我有一系列的行星对象，并且我正在尝试创建一个函数，该函数可以是其中一个行星，并且仅渲染一个行星。
我试图创建一个用于从数组中筛选出行星的函数，但是我没有成功。
sortPlanet() {
const planet = this.state.sort((a, b) => a.index > b.index )
}
然后我试图在地图前输入一个类型
const { data } = this.state
const planets = data
.sort((a, b) => a.index > b.index )
.map((planet, index) => {
return (<div key={index} className="app-container">
<div>
<h1>{planet.name}</h1>
</div>
<div className="about-container">
<span>Population: {planet.population}</span>
<span>Climate: {planet.climate}</span>
<span>Terrain: {planet.terrain}</span>
<br />
<span>{planet.films.length}</span>
</div>
</div>)
})
import './App.css';
class App extends Component {
state = {
data: [],
}
componentDidMount() {
const url = 'https://swapi.co/api/planets/'
fetch(url)
.then(response => response.json())
.then(response => {
this.setState({
data: response.results,
})
})
}
render() {
const { data } = this.state
const planets = data
.map((planet, index) => {
return (<div key={index} className="app-container">
<div>
<h1>{planet.name}</h1>
</div>
<div className="about-container">
<span>Population: {planet.population}</span>
<span>Climate: {planet.climate}</span>
<span>Terrain: {planet.terrain}</span>
<br />
<span>{planet.films.length}</span>
</div>
</div>)
})
console.log(planets)
return (
<div className="App">
{planets}
<button>Next</button>
</div>
)
}
}
export default App;
我的目标是仅对一个星球进行分类，每当我单击“下一步”按钮时，都会调用该函数随机搜索另一个星球。
编辑： 添加示例数据
[
{
"name": "Alderaan",
"rotation_period": "24",
"orbital_period": "364",
"diameter": "12500",
"climate": "temperate",
"gravity": "1 standard",
"terrain": "grasslands, mountains",
"surface_water": "40",
"population": "2000000000",
"residents": [
"https://swapi.co/api/people/5/",
"https://swapi.co/api/people/68/",
"https://swapi.co/api/people/81/"
],
"films": [
"https://swapi.co/api/films/6/",
"https://swapi.co/api/films/1/"
],
"created": "2014-12-10T11:35:48.479000Z",
"edited": "2014-12-20T20:58:18.420000Z",
"url": "https://swapi.co/api/planets/2/"
},
{
"name": "Yavin IV",
"rotation_period": "24",
"orbital_period": "4818",
"diameter": "10200",
"climate": "temperate, tropical",
"gravity": "1 standard",
"terrain": "jungle, rainforests",
"surface_water": "8",
"population": "1000",
"residents": [],
"films": [
"https://swapi.co/api/films/1/"
],
"created": "2014-12-10T11:37:19.144000Z",
"edited": "2014-12-20T20:58:18.421000Z",
"url": "https://swapi.co/api/planets/3/"
},
{
"name": "Hoth",
"rotation_period": "23",
"orbital_period": "549",
"diameter": "7200",
"climate": "frozen",
"gravity": "1.1 standard",
"terrain": "tundra, ice caves, mountain ranges",
"surface_water": "100",
"population": "unknown",
"residents": [],
"films": [
"https://swapi.co/api/films/2/"
],
"created": "2014-12-10T11:39:13.934000Z",
"edited": "2014-12-20T20:58:18.423000Z",
"url": "https://swapi.co/api/planets/4/"
}
]
答案 0 :(得分：3)
也许我误会了你想做什么。似乎您不需要对它们进行排序。
如果您想随机使用行星
Math.floor(Math.random() * this.state.data.length)
您可以在状态中使用2个数组，而不仅仅是一个。一种是从中获取随机行星的阵列，另一种是您在其中设置顺序的行星。
如果要渲染一个星球，则不应该绘制所有星球。我会将您的状态更改为
state = {
data: [],
chosenPlanet: 0
}
并使用
渲染地球const index = this.state.chosenPlanet;
const planet= this.state.data[index]
const renderPlanet =
(<div className="app-container">
<div>
<h1>{planet.name}</h1>
</div>
<div className="about-container">
<span>Population: {planet.population}</span>
<span>Climate: {planet.climate}</span>
<span>Terrain: {planet.terrain}</span>
<br />
<span>{planet.films.length}</span>
</div>
</div>)
答案 1 :(得分：0)
因此，到目前为止，您只需花5分钟即可快速获取您提供的代码。我自由地根据您的文本重构某些内容，以使您更符合目标。如果您希望一次仅渲染1个行星，则无需担心渲染整个列表并将其隐藏。使用反应state管理来渲染第1颗行星，当状态改变时，组件将重新渲染并为您提供新的行星。
现在这个：
sortPlanet() {
const planet = this.state.sort((a, b) => a.index > b.index )
}
此代码无效。默认情况下，Planet作为对象没有索引。我相信您正在尝试访问数组内部的索引。数组的排序顺序应该无关紧要。您只需要从阵列中随机挑选一颗行星即可。
class App extends Component {
constructor(props) {
super(props);
const url = 'https://swapi.co/api/planets/';
state = {
randomPlanet: 0,
planets: fetch(url) // make your fetch here, it is cleaner and better
.then((response) => response.json())
.then((response) => {
return response.sort((a, b) => a.name - b.name);
}),
};
}
// you dont want to render the entire list, you just want to render one at a time randomly
renderPlanet() {
const { planets, randomPlanet } = this.state;
const planet = planets[randomPlanet];
return (
<div key={index} className='app-container'>
<div>
<h1>{planet.name}</h1>
</div>
<div className='about-container'>
<span>Population: {planet.population}</span>
<span>Climate: {planet.climate}</span>
<span>Terrain: {planet.terrain}</span>
<br />
<span>{planet.films.length}</span>
</div>
</div>
);
}
// get a random number between 0 and the numbe of planets, use that to access the index of your planets array
getRandomArbitrary(min, max) {
return Math.random() * (max - min) + min;
}
// update the current randon planet in state to get your next random planet
getNextPlanet = () => {
this.setState(({planets}) => ({
randomPlanet: getRandomArbitrary(0, planets.length),
}));
};
render() {
return (
<div className='App'>
{this.renderPlanet()}
<button onPress={this.getNextPlanet}>Next</button>
</div>
);
}
}
export default App;