它不能从Ionic连接到我的远程数据库

Question

我在Fauxten上创建了一个数据库，现在我正在尝试将它连接到我的项目中。我可以在浏览器上打开链接，但当我尝试在应用程序中调用它时，没有任何反应。我看不出我遗漏了什么

import { Injectable } from '@angular/core';
import PouchDB from 'pouchdb';
import { HttpClient } from '@angular/common/http';


@Injectable({
  providedIn: 'root'
})

export class ApiService {
  private db;
  url = 'http://localhost:5984/_utils/#database/grundbaustein/_all_docs';
constructor(private http: HttpClient) { }


  setUpPDB() {
    this.db = new PouchDB(this.url);
  }

  getdataDB() {
    this.http.get(this.url).subscribe((res) => {
      console.log(res);
    });

    }

  }

我想用来访问我的数据库的服务

import { Component } from '@angular/core';
import { ApiService } from '../api.service';
@Component({
  selector: 'app-home',
  templateUrl: 'home.page.html',
  styleUrls: ['home.page.scss'],
})
export class HomePage  {

  constructor(private api: ApiService) { }

ionViewDidLoad() {
this.api.setUpPDB();
this.api.getdataDB();

  }
}

这就是我的Page.ts，我想在这里使用我从数据库中获得的信息。

{
  "name": "firstapp",
  "version": "0.0.1",
  "author": "Ionic Framework",
  "homepage": "https://ionicframework.com/",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/common": "~8.1.2",
    "@angular/core": "~8.1.2",
    "@angular/forms": "~8.1.2",
    "@angular/platform-browser": "~8.1.2",
    "@angular/platform-browser-dynamic": "~8.1.2",
    "@angular/router": "~8.1.2",
    "@ionic-native/core": "^5.0.0",
    "@ionic-native/http": "^5.17.1",
    "@ionic-native/splash-screen": "^5.0.0",
    "@ionic-native/status-bar": "^5.0.0",
    "@ionic/angular": "^4.7.1",
    "@types/pouchdb": "^6.4.0",
    "cordova-plugin-advanced-http": "^2.3.0",
    "core-js": "^2.5.4",
    "pouchdb": "^7.1.1",
    "rxjs": "~6.5.1",
    "tslib": "^1.9.0",
    "zone.js": "~0.9.1"
  },
  "devDependencies": {
    "@angular-devkit/architect": "~0.801.2",
    "@angular-devkit/build-angular": "~0.801.2",
    "@angular-devkit/core": "~8.1.2",
    "@angular-devkit/schematics": "~8.1.2",
    "@angular/cli": "~8.1.2",
    "@angular/compiler": "~8.1.2",
    "@angular/compiler-cli": "~8.1.2",
    "@angular/language-service": "~8.1.2",
    "@ionic/angular-toolkit": "^2.1.1",
    "@types/jasmine": "~3.3.8",
    "@types/jasminewd2": "~2.0.3",
    "@types/node": "~8.9.4",
    "codelyzer": "^5.0.0",
    "jasmine-core": "~3.4.0",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~4.1.0",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~2.0.1",
    "karma-jasmine": "~2.0.1",
    "karma-jasmine-html-reporter": "^1.4.0",
    "protractor": "~5.4.0",
    "ts-node": "~7.0.0",
    "tslint": "~5.15.0",
    "typescript": "~3.4.3"
  },
  "description": "An Ionic project",
  "cordova": {
    "plugins": {
      "cordova-plugin-advanced-http": {}
    }
  }
}

Answer 1

您并不是在ionViewDidLoad中调用getdataDB，而只是在调用setUpPDB。因此，不会调用该方法，也不会发出get请求

更新

ngOnInit不会像ionViewDidLoad那样工作，因为它只在组件创建时工作一次，而不是每次导航到离子页面时都起作用。但是尝试一下这个，看看你是否已经找到了这个组件

试试这个，让我知道会发生什么：

import { Component, OnInit } from '@angular/core';
import { ApiService } from '../api.service';
@Component({
  selector: 'app-home',
  templateUrl: 'home.page.html',
  styleUrls: ['home.page.scss'],
})
export class HomePage implements OnInit {

  constructor(private api: ApiService) { }

  ngOnInit() {
    this.api.setUpPDB();
    this.api.getdataDB();

  }
}