问只有在父组件完成重新呈现后才调用子组件中的方法。

EN

class HeatMap extends Component {
  constructor (props) {
    super(props);
    this.state = {
      getSVG: false,
      loadedData: [],
    }
  }
  render () {
   const { getSVG, loadedData } = this.state;
   return (
    <Fragment>
      {getSVG
        ? <HeatmapSeries colorType="literal" data={loadedData} /> // svg graph
        : <HeatmapSeriesCanvas colorType="literal" data={loadedData} />} // png(low-qlty)
      <MyButton 
        {...this.props}
        svgFunction={(required) => this.setState({ getSVG: true})}
        getSVG={getSVG} 
       />
    </Fragment>
  )
  }
}

class MyButton extends Component {
  render() {
    return (
      <Button size="small" icon="download" onClick={this._downloadSVG} >SVG</Button>
    )
  }
  /**
   * Generate the image and the download action
   * @return {void}
  **/
  async _downloadSVG() {
    const { svgFunction } = this.props;
    if (typeof svgFunction === 'function') {
      svgFunction(); // re-render the graph as a vector (try to re-render parent first)
    }
    methodToDownloadGraph({...this.props}); // graph svg is passed as argument
  }
}