bgAudioMannager设置新的src无法生效，切换

在uni-app的demo基础上加了一个按钮，点击给bgAudioMannager设置新的src，按道理该播放新的音频啊(文档说明，当设置了新的 src 时，会自动开始播放)

编辑器版本2.9.3

请问是什么原因啊，该如何修改才能播放另一首音频啊

<template>  
    <view>  
        <page-head :title="title"></page-head>  
        <view class="uni-padding-wrap">  
            <view class="uni-center">  
                <text class="time-big">{{formatedPlayTime}}</text>  
            </view>  
            <view class="uni-common-mt">  
                <slider class="slider" min="0" max="21" step="1" :value="playTime" @change="seek"></slider>  
            </view>  
            <view class="play-time">  
                <text>00:00</text>  
                <text>00:21</text>  
            </view>  
            <view class="uni-hello-text">注意：离开当前页面后背景音乐将保持播放，但退出uni-app将停止</view>  
            <view class="page-body-buttons">  
                <block v-if="playing">  
                    <view class="page-body-button" @tap="stop">  
                        <image src="/static/stop.png"></image>  
                    </view>  
                    <view class="page-body-button" @tap="pause">  
                        <image src="/static/pause.png"></image>  
                    </view>  
                </block>  
                <block v-if="!playing">  
                    <view class="page-body-button"></view>  
                    <view class="page-body-button" @tap="play">  
                        <image src="/static/play.png"></image>  
                    </view>  
                </block>  
                <view class="page-body-button"></view>  
            </view>  
            <button @click="next">下一曲</button>  
        </view>  
    </view>  
</template>  
<script>  

    var util = require('../../../common/util.js');  

    export default {  
        data() {  
            return {  
                title: 'backgroundAudio',  
                bgAudioMannager: null,  
                dataUrl: 'https://vkceyugu.cdn.bspapp.com/VKCEYUGU-hello-uniapp/2cc220e0-c27a-11ea-9dfb-6da8e309e0d8.mp3',  
                playing: false,  
                playTime: 0,  
                formatedPlayTime: '00:00:00'  
            }  
        },  
        onLoad: function () {  
            this.playing = this.$backgroundAudioData.playing;  
            this.playTime = this.$backgroundAudioData.playTime;  
            this.formatedPlayTime = this.$backgroundAudioData.formatedPlayTime;  

            let bgAudioMannager = uni.getBackgroundAudioManager();  
            if(!bgAudioMannager.title){  
                bgAudioMannager.title = '致爱丽丝';  
            }  
            if(!bgAudioMannager.singer) {  
                bgAudioMannager.singer = '暂无';  
            }  
            if(!bgAudioMannager.coverImgUrl){  
                bgAudioMannager.coverImgUrl = 'https://img-cdn-qiniu.dcloud.net.cn/uniapp/audio/music.jpg';  
            }  

            bgAudioMannager.onPlay(() => {  
                console.log("开始播放");  
                this.$backgroundAudioData.playing = this.playing = true;  
            })  
            bgAudioMannager.onPause(() => {  
                console.log("暂停播放");  
                this.$backgroundAudioData.playing = this.playing = false;  
            })  
            bgAudioMannager.onEnded(() => {  
                this.playing = false;  
                this.$backgroundAudioData.playing = false;  
                this.$backgroundAudioData.playTime = this.playTime = 0;  
                this.$backgroundAudioData.formatedPlayTime = this.formatedPlayTime = util.formatTime(0);  
            })  

            bgAudioMannager.onTimeUpdate((e) => {  
                if (Math.floor(bgAudioMannager.currentTime) > Math.floor(this.playTime)) {  
                    this.$backgroundAudioData.formatedPlayTime = this.formatedPlayTime = util.formatTime(Math.floor(bgAudioMannager.currentTime));  
                }  
                this.$backgroundAudioData.playTime = this.playTime = bgAudioMannager.currentTime;  
            })  

            this.bgAudioMannager = bgAudioMannager;  
        },  
        methods: {  
            play: function (res) {  
                if (!this.bgAudioMannager.src) {  
                    this.bgAudioMannager.startTime = this.playTime;  
                    this.bgAudioMannager.src = this.dataUrl;  
                } else {  
                    this.bgAudioMannager.seek(this.playTime);  
                    this.bgAudioMannager.play();  
                }  
            },  
            seek: function (e) {  
                this.bgAudioMannager.seek(e.detail.value);  
            },  
            pause: function () {  
                this.bgAudioMannager.pause();  
            },  
            stop: function () {  
                this.bgAudioMannager.stop();  
                this.$backgroundAudioData.playing = this.playing = false;  
                this.$backgroundAudioData.playTime = this.playTime = 0;  
                this.$backgroundAudioData.formatedPlayTime = this.formatedPlayTime = util.formatTime(0);  
            },  
            next(){  
                this.bgAudioMannager.src="https://moyu.aitekapp.com/song/c1d00fd9a7fd71c0ef669d3fa57acf74.mp3"  
            }  
        }  
    }  
</script>  

<style>  
    image {  
        width: 150rpx;  
        height: 150rpx;  
    }  

    .page-body-text {  
        padding: 0 30rpx;  
    }  

    .page-body-wrapper {  
        margin-top: 0;  
    }  

    .page-body-info {  
        padding-bottom: 50rpx;  
    }  

    .time-big {  
        font-size: 60rpx;  
        margin: 20rpx;  
    }  

    .slider {  
        width:630rpx;  
    }  

    .play-time {  
        font-size: 28rpx;  
        width:100%;  
        padding: 20rpx 0;  
        display: flex;  
        justify-content: space-between;  
        box-sizing: border-box;  
    }  

    .page-body-buttons {  
        display: flex;  
        justify-content: space-around;  
        margin-top: 100rpx;  
    }  

    .page-body-button {  
        width: 250rpx;  
        text-align: center;  
    }  
</style>