这里有一个代码框向您展示如何重置项目：https://codesandbox.io/s/romantic-heisenberg-93qi7
我还给你留下了一条关于如何让它与你的 API 数据一起工作的注释，请参阅onChangeText() 中的评论
问题在于输入不受您推断的状态控制。我们应该为您的 API 中的每个项目创建一个更新的对象，并为其提供一个 value 属性。
index.js
import React from "react";
import ReactDOM from "react-dom";
import Cart from "./Cart";
import "./styles.css";
class App extends React.Component {
constructor(props) {
super(props);
this.state = {
Items: [],
itemvalues: [{}]
};
this.onChangeText = this.onChangeText.bind(this);
this.getItems = this.getItems.bind(this);
this.handleReset = this.handleReset.bind(this);
this.handleSubmit = this.handleSubmit.bind(this);
this.findFieldIndex = this.findFieldIndex.bind(this);
this.trimText = this.trimText.bind(this);
}
getItems = () => {
/*if the data is coming from an API, store it in an array then .map() over it.
we can add a value prop to the object like:
so you can do something like:
const newItems = [...apiData].map((item) => {
return {
...item,
value: ""
}
})
this.setState({
Items: newItems
})
*/
this.setState({
Items: [
{
name: "item1",
description: "item1",
group: "groupA",
dtype: "str",
value: ""
},
{
name: "item2",
description: "item2",
group: "groupA",
dtype: "str",
value: ""
},
{
name: "item3",
description: "item3",
group: "groupB",
dtype: "str",
value: ""
},
{
name: "item4",
description: "item4",
group: "groupB",
dtype: "str",
value: ""
}
]
});
};
onChangeText = e => {
const updatedItems = [...this.state.Items].map(item => {
if (item.name === e.target.name) {
return {
...item,
value: e.target.value
};
} else {
return item;
}
});
const updatedItemValues = [...updatedItems].reduce((obj, curr) => {
if (!obj[curr.group]) {
obj[curr.group] = [];
}
obj[curr.group] = [...obj[curr.group], { [curr.name]: curr.value }];
return obj;
}, {});
this.setState({
...this.state,
Items: updatedItems,
itemvalues: updatedItemValues
});
};
findFieldIndex = (array, name) => {
return array.findIndex(item => item[name] !== undefined);
};
trimText(str) {
return str.trim();
}
handleReset = () => {
const resetedItems = [...this.state.Items].map(item => {
return {
...item,
value: ""
};
});
this.setState(
{
...this.state,
Items: resetedItems,
itemvalues: []
},
() => console.log(this.state)
);
};
handleSubmit = () => {
console.log(this.state.itemvalues);
};
render() {
return (
<div>
{
<Cart
Items={this.state.Items}
getItems={this.getItems}
handleSubmit={this.handleSubmit}
handleReset={this.handleReset}
onChangeText={this.onChangeText}
/>
}
</div>
);
}
}
购物车.js
import React, { useEffect } from "react";
import Form from "./Form";
const Cart = props => {
useEffect(() => {
props.getItems(props.Items);
}, []);
return (
<div>
<Form Items={props.Items} onChangeText={props.onChangeText} />
<button onClick={props.handleSubmit}>Submit</button>
<button onClick={props.handleReset}>Reset</button>
</div>
);
};
export default Cart;
Cart 组件可以基本保持不变，我们不需要将 props.items 传递给 useEffect() 依赖项。
Form.js
import React from "react";
const Form = props => {
return (
<div>
{props.Items.map(item => {
return (
<input
name={item.name}
placeholder={item.description}
data-type={item.dtype}
data-group={item.group}
onChange={e => props.onChangeText(e)}
value={item.value}
/>
);
})}
</div>
);
};
export default Form;
现在在Form 组件中，我们为每个输入提供一个值道具，该道具连接到我们最上面的父组件状态的项目。
这就是重置值所需的全部内容。