在React ES6中，为什么输入字段在键入字符后失去焦点? [英] In React ES6, why does the input field lose focus after typing a character?

问题描述

在下面的组件中，输入字段在键入字符后会失去焦点.在使用Chrome浏览器的Inspector时，看起来在重新渲染整个表单，而不仅仅是在输入时重新输入了输入字段的value属性.

In my component below, the input field loses focus after typing a character. While using Chrome's Inspector, it looks like the whole form is being re-rendered instead of just the value attribute of the input field when typing.

eslint或Chrome Inspector都没有错误.

I get no errors from either eslint nor Chrome Inspector.

当表单位于渲染器的返回中或作为单独的组件导入时(而不是我在下面的编码方式中)，提交表单本身的方式与实际输入字段的作用相同.

Submitting the form itself works as does the actual input field when it is located either in the render's return or while being imported as a separate component but not in how I have it coded below.

为什么会这样?

主页组件

import React, { Component, PropTypes } from 'react';
import { connect } from 'react-redux';
import { bindActionCreators } from 'redux';
import * as actionPost from '../redux/action/actionPost';
import InputText from './form/InputText';
import InputSubmit from './form/InputSubmit';

class _PostSingle extends Component {
    constructor(props, context) {
        super(props, context);
        this.state = {
            post: {
                title: '',
            },
        };
        this.onChange = this.onChange.bind(this);
        this.onSubmit = this.onSubmit.bind(this);
    }
    onChange(event) {
        this.setState({
            post: {
                title: event.target.value,
            },
        });
    }
    onSubmit(event) {
        event.preventDefault();
        this.props.actions.postCreate(this.state.post);
        this.setState({
            post: {
                title: '',
            },
        });
    }
    render() {
        const onChange = this.onChange;
        const onSubmit = this.onSubmit;
        const valueTitle = this.state.post.title;
        const FormPostSingle = () => (
            <form onSubmit={onSubmit}>
                <InputText name="title" label="Title" placeholder="Enter a title" onChange={onChange} value={valueTitle} />
                <InputSubmit name="Save" />
            </form>
        );
        return (
            <main id="main" role="main">
                <div className="container-fluid">
                    <FormPostSingle />
                </div>
            </main>
        );
    }
}

_PostSingle.propTypes = {
    actions: PropTypes.objectOf(PropTypes.func).isRequired,
};

function mapStateToProps(state) {
    return {
        posts: state.posts,
    };
}

function mapDispatchToProps(dispatch) {
    return {
        actions: bindActionCreators(actionPost, dispatch),
    };
}

export default connect(mapStateToProps, mapDispatchToProps)(_PostSingle);

文本输入组件

import React, { PropTypes } from 'react';

const InputText = ({ name, label, placeholder, onChange, value, error }) => {
    const fieldClass = 'form-control input-lg';
    let wrapperClass = 'form-group';
    if (error && error.length > 0) {
        wrapperClass += ' has-error';
    }
    return (
        <div className={wrapperClass}>
            <label htmlFor={name} className="sr-only">{label}</label>
            <input type="text" id={name} name={name} placeholder={placeholder} onChange={onChange} value={value} className={fieldClass} />
            {error &&
                <div className="alert alert-danger">{error}</div>
            }
        </div>
    );
};

InputText.propTypes = {
    name: PropTypes.string.isRequired,
    label: PropTypes.string.isRequired,
    placeholder: PropTypes.string.isRequired,
    onChange: PropTypes.func.isRequired,
    value: PropTypes.string,
    error: PropTypes.string,
};

InputText.defaultProps = {
    value: null,
    error: null,
};

export default InputText;

提交按钮组件

import React, { PropTypes } from 'react';

const InputSubmit = ({ name }) => {
    const fieldClass = 'btn btn-primary btn-lg';
    return (
        <input type="submit" value={name} className={fieldClass} />
    );
};

InputSubmit.propTypes = {
    name: PropTypes.string,
};

InputSubmit.defaultProps = {
    name: 'Submit',
};

export default InputSubmit;

推荐答案

这是因为您正在render()内部的函数中呈现表单.

it is because you are rendering the form in a function inside render().

每次状态/属性更改时，该函数都会返回一个新表格.它使您失去了注意力.

Every time your state/prop change, the function returns a new form. it caused you to lose focus.

尝试将函数内部的内容直接放入渲染器中.

Try putting what's inside the function into your render directly.

       <main id="main" role="main">
            <div className="container-fluid">
                <FormPostSingle />
            </div>
        </main>

====>

       <main id="main" role="main">
            <div className="container-fluid">
                <form onSubmit={onSubmit}>
                    <InputText name="title" label="Title" placeholder="Enter a title" onChange={onChange} value={valueTitle} />
                    <InputSubmit name="Save" />
                </form>
            </div>
        </main>

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