将AngularFire数据等待异步数据后绑定到属性中

Question

我想使用包含lat / lng坐标的URL参数从AngularFire的Firestore中获取get的特定文档，然后将这些坐标绑定到google-map组件的[center]属性以根据查看的项目动态显示地图。但是数据未连接到google map属性，因此默认情况下以Google HQ位置为中心。

主组件List在URL hike/:hikeId中传递事件的ID，我提取了该事件，然后使用AngularFire来获取文档。

hike-detail.component.html

<h1>Hike Detail</h1>
<h3>Name: <span>{{ (hikeInfo | async)?.name }}</span></h3>  // Displays Hike A
<google-map
    [center]="hikeInfo.center | async"
    width="100%">
</google-map>

hike-detail.component.ts

import { Component, OnInit, Input } from '@angular/core';
import { Router, ActivatedRoute } from '@angular/router';
import { Location } from '@angular/common';
import { AngularFirestore, AngularFirestoreDocument } from '@angular/fire/firestore';
import { Observable } from 'rxjs';
import { stringify } from 'querystring';
import { map } from 'rxjs/operators';


@Component({
  selector: 'app-hike-detail',
  templateUrl: './hike-detail.component.html',
  styleUrls: ['./hike-detail.component.css']
})
export class HikeDetailComponent implements OnInit {
  hikeId;
  hikeInfo;
  center: google.maps.LatLngLiteral;

  constructor(
    private route: ActivatedRoute,
    private location: Location,
    private router: Router,
    private firestore: AngularFirestore
  ) { }

  ngOnInit(): void {
    this.hikeId = this.route.snapshot.paramMap.get('id');
    this.hikeInfo = this.firestore.collection('hikes').doc(this.hikeId).valueChanges(); 
  }
}

数据库

firestore
   -- hikes
      -- key
         -- name: Hike A
         -- center: {
             lat: 28.12,
             lng: 32.71
            }

当前显示名称和以通用Google HQ为中心的google地图，也可以使用[center]绑定。

Answer 1

this.hikeInfo = this.firestore.collection('hikes').doc(this.hikeId).valueChanges(); 
this.hikeInfo.subscribe(items => {
  console.log(items);
  this.center = items.center;
});

然后您可以在html中执行：

<google-map
    [center]="center"
    width="100%">
</google-map>