javascript - Vimeo API方法中的变量“ undefined”(Variable `undefined` in Vimeo API method)

Question

So I have embedded a vimeo video in my Angular 8 app and am now trying to trigger some animation after the video starts playing and once its ended.(因此，我已在Angular 8应用程序中嵌入了一个vimeo视频，现在尝试在视频开始播放并结束后触发一些动画。)

Essentially if screen width is <800 , the variable isMobile is true .(本质上，如果屏幕宽度<800 ，则变量isMobile为true 。) Next I have the vimeo play method being called which checks if isMobile is true , and sets load_completed (which is the animation trigger) to true .(接下来，调用load_completed play方法，该方法检查isMobile是否为true ，并将load_completed （这是动画触发器）设置为true 。) The isssue is that my variable isMobile returns undefined , why is that?(问题是我的变量isMobile返回undefined ，为什么呢？) isMobile = false; constructor() { } ngOnInit() { this.innerWidth = window.innerWidth; console.log(this.innerWidth); if (this.innerWidth < 800) { this.isMobile = true; } var iframe = document.querySelector('iframe'); var player = new Vimeo.Player(iframe); player.on('play', function() { //isMobile returns undefined why? console.log(this.isMobile); if (this.isMobile) { this.load_completed = true; } console.log('Played the video'); }); player.on('ended', function(data) { console.log('Video ended'); }); }   ask by kontenurban translate from so

Answer 1

Try using arrow function as follows , here is the explanation(尝试如下使用arrow function ，这是explanation)

player.on('play',()=>{ console.log(this.isMobile); })