Question

从组件调用服务时出错。我试图从提供的URL中获取一些返回JSON的数据。每次运行此代码时，HTML都会成功加载，但不会调用URL，因为它在getData（）上给出了错误，它不是函数运行时遇到错误。应该采取什么方法来解决它？

this.dashboardService.getData此行中的问题是什么。

Here is the code:

**app.component.ts**

import { Component } from '@angular/core';
import { DashboardService } from './dashboard.service';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'app';

  private apiUrl: "someURL";


  constructor(private dashboardService: DashboardService) { 
    this.getEntries();
  }


  getEntries(){
    this.dashboardService.getData(this.apiUrl).subscribe(data => {
      console.log("data" , data) ;
    })
  }


}



**dashboard.service.ts**

import { Injectable } from '@angular/core';
import {Http, Response} from '@angular/http';
import 'rxjs/add/operator/map';

@Injectable()
export class DashboardService {

  constructor(private http: Http) { }

  getData(apiUrl){
    return this.http.get(apiUrl)
     .map((res: Response) => res.json());
   }
}


**app.module.ts**

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';


import { AppComponent } from './app.component';
import { DashboardComponent } from './dashboard/dashboard.component';
import { DashboardService } from './dashboard.service';


@NgModule({
  declarations: [
    AppComponent,
    DashboardComponent
  ],
  imports: [
    BrowserModule
  ],
  providers: [DashboardService],
  bootstrap: [AppComponent]
})
export class AppModule { }

Answer 1

您缺少AppModule中的HttpModule导入

AVAudioPCMBuffer

Answer 2

即使错误是 this.dashboardService.getData ，它也会使用HttpClientModule，因为你没有在导入下导入HttpClientModule，它会抛出错误。

修复，添加

 import { HttpClientModule } from '@angular/http';

也可以在导入下添加。

imports: [
       BrowserModule,
       HttpClientModule
]

app.under module.ts

也在您的dashboardService

中

constructor(private http: HttpClient){
}

错误TypeError：this.dashboardService.getData不是函数

2 个答案: