title: no provider for BarcodeScanner
body: <p>The code is as follows:</p>
  
  <pre>
  
      import { Component } from '@angular/core';
      import { NavController, Platform } from 'ionic-angular';
      import { TranslateService } from '@ngx-translate/core';
      import { BarcodeScanner } from '@ionic-native/barcode-scanner';
  
      @Component({
          selector: 'page-home',
          templateUrl: 'home.html'
      })
      export class HomePage {
          constructor(public navCtrl: NavController, private translate: TranslateService, private barcodeScanner: BarcodeScanner) {
  
          }
          //Switch language 
         changelanguage() {
              let browserLang = this.translate.currentLang;
              this.translate.use(browserLang.match(/en/) ? 'zh' : 'en');
          }
          //Scan test
          ScanCode() {
              this.barcodeScanner.scan()
                  .then((result) => {
                      console.log(result);
                  })
                  .catch((error) => {
                      alert(error);
                  });
          }
      }
  
  </pre>
  
  <p>Error Picture:</p>
  
  <p><a href="https://i.stack.imgur.com/UBOkm.png" rel="noreferrer"><img src="https://i.stack.imgur.com/UBOkm.png" alt="enter image description here"></a></p>
  
  <p>Reference：<a href="https://ionicframework.com/docs/native/barcode-scanner/" rel="noreferrer">https://ionicframework.com/docs/native/barcode-scanner/</a></p>
  
  <p><br/><br/>
  new questions arose:<br/>
  According to Suraj recommendations, the prompt "plugin_not_installed"
  <br/><br/>
  Error Picture:<br/>
  <img src="https://i.stack.imgur.com/IT6rE.png" alt="enter image description here"><br/>
  <img src="https://i.stack.imgur.com/i3yIo.jpg" alt="enter image description here">
  development environment:
  Visual Studio 2017</p>