反应点击按钮的读取值 [英] React read value of button clicked

问题描述

很抱歉，如果这个话题可能是另一个话题的副本，但是我不明白我的代码在做什么错+我真的是新来的回应者.我尝试了几种解决方案，但没有一个起作用.我将在这里写一些我读过的帖子:

Sorry if this topic it's probably a copy of another one, but i don't understand what i'm doing wrong with my code + i'm really new to react. I tried several solutions but none of them worked. I will put here some of the post that i read:

• React js onClick无法将值传递给方法

如何获得被点击的按钮的ID?ReactJS

问题

Problem

我需要使用handleInput

I need to console.log the string inside value with handleInput

代码

Code

import React, {Component} from 'react';
import Button from './Button';
import Screen from './screen';
import './keyboard.css'

class NumberKeyboard extends Component {
    constructor(props){
        super(props)
        this.state = {
            operations: []
        }

    }

handleInput(props) {
    const buttonValue= this.props.value;
    console.log(buttonValue)
}


    render() {


        return (
            <div className="keyboard">
                <div className="column"></div>
                <div className="column">
                    <div className="keyboardRow roundBorder" value={"example"} onClick={() => this.handleInput('value')}>
                        <Screen className="crystalScreen"></Screen>
                        <Button value="clear" >C</Button> 
                        <Button value="±">±</Button>
                        <Button value=".">.</Button>
                        <Button value="">+</Button>
                    </div>
                    <div className="keyboardRow">
                        <Button value="clear">1</Button>
                        <Button value="2">2</Button>
                        <Button value="3">3</Button>
                        <Button value="-">-</Button>
                    </div>
                    <div className="keyboardRow">
                        <Button value="4">4</Button>
                        <Button value="5">5</Button>
                        <Button value="6">6</Button>
                        <Button value="*">X</Button>
                    </div>
                    <div className="keyboardRow lastRow">
                        <Button value="7">7</Button>
                        <Button value="8">8</Button>
                        <Button value="9">9</Button>
                        <Button value="%">÷</Button>
                    </div>
                </div>

                <div className="column"></div>
            </div>
        )
    }
}

export default NumberKeyboard;

我尝试了几次尝试来解决它，但是每次遇到的最大结果是令人遗憾的未定义或错误.

i tried several attempts to solve it but every time the max result that i had it was the sadly undefined or an error.

---------------------------更新-------------------------

--------------------------- UPDATE -------------------------

由于对这些帖子的访问，我也想稍作更新，并基于钩子设置一个示例:

Due to visits of these post i want to give a little update and set an example based on hooks too:

import React, { useState } from 'react';
import KeyboardRow from 'src/components/keyboardRow'; /* ideally this
 should contain the buttons element. i'm writing in this way just to stay 
 closer to the initial question */  

function NumberKeyboard() {
  const [selectedNumber, setSelectedNumber] = useState(0);

  const selectNumber = numberSelected => {
       setSelectedNumber(numberSelected)
  }

  return (
  <>
    <KeyboardRow >
       <Button onClick={selectNumber} value="7">7</Button>
       <Button onClick={selectNumber} value="8">8</Button>
       <Button onClick={selectNumber} value="9">9</Button>
    </KeyboardRow >
    <div>{selectedNumber}<div>
  </>
  );
}

推荐答案

您以错误的方式发送和接收数据.首先，您需要使用 onClick = {this.handleInput} 或 onClick = {(e)=>this.handleInput(e，'value')} 而不是 onClick = {()=>this.handleInput('value')} ，因为您要在函数中发送'value'个字符串.

You are sending and receiving data in a wrong way. First, you need to use onClick={this.handleInput} or onClick={(e) => this.handleInput(e,'value')} instead of onClick={() => this.handleInput('value')} because you are sending 'value' string in function.

<div className="keyboardRow roundBorder" value={"example"} onClick={e => this.handleInput(e, "value")} >

然后通过以下方式接收:

And then receive in following ways:

handleInput(e) {
    console.log(e.target.value);
}

您可以检查正在运行的演示.

You ca check the working demo.

这篇关于反应点击按钮的读取值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！