTween.evaluate(animation),
+          child: new FlutterLogo(),
+        ),
+      ),
+    );
+  }
+}
+
+class LogoApp4 extends StatefulWidget {
+  _LogoAppState createState() => new _LogoAppState();
+}
+
+class _LogoAppState extends State<LogoApp4> with TickerProviderStateMixin {
+  AnimationController controller;
+  Animation<double> animation;
+
+  initState() {
+    super.initState();
+    controller = new AnimationController(
+        duration: const Duration(milliseconds: 2000), vsync: this);
+    animation = new CurvedAnimation(parent: controller, curve: Curves.easeIn);
+
+
+    animation.addStatusListener((status) {
+      if (status == AnimationStatus.completed) {
+        controller.reverse();
+      } else if (status == AnimationStatus.dismissed) {
+        controller.forward();
+      }
+    });
 
-## Getting Started
+    controller.forward();
+  }
 
-This project is a starting point for a Dart
-[package](https://flutter.dev/developing-packages/),
-a library module containing code that can be shared easily across
-multiple Flutter or Dart projects.
+  Widget build(BuildContext context) {
+    return new AnimatedLogo1(animation: animation);
+  }
 
-For help getting started with Flutter, view our 
-[online documentation](https://flutter.dev/docs), which offers tutorials, 
-samples, guidance on mobile development, and a full API reference.
+  dispose() {
+    controller.dispose();
+    super.dispose();
+  }
+}
+```
+### Special thanks to react native vector ICONS library and its authors