angular - 我如何在 Angular 4 中放置 Google 图表

Question

如何将 google 图表集成到 angular 4 应用程序中？

我阅读了 SO 问题的答案 here ，但我认为它是不完整的。基本上，我正在尝试与之前的答案相同的策略，使用 GoogleChartComponent 和另一个扩展它的组件。出现两个错误，第一个是子组件缺少对 super() 的调用，第二个是此代码中对“new”的调用

  createBarChart(element: any): any {
      return new google.visualization.BarChart(element);
  }

我收到错误“google.visualization.BarChart 不是构造函数”。

我看到其中一条评论还提到了 <ng-content> 的使用用于数据投影，但没有明确概述。

在尝试提出一个“好”问题时，这是我的 GoogleChartComponent:

export class GoogleChartComponent implements OnInit {
  private static googleLoaded: any;
  constructor() {
    console.log('Here is GoogleChartComponent');
  }

  getGoogle() {
    return google;
  }

  ngOnInit() {
    console.log('ngOnInit');
    if (!GoogleChartComponent.googleLoaded) {
      GoogleChartComponent.googleLoaded = true;
      google.charts.load('current', {
        'packages': ['bar']
      });
      google.charts.setOnLoadCallback(() => this.drawGraph());
    }
  }

  drawGraph() {
      console.log('DrawGraph base class!!!! ');
  }

  createBarChart(element: any): any {
      return new google.visualization.BarChart(element);
  }

  createDataTable(array: any[]): any {
      return google.visualization.arrayToDataTable(array);
  }
}

以及扩展它的子组件:

@Component({
  selector: 'app-bitcoin-chart',
  template: `
   <div id="barchart_material" style="width: 700px; height: 500px;"></div>
  `,
  styles: []
})
export class BitcoinChartComponent extends GoogleChartComponent  {
 private options;
  private data;
  private chart;
  // constructor() {
  //   super();
  //   console.log('Bitcoin Chart Component');
  // }
  drawGraph() {
    console.log('Drawing Bitcoin Graph');
    this.data = this.createDataTable([
     ['Price', 'Coinbase', 'Bitfinex', 'Poloniex', 'Kraken'],
     ['*', 1000, 400, 200, 500]
    ]);

    this.options = {
     chart: {
                    title: 'Bitcoin Price',
                    subtitle: 'Real time price data across exchanges',
                },
                bars: 'vertical' // Required for Material Bar Charts.
    };

    this.chart = this.createBarChart(document.getElementById('barchart_material'));
    this.chart.draw(this.data, this.options);
  }
}

Answer 1

我相信有更好的方法可以将 Google Chart 集成到 Angular 4 中。库 ng2-google-charts已经有 GoogleChartComponent。 npm 页面的链接很好地描述了如何使用它。以下是组件示例:

import {Component, ViewEncapsulation, OnInit} from '@angular/core';
import {Component, ViewEncapsulation, OnInit} from '@angular/core';
import {Component, ViewEncapsulation, OnInit} from '@angular/core';
import {ViewChild} from '@angular/core';

import {GoogleChartComponent} from 'ng2-google-charts';

// needed for advanced usage of ng2-google-charts
import {HostListener} from '@angular/core';

@Component({
  selector: '[your-widget]',
  templateUrl: './your-widget.html',
  encapsulation: ViewEncapsulation.None
})
export class YourWidget implements OnInit {

  // type GoogleChartComponent and import for it can be ommited
  @ViewChild('your_chart') chart: GoogleChartComponent;

  // shows spinner while data is loading
  showSpinner: boolean;

  public chartData = {
    chartType: 'AnyChartType', // your type
    dataTable: [
      ['Col1', 'Col2']
    ],
    options: {}
  };

  constructor() {
  }

  ngOnInit(): void {

    this.showSpinner = true;
    this.yourService.getData()
          .subscribe((data) => {
            //this.data = data;
            this.processYourData();
            this.showSpinner = false;
        });
      }

  private processYourData() {
  }

  // advanced usage of chart
  //   in this case redraw function on window:resize event
  @HostListener('window:resize', ['$event'])
  onWindowResize(event: any) {
    // console.log(event.target.innerWidth);
    // Make sure you don't call redraw() in ngOnInit()
    //   - chart would not be initialised by that time, and
    //   - this would cause chart being drawn twice
    this.chart.redraw(); 
  }
}

你的标记看起来像这样:

<header class="widget-handle">
  <h5>Widget Title</h5>
  <div class="widget-controls">
    <a title="Refresh">
      <i *ngIf="showSpinner" class="fa fa-refresh fa-spin"></i>
    </a>
  </div>
</header>

<div class="widget-body">
  <google-chart #your_chart [data]="chartData" *ngIf="!showSpinner">
  </google-chart>
</div>