var that = this
				let tempIndex
				//随机
				if (that.playWay == 2) {
					let temp = Math.floor(Math.random() * this.assetsList.length);
					temp === this.assetsList.length - 1 ? (temp) : (temp++)
					tempIndex = temp
				} else if (that.playWay == 1) { //顺序播放
					//顺序
					if (this.nowIndex >= (this.assetsList.length - 1)) {
						tempIndex = 0
					} else {
						tempIndex = this.nowIndex + 1
					}
				} else { //单曲播放 不做处理
					if (this.nowIndex >= (this.assetsList.length - 1)) {
						tempIndex = 0
					} else {
						tempIndex = this.nowIndex + 1
			
					}
				}
				this.$store.commit('song/setSongIndex', tempIndex)
				this.bgAudioMannager.startTime = 0
				this.$store.commit('song/setSongId', that.assetsList[this.nowIndex].id)
				that.bgAudioInnit()
    然后在bgAudioInnit这个方法中，vuex中的setSongIndex设置的索引有问题。并没有变化。这种问题只在把小程序背景音乐放入后台才会出现。其他情况不会发生