Question

我需要帮助我的Angular代码。我只想从Firebase获取数据，但控制台日志返回带有空对象的数组。我已经从我的Firebase创建了数据！这是我的服务：

import { Injectable } from '@angular/core';
import { AngularFirestore, AngularFirestoreCollection, AngularFirestoreDocument } from 'angularfire2/firestore';
import { Item } from '../models/Item';
import { Observable } from 'rxjs/Observable';

@Injectable()

export class ItemService {   
itemsCollection: AngularFirestoreCollection<Item>;   
items: Observable<Item[]>;

constructor(public afs: AngularFirestore) {
    this.items = this.afs.collection('/items').valueChanges();   
}

 getItems() {
   return this.items;   
 }
}

这是我的组件

import { Component, OnInit } from '@angular/core';
import { ItemService } from '../../services/item.service';
import { Item } from '../../models/Item';

@Component({
  selector: 'app-items',
  templateUrl: './items.component.html',
  styleUrls: ['./items.component.css']
})
export class ItemsComponent implements OnInit {
  items: Item[];

  constructor(private itemService: ItemService) { }

  ngOnInit() {
    this.itemService.getItems().subscribe(items => {
      console.log(items);
      this.items = items;
    });
  }

}

这是我的模板：

<div *ngIf="items?.length > 0;else noItem">
  <ul *ngFor="let item of items | async">
    <li>
      {{item.title}}
    </li>
  </ul>
</div>

<ng-template #noItems>
  <hr>
  <h5>No Items</h5>
</ng-template>

我的结果在Array中没什么。你能帮助我吗，非常感谢！

Angular is running in the development mode. Call enableProdMode() to enable the production mode.
core.js:3687
Array []

Answer 1

这是因为在分配订阅值之前，您正在安排items数组。试试这个

this.items = items;// First assign the value
console.log(this.items);// then Console it out

Angular：无法使用firestore从Firebase获取数据

1 个答案: