Question

我制作了2个按钮和1个输入框，用于显示JSON数据的日期。当我点击递增或递减按钮时，它应显示data.available_slots[0].data_slots

如果data.available_slots[this.state.counter].data_slots === 0，则除了输入框之外，它应显示“今天没有可用的插槽”。

data.js：

const data = {
        "template_type": "slot_picker",
        "selection_color": "#000000",
        "secondary_color": "#808080",
        "title": "Available Slots for Dr. Sumit",
        "available_slots": [
          {
            "date": "Wed, Dec 06",
            "date_slots": [

            ]
          },
          {
            "date": "Thu, Dec 07",
            "date_slots": [

            ]
          },
          {
            "date": "Fri, Dec 08",
            "date_slots": [

            ]
          },
          {
            "date": "Sat, Dec 09",
            "date_slots": [

            ]
          },
          {
            "date": "Today",
            "date_slots": [
              {
                "hour": "8",
                "hour_slots": [
                  {
                    "08:10 AM": "slotId001"
                  },
                  {
                    "08:50 AM": "slotId005"
                  }
                ]
              },
              {
                "hour": "3",
                "hour_slots": [
                  {
                    "03:00 PM": "slotId005"
                  },
                  {
                    "03:30 PM": "slotId007"
                  }
                ]
              }
            ]
          },
          {
            "date": "Tomorrow",
            "date_slots": [

            ]
          },
          {
            "date": "Wed, Dec 13",
            "date_slots": [
              {
                "hour": "4",
                "hour_slots": [
                  {
                    "04:30 PM": "slotId105"
                  },
                  {
                    "04:50 PM": "slotId106"
                  }
                ]
              },
              {
                "hour": "5",
                "hour_slots": [
                  {
                    "05:30 PM": "slotId202"
                  },
                  {
                    "05:45 PM": "slotId208"
                  }
                ]
              }
            ]
          }
        ]
      };

 export default data;

datepicker.js：

import React, { Component } from 'react';
import data from './data';
import './datepicker.css';

class DatePicker extends Component {

  constructor(props){
    super(props);
     this.state = {
        counter:0
     };
   }

  increment(){
    if(this.state.counter < 6){
      this.setState(prevState => ({counter: prevState.counter + 1}))
    }
    if(data.available_slots[this.state.counter].data_slots === 0){
        return(
            <p>No slots available for today</p>
            )
    }else{
        return(
            <p>Slots available for today</p>
            )
    }
  }

  decrement(){
    if(this.state.counter > 0){
      this.setState(prevState => ({counter: prevState.counter-1}))
   }
   if(data.available_slots[this.state.counter].data_slots === 0){
        return(
            <p>No slots available for today</p>
            )
    }else{
        return(
            <p>Slots available for today</p>
            )
    }
  }

  render() {
    return (
      <div>

        <div id="center">
        <div className="title">
            <p>Pick a Date</p>
        </div>
        <div className="increment">
          <button type="button" className="btn btn-success" id="plus" onClick={this.increment.bind(this)}>+</button>
        </div>
        <div className="display">
          <input type="text" id="date" value={data.available_slots[this.state.counter].date}/>
        </div>
        <div className="decrement">
          <button type="button" className="btn btn-danger" id="minus" onClick={this.decrement.bind(this)}>-</button> 
        </div>
        <div className="submit">
          <button type="button" class="btn btn-primary" id="submit">Set Date</button> 
        </div>
      </div>

      <div id="slotinfo">

      </div>


      </div>
    );
  }
}

export default DatePicker;

当我点击当天的加/减按钮时，如果当天的插槽可用，则应显示。因此increment()和decrement()函数除了输入框之外不会返回<p>元素。

截图：

Answer 1

increment和decrement函数只是返回<p>元素，并且不知道在哪里显示它们。

根据状态变量render，移动逻辑以在this.state.counter函数内呈现“今天没有可用的插槽”或“今天可用的插槽”。可以删除increment和decrement方法中的逻辑。

increment(){
  if(this.state.counter < 6){
    this.setState(prevState => ({counter: prevState.counter + 1}))
  }
}

decrement(){
  if(this.state.counter > 0){
    this.setState(prevState => ({counter: prevState.counter - 1}))
  }
}

在渲染功能中，

<div id="slotinfo">
  { data.available_slots[this.state.counter].date_slots.length === 0 ? 
      <p>No slots available for today</p> : <p>Slots available for today</p> }
</div>

如何在ReactJS中单击按钮时动态显示html内容？

1 个答案: