[英]React.js Increment and Decrement counter not mapping correctly
讓我以為我正在學習React的過程中,對此我還是很環保的。
我將提供代碼的必要部分:
我建立了一個帶有遞增和遞減按鈕的計數器,這些按鈕可以通過狀態使用,在我引入並對其進行數組和映射之前,它們工作得很好。 然后事情開始崩潰。 我知道我的代碼是錯誤的,我知道有什么不對勁,但是我對尋找的東西一無所知。
在我的counting.js
我有:
const players = [
{
name: "Jon Smith",
score: 10,
id: 1,
},
{
name: "Jon Doe",
score: 40,
id: 2,
},
{
name: "John Ham",
score: 30,
id: 3,
},
];
我在這里映射的:
class Counting extends React.Component {
constructor(props) {
super(props);
this.state = {
count: 0,
nameof: 'Full Name',
}
this.incrementCount = this.incrementCount.bind(this)
this.decrementCount = this.decrementCount.bind(this)
}
incrementCount(e) {
this.setState({
count: (this.state.count + 1),
})
}
decrementCount(e) {
this.setState({
count: (this.state.count - 1),
})
}
render() {
const listPlayers = players.map((players) =>
<Counter
key={players.id}
incrementCount={this.incrementCount}
decrementCount={this.decrementCount}
nameof={players.name}
count={players.score}
/>
);
return (
<div className="wrap">
<Titles header="Counter" subhead="A setState() project" subtitle="this will change" />
<h3>This doesn't work correctly</h3>
<ul>{listPlayers}</ul>
<ScoreList>
<h3> works</h3>
<li>
<Counter
incrementCount={this.incrementCount}
decrementCount={this.decrementCount}
nameof={this.state.nameof}
count={this.state.count}
/>
</li>
<li>
<Counter
incrementCount={this.incrementCount}
decrementCount={this.decrementCount}
nameof={this.state.nameof}
count={this.state.count}
/>
</li>
</ScoreList>
</div>
)
}
}
我已經導入了我的Counter.js
,其中包括:
class Counter extends Component {
render() {
const { count } = this.props
const { decrementCount } = this.props
const { incrementCount } = this.props
const { nameof } = this.props
return (
<div>
<CountCell>
<Row style={{alignItems: 'center'}}>
<Col>
<CountButton
onClick={incrementCount}>
<Icon
name="icon" className="fa fa-plus score-icon"
/>
</CountButton>
</Col>
<Col >
<ScoreName>{nameof}</ScoreName>
</Col>
<Col >
<Score>{count}</Score>
</Col>
<Col>
<CountButton
onClick={decrementCount}>
<Icon
name="icon" className="fa fa-minus score-icon"
/>
</CountButton>
</Col>
</Row>
</CountCell>
</div>
)
}
}
因此,遞增和遞減按鈕僅在全局范圍內起作用,並且僅適用於我的靜態<li>
,不適用於從數組生成的按鈕。 如果我有任何意義,如何將inc / dec按鈕分別映射到每個<li>
而不是全局映射?
謝謝!
您還需要保持狀態為對象數組,每個對象存儲一個對應用戶的數據
class Counting extends React.Component {
constructor(props) {
super(props);
this.state = {
countInfo: []
}
this.incrementCount = this.incrementCount.bind(this)
this.decrementCount = this.decrementCount.bind(this)
}
incrementCount(index) {
var countInfo = [...this.state.countInfo];
if(countInfo[index]) {
countInfo[index].count = countInfo[index].count + 1
countInfo[index].nameOf = players[index].name
}
else {
countInfo[index] = {count: 1, nameOf: players[index].name}
}
this.setState({
countInfo
})
}
decrementCount(index) {
var countInfo = [...this.state.countInfo];
if(countInfo[index]) {
countInfo[index].count = countInfo[index].count - 1
countInfo[index].nameOf = players[index].name
}
else {
countInfo[index] = {count: -1, nameOf: players[index].name}
}
this.setState({
countInfo
})
}
render() {
const listPlayers = players.map((players, index) =>
<Counter
key={players.id}
incrementCount={() => this.incrementCount(index)}
decrementCount={() => this.decrementCount(index)}
nameof={players.name}
count={players.score}
/>
);
return (
<div className="wrap">
<Titles header="Counter" subhead="A setState() project" subtitle="this will change" />
<h3>This doesn't work correctly</h3>
<ul>{listPlayers}</ul>
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.