我正在尝试通过编写类似于体育名册的小型UI来学习React概念,特别是re：状态和动态UI.我已经包含了下面的代码,整个应用程序视觉是在
http://codepen.io/emkk/pen/dGYXJO.这个应用程序基本上从我之前定义的一系列玩家对象创建玩家卡.
我想在点击按钮时实现播放器卡的排序.我创建了一个< Sort />呈现所述按钮的组件.我会附加事件监听器,但不知道如何在我的< Roster />中反映出来.零件.我已经用this.state尝试了很多不同的方法,但似乎无法让它工作.所以,任何有关实施分类或一般建议的帮助都会受到很大的帮助！
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：
另一件让我感到困惑的事情就是我失去了对this.setState的访问权限,不断得到一个this.setState不是一个函数错误.使用ES6箭头函数来词法绑定这个为我的处理函数救出了我.
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')
);
解决方法
将函数附加到每个< div /> in< Sort />点击它调用父函数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>
)
}
}
将此父函数sortBy作为道具从< SortablePlayerTable />中传递出来零件.
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,排序的数组将可用于您的< Roster />组件为this.props.players.直接渲染数组而不在其中应用任何排序< Roster />零件.
