ReactJS動畫 - ReactJS教學

在本章中，我們將學習React如何使用動畫元素。

第1步 - 安裝React CSS轉換組

這是React插件，用於創建基本的CSS轉換和動畫。從命令提示符窗口中安裝它 -

F:\worksp\reactjs\reactApp> npm install react-addons-css-transition-group

第2步 - 添加一個CSS檔

在專案根目錄裏面創建一個新的檔夾：css，並在檔夾中創建一個檔：style.css 。為了能夠在應用程式中使用它，需要將它添加到index.html中的head元素中。如下檔(index.html)代碼所示 -

<!DOCTYPE html>
<html lang = "en">

   <head>
      <meta charset = "UTF-8">
      <title>React動畫示例</title>
      <link rel = "stylesheet" type = "text/css" href = "css/style.css">
   </head>

   <body>
      <div id = "app"></div>
      <script type = "text/javascript" src = "index.js"></script>
   </body>

</html>

第3步 - 出現動畫

創建一個基本的React組件。 ReactCSSTransitionGroup元素將被用作想要動畫的組件的包裝。它將使用transitionAppear和transitionAppearTimeout，而transitionEnter和transitionLeave是false。

檔：App.jsx -

import React from 'react';
var ReactCSSTransitionGroup = require('react-addons-css-transition-group');

class App extends React.Component {
   render() {
      return (
         <div>
            <ReactCSSTransitionGroup transitionName = "example"
               transitionAppear = {true} transitionAppearTimeout = {500}
               transitionEnter = {false} transitionLeave = {false}>
               <h1>My Element...</h1>
            </ReactCSSTransitionGroup>
         </div>
      );
   }
}
export default App;

檔：main.js -

import React from 'react'
import ReactDOM from 'react-dom';
import App from './App.jsx';

ReactDOM.render(<App />, document.getElementById('app'));

CSS動畫非常簡單。檔：css/style.css -

.example-appear {
   opacity: 0.01;
}
.example-appear.example-appear-active {
   opacity: 1;
   transition: opacity 500ms ease-in;
}

當啟動應用程式，元素將淡入。

第4步 - 輸入和離開動畫

當想要添加或刪除列表中的元素時，可以使用輸入和離開動畫。

檔：App.jsx -

import React from 'react';
var ReactCSSTransitionGroup = require('react-addons-css-transition-group');

class App extends React.Component {
   constructor(props) {
      super(props);

      this.state = {
         items: ['Item 1...', 'Item 2...', 'Item 3...', 'Item 4...']
      }
      this.handleAdd = this.handleAdd.bind(this);
   };
   handleAdd() {
      var newItems = this.state.items.concat([prompt('Create New Item')]);
      this.setState({items: newItems});
   }
   handleRemove(i) {
      var newItems = this.state.items.slice();
      newItems.splice(i, 1);
      this.setState({items: newItems});
   }
   render() {
      var items = this.state.items.map(function(item, i) {
         return (
            <div key = {item} onClick = {this.handleRemove.bind(this, i)}>
               {item}
            </div>
         );
      }.bind(this));

      return (
         <div>
            <button onClick = {this.handleAdd}>Add Item</button>

            <ReactCSSTransitionGroup transitionName = "example"
               transitionEnterTimeout = {500} transitionLeaveTimeout = {500}>
               {items}
            </ReactCSSTransitionGroup>
         </div>
      );
   }
}
export default App;

檔：main.js -

import React from 'react'
import ReactDOM from 'react-dom';
import App from './App.jsx';

ReactDOM.render(<App />, document.getElementById('app'));

檔：css/style.css -

.example-enter {
   opacity: 0.01;
}
.example-enter.example-enter-active {
   opacity: 1;
   transition: opacity 500ms ease-in;
}
.example-leave {
   opacity: 1;
}
.example-leave.example-leave-active {
   opacity: 0.01;
   transition: opacity 500ms ease-in;
}

當啟動應用程式，然後點擊添加專案按鈕，會出現提示。