[LayaAir 2.0]Cannot read property 'offCanplay' of null

Cannot read property 'offCanplay' of null

TypeError: Cannot read property 'offCanplay' of null

at n.onCanPlay (https://usr/game.js:39:9226)

at Function.t (https://lib/WAGameSubContext.js:2:153278)

Cannot read property 'offCanplay' of null;at audioContext.oncanplay callback function

TypeError: Cannot read property 'offCanplay' of null

at n.onCanPlay (https://usr/game.js:39:9226)

at Function.t (https://lib/WAGameSubContext.js:2:148325)

  onCanPlay() {

	        this.loaded = true;

	        this.event(Laya.Event.COMPLETE);

	        this._sound.offCanplay(null);

	    }

	    onCanPlay() {

	        this.loaded = true;

			this.event(Laya.Event.COMPLETE);

			if(this._sound){

				this._sound.offCanplay(null);

			}

	    }