javascript - 来自服务的数据请求不起作用

Question

我正在使用服务从 json 服务器检索数据，但是，当我在服务内部创建一个 console.log() 时，控制台会向我显示从 json 检索的数据，但是当我尝试退出服务时，出现以下错误:

加载home.service

import { Injectable } from '@angular/core';

import { API } from '../../app.api'

import { HttpClient } from '@angular/common/http'

@Injectable()

export class LoadHomeService {

  constructor(private http: HttpClient) { 

  }

  getTarefasInternas(): any {
    return this.http.get(`${API}/getTarefasInternas`)
      .subscribe((response) =>{
        console.log (response) // it works
      } 
  )}

  getTarefasExternas(): any {
    return this.http.get(`${API}/home`)
      .subscribe((response) =>{}
  )}
}

home.page.ts

import { Component } from '@angular/core';
import { LoadHomeService } from './load-home.service';

@Component({
  selector: 'app-home',
  templateUrl: './home.page.html',
  styleUrls: ['./home.page.scss'],
})
export class HomePage  {
  tarefasInternas : any
  constructor(private homeService: LoadHomeService) { }

  ngOnInit() {
    this.tarefasInternas = this.homeService.getTarefasInternas()

  }
}

HTML 标记:

<ion-list>
    <ion-item *ngFor="let tarefa of tarefasInternas" class="in-list item ion-focusable item-label hydrated">
      <ion-label class="sc-ion-label-ios-h sc-ion-label-ios-s hydrated">
        <h2>{{tarefa.descricao}}</h2>
        <h3>{{tarefa.inicio}} - {{tarefa.fim}}</h3>
        <p>{{tarefa.comentario}}</p>
      </ion-label>
    </ion-item>
  </ion-list>

当我从服务中调用 console.log 时:

Answer 1

如下更改您的服务方法并在您的组件中订阅，

getTarefasInternas(): any {
    return this.http.get(`${API}/getTarefasInternas`)
)}

以及组件中

ngOnInit() {
this.homeService.getTarefasInternas().subscribe((data)=>{
    this.tarefasInternas = data;
});
}