Question

我试图通过编写类似小型体育名册的UI来学习React概念，特别是re：状态和动态UI。我已经包含了以下代码，整个app + visual位于http://codepen.io/emkk/pen/dGYXJO。这个应用程序基本上是从我之前定义的一系列玩家对象中创建玩家卡片。

我想在点击按钮时实现播放器卡的排序。我创建了一个<Sort/>组件，用于呈现所述按钮。我附上了事件监听器，但不知道如何在我的<Roster/>组件中反映出来。我已经使用this.state尝试了许多不同的方法，但似乎无法实现此功能。所以，任何有关实施排序或一般建议的帮助都会受到很多关注！

class ProfileCard extends React.Component {
  render() {
    return (
      <section className="profile-card">
        <figure>
          <img src={this.props.player.picURL} alt={this.props.player.Name}></img>
          <article>
            <ul>
              <li>{this.props.player.Name}</li>
              <li>{this.props.player.position}, #{this.props.player.number}</li>
              <li>{this.props.player.Club}</li>
              <li>{this.props.player.Height} ({this.props.player.Meters} m)</li>
              <li>{this.props.player.Age} years old</li>
            </ul>
          </article>
        </figure>
      </section>
    );
  }
}

class Roster extends React.Component {
  render() {

    // Store sorted version of data
    // Where I'd implement selected sorting
    var sorted = this.props.players.sort();

    /*
    * Create player cards from JSON collection
    */
    var cards = [];
    sorted.forEach(function(player) {
      if (player.year > 2000) {
        cards.push(<ProfileCard player={player} />);
      }
    });

    return (<div>{cards}</div>);
  }
}

class Sort extends React.Component {
  render() {
    return (
      <div className="sort-section">
        <h1>Sort by</h1>
        <div className="pill" id='age'>Age</div>
        <div className="pill" id='Meters'>Height</div>
        <div className="pill" id='Name'>Name</div>
      </div>
    )
  }
}

class SortablePlayerTable extends React.Component {

  render() {
    /*
    * Prefix some interestings stats
    * before roster
    */
    var ages = [], heights = [];

    this.props.players.forEach(function(player) {
      if (player.year > 2000) {
        ages.push(player.Age);
        heights.push(player.Meters);
      }
    });
    var avgAge = (ages.reduce( (a, b) => a + b) / 12).toPrecision(3);
    var avgHeights = (heights.reduce( (a, b) => a + b) / 12).toPrecision(3);

    // Return page with stats data and Roster
    return (
      <div>
        <h1>2012 Olympic Men's Basketball Team</h1>
        <h2>Average Age: {avgAge} years old</h2>
        <h2>Average Height: 6 ft 7 in ({avgHeights} m)</h2>
        <Sort/>
        <Roster 
                players={this.props.players} 
        />
      </div>
    );
  }
};

React.render(
  <SortablePlayerTable players={PLAYERS} />,
  document.getElementById('container')
);

解决方案：

让我感到沮丧的另一件事是，我失去了对this.setState的访问权限，导致this.setState is a not a function错误。使用ES6箭头函数来词法绑定this我的处理函数虽然救了我。

class ProfileCard extends React.Component {
  render() {
    return (
      <section className="profile-card">
        <figure>
          <img src={this.props.player.picURL} alt={this.props.player.Name}></img>
          <article>
            <ul>
              <li>{this.props.player.Name}</li>
              <li>{this.props.player.position}, #{this.props.player.number}</li>
              <li>{this.props.player.Club}</li>
              <li>{this.props.player.Height} ({this.props.player.Meters} m)</li>
              <li>{this.props.player.Age} years old</li>
            </ul>
          </article>
        </figure>
      </section>
    );
  }
}

class Roster extends React.Component {
  render() {
    // Create player cards from sorted, dynamic JSON collection
    var cards = [];
    this.props.players.forEach(function(player) {
      if (player.year > 2000) {
        cards.push(<ProfileCard player={player} />);
      }
    });

    return (<div>{cards}</div>);
  }
}

class Sort extends React.Component {
  sortRoster(field){
    var players = this.props.players;
    this.props.sortRosterStateBy(field, players);
  }
  render() {
    return (
      <div className="sort-section">
        <h1>Sort by</h1>
        <div className="pill" onClick={this.sortRoster.bind(this,'Age')} >Age</div>
        <div className="pill" onClick={this.sortRoster.bind(this,'Meters')} >Height</div>
        <div className="pill" onClick={this.sortRoster.bind(this,'Name')} >Name</div>
        <div className="pill" onClick={this.sortRoster.bind(this,'position')} >Position</div>
        <div className="pill" onClick={this.sortRoster.bind(this,'number')} >Number</div>
        <div className="pill" onClick={this.sortRoster.bind(this,'Club')} >Club</div>
      </div>
    )
  }
}

class SortablePlayerTable extends React.Component {
  state = {
   'players': this.props.players // default state
  }

  sortRosterStateBy = (field, players) => {
    // Sorting ...
    var sortedPlayers = players.sort( (a, b) => {
      if (a[field] > b[field]) {
        return 1;
      }
      if (a[field] < b[field]) {
        return -1;
      }
      return 0;
    });

    // Then call setState
    this.setState({'players': sortedPlayers});
  }

  render() {
    // Prefix some interestings stats before roster
    var ages = [], heights = [];
    this.props.players.forEach(function(player) {
      if (player.year > 2000) {
        ages.push(player.Age);
        heights.push(player.Meters);
      }
    });
    var avgAge = (ages.reduce( (a, b) => a + b) / 12).toPrecision(3);
    var avgHeight = (heights.reduce( (a, b) => a + b) / 12).toPrecision(3);

    // Return page with stats data and Roster
    return (
      <div>
        <h1>2012 Olympic Men's Basketball Team</h1>
        <h2>Average Age: {avgAge} years old</h2>
        <h2>Average Height: 6 ft 7 in ({avgHeight} m)</h2>
        <Sort players={this.props.players} sortRosterStateBy={this.sortRosterStateBy}/>
        <Roster players={this.state.players}/>
      </div>
    );
  }
};

ReactDOM.render(
  <SortablePlayerTable players={PLAYERS} />,
  document.getElementById('container')
);

Answer 1

将一个函数附加到<div/>中的每个<Sort/>点击它所谓的父函数this.props.sortBy()

class Sort extends React.Component {
  sort(field){
    this.props.sortBy(field);
  }
  render() {
    return (
      <div className="sort-section">
        <h1>Sort by</h1>
        <div className="pill" id='age' onClick=this.sort.bind(this,'age')>Age</div>
        <div className="pill" id='Meters' onClick=this.sort.bind(this,'height')>Height</div>
        <div className="pill" id='Name' onClick=this.sort.bind(this,'name')>Name</div>
      </div>
    )
  }
}

将此父作品sortBy从props组件传递为<SortablePlayerTable/>。

class SortablePlayerTable extends React.Component {
  state = {
   players: [] // default state
  }
  sortBy(field){
    // Your sorting algorithm here
    // it should push the sorted value by field in array called sortedPlayers 
    // Then call setState
    this.setState({
      players: sortedPlayers
    });
  }
  render() {
    // calculate stats
    return (
      <div>
        {/* some JSX */}
        <Sort sortBy={sortBy}/>
        <Roster 
                players={this.state.players} 
        />
      </div>
    );
  }
};

现在，已排序的数组将<Roster/>组件作为this.props.players。直接渲染数组，而不在<Roster/>组件中应用任何排序。

React.js - 实现组件的排序

1 个答案: