如何在React JS的todo应用程序中使用onchange，onclick，onkeypress？

Question

我创建了一个待办事项应用程序，它工作正常。但我想，当我按下enter显示任务。 onclick和onchange事件运行正常。需要onkeypress事件事件添加为好。

import React, { Component } from 'react'


 class Todolist extends Component {

   constructor(props) {
     super(props)

     this.state = {

      userinput : "",

      list : [],

      title : " My simple todo app"
     }

   }

  /
   changeUserInput (input){

  this.setState({

    userinput : input
  })
   }

   addToList (input){

     const listArray = this.state.list

     listArray.push(input);

     this.setState ({

      list : listArray,

      userinput : "",
     })
   }



  render() {
    return (

      <div className="todolistmain">

      <h2 style={{color:"red"}} >{this.state.title}</h2>


     <input 


      onChange={(e)=>this.changeUserInput(e.target.value)}
      onKeyPress={e => {
        if (e.key === 'Enter') {
          this.changeUserInput()
        }
      }}
      value={this.state.userinput} type="text"
      placeholder="Enter task!!"/>


      <button style={{color:"blue"}} onClick={()=>this.addToList(this.state.userinput)}>New Task</button>

      <ul style={{color:"green"}}>
        {this.state.list.map((val)=><li>{val}</li>)}
      </ul>
      </div>
    )
  }
}
export default Todolist

Answer 1

使用keyCode

  onKeyPress={e => {
    if (e.keyCode === 13) {
      this.changeUserInput()
    }
  }}

class Todolist extends React.Component {

    constructor(props) {
        super(props)

        this.state = {

            userinput : "",

            list : [],

            title : " My simple todo app"
        }

    }


    changeUserInput (input){

        this.setState({

            userinput : input
        })
    }

    addToList (input){

        const listArray = this.state.list

        listArray.push(input);

        this.setState ({

            list : listArray,

            userinput : "",
        })
    }



    render() {
        return (

            <div className="todolistmain">

                <h2 style={{color:"red"}} >{this.state.title}</h2>


                <input
                    onChange={(e)=>this.changeUserInput(e.target.value)}
                    onKeyDown={e => {
                        if (e.keyCode === 13) {
                            this.addToList(this.state.userinput)
                        }
                    }}
                    value={this.state.userinput} type="text"
                    placeholder="Enter task!!"/>


                <button style={{color:"blue"}} onClick={()=>this.addToList(this.state.userinput)}>New Task</button>

                <ul style={{color:"green"}}>
                    {this.state.list.map((val)=><li>{val}</li>)}
                </ul>
            </div>
        )
    }
}


ReactDOM.render(<Todolist/> , document.getElementById('root'))

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id='root'>

</div>