Use provider in app.component.ts

Ionic Framework ionic-v3
1

Hello,

I want to put my SQLite Code in a separate file. The file looks like this:

sqlitehelper.ts:

import { Injectable } from '@angular/core';
import { SQLite } from 'ionic-native';
import 'rxjs/add/operator/map';

@Injectable()
export class SQLiteHelper{

    private _db: any;

    constructor(){
        this._db = new SQLite();
        console.log("SQL CONSTRUCTOR");
    }

    private dbOpen(){
        this._db.openDatabase({
            name: 'data.db',
            location: 'default'
        }).then(() => {
            console.log("SQL OPEN");
        }, (err) => {
            console.error('Unable to open database: ', err);
        });
    }

    public dbCreateTables(){
        console.log("SQL CREATE TABLES");
        this.dbOpen();
        this._db.executeSql('CREATE TABLE IF NOT EXISTS medis(id INT PRIMARY KEY, wirk TEXT)', {}).then(() => {
            console.log("SQL TABLE CREATED");
        }, (err) => {
            console.error('Unable to execute sql: ', err);
        });
        this._db.close();
    }
}

in the app.module.ts I add it as provider:

import { SQLiteHelper } from '../providers/sqlitehelper';
[...]
providers: [SQLiteHelper]

my app.component.ts looks like this:

import { Component, ViewChild } from '@angular/core';
import { Nav, Platform } from 'ionic-angular';
import { StatusBar, Splashscreen } from 'ionic-native';
import { SQLiteHelper } from '../providers/sqlitehelper';

import { Page1 } from '../pages/page1/page1';
import { Page2 } from '../pages/page2/page2';


@Component({
  templateUrl: 'app.html'
})
export class MyApp {
  @ViewChild(Nav) nav: Nav;

  rootPage: any = Page1;

  pages: Array<{title: string, component: any}>;

  constructor(public platform: Platform, public db: SQLiteHelper ) {
    this.initializeApp();

    this.pages = [
      { title: 'Page One', component: Page1 },
      { title: 'Page Two', component: Page2 }
    ];

  }

  initializeApp() {
    this.platform.ready().then(() => {
        StatusBar.styleDefault();
        Splashscreen.hide();
        this.db.dbCreateTables;
    });
  }

  openPage(page) {
    this.nav.setRoot(page.component);
  }
}

I get the log from the constructor but it doesn’t execute the dbCreateTables methode.

2

shouldn’t it be this.db.dbCreateTables() in app.component.ts?

1 Like
3

Yes you are right, was my fault. but didn’t get any error massage, and didn’t saw the error.

thx for help

4

if we shouldn’t call this.db.dbCreateTables() in app.component.ts how should we call …?

5

How should I call the function?

6

Please tell then how it must be call ???

7

The issue is not the name of the function but the omission of () which is needed to trigger the function call