如何访问Angular 2中VideoJs函数中的成员变量和方法？

Question

I am using videojs plugin in my angular project. I am trying to access the values and methods in the videojs method, but its showing the undefined values when the component initialized. I tried to call to videojs method in ngAfterViewInit also but its still not showing the values of component in videojs method.how can i show variable values in videojs method? can anyone help me?

Component code :

import {Component,OnInit} from '@angular/core';
declare var videojs :any;

@Component({
  selector: 'app-play-video',
  templateUrl: './play-video.component.html',
  styleUrls : [] 
 })
export class PlayVideoComponent implements OnInit{
public videoJSplayer :any;
public videoUrl :string;

constructor(){
this.videoUrl = 'http://clips.vorwaerts-gmbh.de/VfE_html5.mp4';
}
showValues(){
console.log("show Values method called"); 
}
  ngOnInit() {
    this.videoJSplayer = videojs(document.getElementById('play_video_id'), {}, function() { 
          console.log(this.videoUrl);  // here the video url value is undefined
          this.showValues(); // this also undefined
          this.play();
          }
    }
  }

play-video.component.html :

<video id="play_video_id" class="video-js vjs-default-skin vjs-big-play-centered"
  controls preload="auto" width="640" height="264"
  poster="http://video-js.zencoder.com/oceans-clip.png"
  data-setup='{"example_option":true}'>
  <source [src] = videoUrl  type="video/mp4" />
</video>

Answer 1

You have to use ES6 arrow functions for callbacks to get the correct this context inside your callback. When you use the function() {} syntax the this inside will vary based on the calling context:

this.videoJSplayer = videojs(document.getElementById('play_video_id'), {}, () => { 
          // `this` will point to the current `PlayVideoComponent` instance
     }
)