[英]How do I use a custom ReactJs component inside my JSX file from ReactJs.Net
[英]How do i use my incremented value inside inside an other component
For school i need to make an react app, it is my first time using, html, css, javascript and react and now i am stuck on part where i have to post the data to an API. 我的职责是创建一个页面,人们可以在其中 select 吃喝玩乐以及按下 oke。 数据已发送。
我创建了一个选择器
import React, { Component } from "react";
export default class Selector extends Component {
state = {
value: this.props.selector.value,
};
handleIncrement = () => {
this.setState({ value: this.state.value + 1 });
console.log(this.state.value);
};
handleDecrement = () => {
this.setState({ value: this.state.value - 1 });
};
render() {
return (
<div>
{this.props.children}
<span>{this.state.value}</span>
<button
onClick={this.handleIncrement}
className="btn btn-secondary btn-sm m-2"
>
+
</button>
<button
onClick={this.handleDecrement}
className="btn btn-secondary btn-sm m-2"
>
-
</button>
<button
onClick={() =>
this.setState({
value: 0,
})
}
className="btn btn-danger btn-sm m-2"
>
Reset
</button>
</div>
);
}
}
从一个选择器我做了多个选择器
import React, { Component } from "react";
import Selector from "./selector";
import axios from "axios";
export default class Selectors extends Component {
state = {
skittleSelectors: [
{ id: 1, value: 0, color: "Green", availability: 0 },
{ id: 2, value: 0, color: "Red", availability: 0 },
{ id: 3, value: 0, color: "Yellow", availability: 0 },
{ id: 4, value: 0, color: "Purple", availability: 0 },
{ id: 5, value: 0, color: "Orange", availability: 0 },
],
};
postData(){
const greenSelector = this.state.skittleSelectors.findIndex(
(element) => element.color === "Green"
);
let greenValue = this.state.skittleSelectors[greenSelector].value;
console.log(greenValue);
};
render() {
return (
<div>
<button onClick={this.postData}>POSTDATA</button>
{this.state.skittleSelectors.map((selector) => (
<Selector
key={selector.id}
selector={selector}
onReset={this.handleReset}
>
<p>{selector.color}:</p>
<p>amount availible: {selector.availability}</p>
</Selector>
))}
</div>
);
}
}
现在我的问题
当我记录单个选择器的 handleIncrement() 中的值时,它会正确显示在控制台中。 但我想在选择器页面中使用该数据。 但是当我尝试在那里记录它时,它只是说 0 因为初始值。
我该如何解决这个问题。 我曾尝试使用 Selector.jsx 中的帖子,但我认为那不正确,我仍然无法让它工作。 我通过使用 componentDidMount() 和 componendDitUpdate() 在这里和那里进行了一些尝试,但没有成功。
那么如何使用我的 Selectors 文件中的 postData 方法中的更新声明。 我希望你们能在这里帮助我,1天后我完全卡住了。
先感谢您。
我已经修复了你的代码。 实际上,您需要将更改的值从Selector
传递给Selectors
,这就是我使用onChangedValue
道具所做的。 此外,当您使用当前state
更改state
时,我已经更改了setState
您应该使用prevState
选择器组件
import React, {Component} from "react";
import axios from "axios";
import Selector from "./Selector";
export default class Selectors extends Component {
state = {
skittleSelectors: [
{id: 1, value: 0, color: "Green", availability: 0},
{id: 2, value: 0, color: "Red", availability: 0},
{id: 3, value: 0, color: "Yellow", availability: 0},
{id: 4, value: 0, color: "Purple", availability: 0},
{id: 5, value: 0, color: "Orange", availability: 0},
],
};
postData = () => {
const greenSelector = this.state.skittleSelectors.findIndex(
(element) => element.color === "Green"
);
let greenValue = this.state.skittleSelectors[greenSelector].value;
console.log(greenValue);
};
onChangedValue = (selector, value) => {
this.setState(prevState => {
let currentItem = this.state.skittleSelectors.find(s => s.id === selector.id);
currentItem.value = value;
return{ skittleSelectors: [...this.state.skittleSelectors] }
}, console.log(this.state.skittleSelectors, 'skittleSelectors'));
};
render() {
return (
<div>
<button onClick={this.postData}>POSTDATA</button>
{this.state.skittleSelectors.map((selector) => (
<Selector
key={selector.id}
selector={selector}
onReset={this.handleReset}
onChangedValue={this.onChangedValue}
>
<p>{selector.color}:</p>
<p>amount availible: {selector.availability}</p>
</Selector>
))}
</div>
);
}
}
选择器组件
import React, {Component} from "react";
export default class Selector extends Component {
state = {
value: this.props.selector.value,
};
handleIncrement = () => {
this.setState(prevState => {
return {value: prevState.value + 1}
}, () => this.props.onChangedValue(this.props.selector, this.state.value));
};
handleDecrement = () => {
this.setState(prevState => {
return {value: prevState.value - 1}
}, () => this.props.onChangedValue(this.props.selector, this.state.value));
};
render() {
return (
<div>
{this.props.children}
<span>{this.state.value}</span>
<button
onClick={this.handleIncrement}
className="btn btn-secondary btn-sm m-2"
>
+
</button>
<button
onClick={this.handleDecrement}
className="btn btn-secondary btn-sm m-2"
>
-
</button>
<button
onClick={() =>
this.setState({
value: 0,
})
}
className="btn btn-danger btn-sm m-2"
>
Reset
</button>
</div>
);
}
}
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