如何使用 React 渲染组件 onClick？

Question

我正在尝试渲染从父组件传递的特定位置的地图。我正在使用 google-maps-react，我不确定两件事：

如何在渲染中使用 onClick 调用函数。以及如何在我的 class 中编写呈现我想要的组件的函数。这是我目前所拥有的：

import React, { Component } from 'react';
import yelp from 'yelp-fusion';
import xhr from 'xhr';
import GoogleMapContainer from './Map';

class BusinessCard extends Component {
  constructor () {
    super()

    this.renderMap = this.renderMap.bind(this);
  }

  renderMap(){
    <GoogleMapContainer barLat={bar.coordinates.latitude} barLong={bar.coordinates.longitude} />
  }

  render() {
    const newCard = this.props.newCard
    const bar = this.props.selectedBar
    // console.log("this are the coordinates", bar["coordinates"])
    if(bar.coordinates){
      return (
        <div>
          <p>{bar.coordinates.longitude}</p>
          <p>{bar.name}</p>
          <img src={bar.image_url} />
          <button> X </button>
          <button onClick={newCard}> Yes </button>

        </div>
      )
    } else {
      return(
        <div>Loading...</div>
      )
    }
  }
}

export default BusinessCard;

目前，编译存在问题，因为 bar 在呈现时未定义。任何 suggestions/advice?

Answer 1

首先，在 React 组件中，render() method is your bridge between the virtual DOM (kept in memory by React) and the concrete DOM that is shown to the user. I'd read more about a React component's lifecycle - 理解这个就是理解 React。

此外，为了在页面上显示您的GoogleMapContainer，您需要在React render()方法中调用您的方法renderMap()，将结果存储在一个变量中并return它。

要在 onClick 中调用多个函数是完全可能的，请将一个函数传递给处理程序并在那里调用您想要的函数数。

检查这个例子：

import React, { Component } from 'react';
import yelp from 'yelp-fusion';
import xhr from 'xhr';
import GoogleMapContainer from './Map';

class BusinessCard extends Component {
  constructor (props) {
    super(props)

    // LOOK MORE WHAT 'this' means!! <- the key of javascript = execution context
    this.renderMap = this.renderMap.bind(this);
    this.handleClick = this.handleClick.bind(this);
  }

  renderMap(){
    // careful!!! bar is undefined. Look more what 'this' means in javascript
    const bar = this.props.selectedBar;
    return (
      <GoogleMapContainer barLat={bar.coordinates.latitude} barLong={bar.coordinates.longitude} />
    );
  }

  handleClick() {
    const newCard = this.props.newCard;

    // call the newCard function prop (if only is a function!!!)
    newCard();

    // another method call
    this.anotherMethod();
  }

  anotherMethod() {
    console.log('heyo!');
  }

  render() {
    const newCard = this.props.newCard
    const bar = this.props.selectedBar
    // console.log("this are the coordinates", bar["coordinates"])
    if(bar.coordinates){
      const renderMap = this.renderMap();
      return (
        <div>
          <p>{bar.coordinates.longitude}</p>
          <p>{bar.name}</p>
          <img src={bar.image_url} />
          <button> X </button>
          <button onClick={this.handleClick}> Yes </button>
          { renderMap }
        </div>
      )
    } else {
      return(
        <div>Loading...</div>
      )
    }
  }
}

如何使用 React 渲染组件 onClick？

How to render a component onClick with React?

reactjs

npm

jsx

google-maps-react