我正在 useEffect 钩子中调度一个操作来获取数据，然后使用来自 redux 存储的数据更新状态。当页面第一次加载时，我得到了正确的数据，但在刷新浏览器时我得到了未定义的值。
React.useEffect(() => {
dispatch(getSingleCoin(props.match.params.id))
setName(coinDetail.name)
setSymbol(coinDetail.symbol)
setLogourl(coinDetail.logo)
setPrice(coinDetail.price)
setLaunchDate(coinDetail.launchDate)
setWebsiteUrl(coinDetail.websiteUrl)
setNetwork(coinDetail.chain)
setAddress(coinDetail.address)
setTwitterUrl(coinDetail.twitter)
setTelegramUrl(coinDetail.telegram)
setRedditUrl(coinDetail.reddit)
setYoutubeUrl(coinDetail.youtube)
setCoinDescription(coinDetail.description)
setMarketCap(coinDetail.marketCap)
}
}, [coinDetail,dispatch, props.match.params.id])
const handleSubmit = (e) => {
e.preventDefault()
const coin = {}
coin.name = name
coin.symbol = symbol
coin.logo = logourl
coin.price = price
coin.launchDate = launchDate
coin.websiteUrl = websiteUrl
coin.chain = network
coin.address = address
coin.twitter = twitterUrl
coin.telegram = telegramUrl
coin.reddit = redditUrl
coin.youtube = youtube
coin.description = coinDescription
coin.marketCap = marketCap
coin._id = props.match.params.id
dispatch(updateCoin(coin))
}
return (
<div className="container add-coin-wapper mt-4">
{loading && coinDetail === undefined ? (
<div>...Loading</div>
) : error ? (
<div>{error}</div>
) : (
<div className="card ">
<div className="card-header">
<div className="approve-header">
<div
className="approve-back"
onClick={() => props.history.push('/Admin/coinlist')}
>
<ArrowBackIosIcon />
<div>Back to Coin listing</div>
</div>
</div>
</div>
<div className="card-body">
{/* here */}
<>
<div>
<h3>Edit Coin</h3>
</div>
<form onSubmit={handleSubmit}>
<div className="row">
<div className="col-sm-12 col-md-6 col-lg-6">
<h5>Coin informations</h5>
<div className="form-group">
<label htmlFor="name">name</label>
<input
type="text"
className="form-control"
id="name"
name="name"
placeholder="Bitcoin"
required
onChange={(e) => setName(e.target.value)}
value={name}
/>
</div>
<div className="form-group">
<label htmlFor="symbol">symbol</label>
<input
type="text"
className="form-control"
id="symbol"
name="symbol"
placeholder="Enter symbol"
onChange={(e) => setSymbol(e.target.value)}
required
value={symbol}
/>
</div>
<div className="form-group">
<label htmlFor="logo">Logo url</label>
<input
type="text"
className="form-control"
id="url"
name="logourl"
placeholder="https://clod.com/logo"
onChange={(e) => setLogourl(e.target.value)}
value={logourl}
/>
</div>
<div className="form-group">
<label htmlFor="description">Coin Description</label>
<textarea
className="form-control"
id="exampleFormControlTextarea1"
rows="3"
onChange={(e) => setCoinDescription(e.target.value)}
placeholder="Describe your coin appropriately to show attractiveness"
value={coinDescription}
></textarea>
</div>
<div className="form-group">
<label htmlFor="price">price</label>
<div className="input-group mb-2">
<div className="input-group-prepend">
<div className="input-group-text">$</div>
</div>
<input
type="number"
className="form-control"
id="marketcap"
placeholder="0.00085"
step="any"
min="0"
onChange={(e) => setPrice(e.target.value)}
value={price}
/>
</div>
</div>
<div className="form-group">
<label htmlFor="marketcap">Market cap</label>
<div className="input-group mb-2">
<div className="input-group-prepend">
<div className="input-group-text">$</div>
</div>
<input
type="number"
className="form-control"
id="marketcap"
step="any"
placeholder="0.00085"
min="0"
onChange={(e) => setMarketCap(e.target.value)}
value={marketCap}
/>
</div>
</div>
<div className="form-group">
<label htmlFor="launchdate">Launch date</label>
<div
className="input-group date"
data-provide="datepicker"
>
<input
type="date"
className="form-control"
onChange={(e) => setLaunchDate(e.target.value)}
value={moment(launchDate).format('YYYY-MM-DD')}
/>
<div className="input-group-addon">
<span className="glyphicon glyphicon-th"></span>
</div>
</div>
</div>
</div>
<div className="col-sm-12 col-md-6 col-lg-6">
<h5>Coin market</h5>
<div className="form-group">
<label htmlFor="network">Network/Chain</label>
<select
className="form-control"
id="network"
onChange={(e) => setNetwork(e.target.value)}
value={network}
>
<option value="BSC">Binance Smart Chain (BSC)</option>
<option value="ETH">Ethereum (ETH)</option>
<option value="SOL">Solona (SOL)</option>
</select>
</div>
<div className="form-group">
<label htmlFor="contract">Contract Adress</label>
<input
type="text"
className="form-control"
id="contract"
name="contract"
placeholder="xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
onChange={(e) => setAddress(e.target.value)}
required
value={address}
/>
</div>
<h5>Coin links</h5>
<div className="form-group">
<label htmlFor="weburl">Website url</label>
<div className="input-group mb-2">
<div className="input-group-prepend">
<div className="input-group-text">
<LanguageIcon />
</div>
</div>
<input
type="text"
className="form-control"
id="web"
placeholder="https://www.coinx.com"
onChange={(e) => setWebsiteUrl(e.target.value)}
required
value={websiteUrl}
/>
</div>
</div>
<div className="form-group">
<label htmlFor="twitter">Twitter</label>
<div className="input-group mb-2">
<div className="input-group-prepend">
<div className="input-group-text">
<TwitterIcon />
</div>
</div>
<input
type="text"
className="form-control"
id="twitter"
placeholder="https://twitter.com/"
onChange={(e) => setTwitterUrl(e.target.value)}
value={twitterUrl}
/>
</div>
</div>
<div className="form-group">
<label htmlFor="telegram">Telegram</label>
<div className="input-group mb-2">
<div className="input-group-prepend">
<div className="input-group-text">
<TelegramIcon />
</div>
</div>
<input
type="text"
className="form-control"
id="telegram"
placeholder="https://t.me/"
onChange={(e) => setTelegramUrl(e.target.value)}
value={telegramUrl}
/>
</div>
</div>
<div className="form-group">
<label htmlFor="youtube">YouTube</label>
<div className="input-group mb-2">
<div className="input-group-prepend">
<div className="input-group-text">
<YouTubeIcon />
</div>
</div>
<input
type="text"
className="form-control"
id="youtube"
placeholder="https://www.youtube.com/watch?v="
onChange={(e) => setYoutubeUrl(e.target.value)}
value={youtube}
/>
</div>
</div>
<div className="form-group">
<label htmlFor="reddit">Reddit</label>
<div className="input-group mb-2">
<div className="input-group-prepend">
<div className="input-group-text">
<RedditIcon />
</div>
</div>
<input
type="text"
className="form-control"
id="reddit"
placeholder="https://www.reddit.com"
onChange={(e) => setRedditUrl(e.target.value)}
value={redditUrl}
/>
</div>
</div>
<button type="submit" className="btn" disabled={loading}>
update
</button>
</div>
</div>
</form>
</>
{/* here */}
</div>
{/* here */}
</div>
)}
</div>
状态数据应该显示在表单输入元素中。在获取数据并将加载设置为 false 之前，我渲染了一个具有加载状态的 div。