一、所涉及到的相关知识应用：
1.ajax 的使用；
2.DOM 的操作；
3.关于事件相关的一些操作；
4.音乐相关 api 的使用。
二、整理核心点逻辑，并对功能有一定认识：
1. 音乐从哪里来：
比如说歌曲的数据可以放在一个数组里面，直接去用；也可以通过从服务端去获取，使用 ajax 去获取数据。
获取到之后就得到一个音乐的数据，一个数组。我们得到的音乐数据应该包括：音乐标题、作者、背景图片、音乐地址。
2. 如何去操作播放音乐：
比如我有了一个音乐地址，应该如何去播放？音量我能不能控制？播放过程中播放了多少时间我能不能得到，能不能去暂停它？
这些即我们需要的功能，或者说技术关键点。
3. 如何把他们组装起来。
比如把音乐播放器放在页面上，然后结合事件，当点击按钮时再执行对应具体操作。
三、. 音乐播放器
1. API
1. audioObject
创建或者获取的 audio 对象，可通过以下两种方式得到：
方法一：
<audio id="music" src="http://cloud.hunger-valley.com/music/玫瑰.mp3">你的浏览器不支持喔！</audio>
<script>
var audioObject = document.querySelector('#music')
</script>
方法二：
var audioObject = new Audio('http://cloud.hunger-valley.com/music/玫瑰.mp3')
2. audioObject.play()
开始播放
3. audioObject.pause()
暂停播放
4. audioObject.autoplay()
设置或者获取自动播放状态：
audioObject.autoPlay = true //设置为自动播放，下次更换 audioObject.src 后会自动播放音乐
audioObject.autoPlay = false //设置不自动播放
console.log(audioObject.autoPlay)
5. audioObject.src
设置或者获取音乐地址：
audioObject.src = "http://cloud.hunger-valley.com/music/ifyou.mp3"
console.log(audioObject.src)
6. audioObject.volume
设置或者获取音量，最大值为 1，0 为静音：
audioObject.volume = 0.5
audioObject.volume = 1
console.log(audioObject.volume)
7. audioObject.loop
设置或者获取循环状态：
audioObject.loop = true
console.log(audioObject.loop)
8. audioObject.duration
获取音乐长度，单位为秒：
console.log(audioObject.duration)
9. audioObject.currentTime
设置或者获取播放时间：
console.log(audioObject.currentTime)
10. audioObject.ended
判断音乐是否播放完毕，只读属性。
2. 事件
1. playing
当音乐开始播放，暂停后重新开始播放，设置 currenTime 后开始播放时触发：
audioObject.addEventListener('playing', function(){
console.log('playing')
})
2. pause
当音乐暂停时和结束时触发：
audioObject.addEventListener('pause', function(){
console.log('pause')
})
3. ended
当音乐结束时触发：
audioObject.addEventListener('ended', function(){
console.log('ended')
})
4. timeupdate
当 currentTime 更新时会触发 timeupdate 事件，这个事件的触发频率由系统决定，但是会保证每秒触发 4-66 次（前提是每次事件处理不会超过250ms）：
//如下代码设置 每1秒左右执行一次
audioObject.shouldUpdate = true
audioObject.ontimeupdate = function(){
var _this = this
if(_this.shouldUpdate) {
//do something
console.log('update')
_this.shouldUpdate = false
setTimeout(function(){
_this.shouldUpdate = true
}, 1000)
}
}
5. volumechange
当音量改变时触发：
audioObject.onvolumechange = function(){
console.log('volumechage')
})
整合后的代码：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>音乐播放器</title>
<link rel="stylesheet" href="http://at.alicdn.com/t/font_881589_c0dwmabq02l.css">
<style>
/* reset.css */
* {
margin: 0;
padding: 0;
}
/* common.css */
body {
height: 100vh;
}
.cover {
position: absolute;
content: '';
display: block;
width: 100%;
height: 100%;
background: url(http://cloud.hunger-valley.com/17-9-22/87786461.jpg) center center no-repeat;
background-size: cover;
filter: blur(3px);
}
/* index.css */
.musicbox {
position: absolute;
left: 50%;
top: 40%;
transform: translate(-50%, -50%);
font-family: cursive;
font-size: 16px;
color: #f06d6a;
width: 340px;
}
.music-panel {
border: 1px solid #76dba3;
padding: 20px 20px 5px 20px;
box-shadow: 0px 2px 5px 0px rgba(0,0,0,.1), 0px 2px 10px 0px rgba(0,0,0,.05);
background-color: rgba(255,255,255,.9);
}
.musicbox .control {
margin-top: 20px;
font-size: 22px;
color: #ee8a87;
float: left;
}
.musicbox .control .iconfont {
margin-right: 12px;
cursor: pointer;
}
.musicbox .control .iconfont.disable {
opacity: 0.3;
}
.musicbox .info {
margin-left: 120px;
}
.musicbox .info .title {
font-size: 18px;
}
.musicbox .info .author {
font-size: 13px;
}
.musicbox .progress {
width: 260px;
}
.musicbox .progress .bar {
height: 3px;
margin-top: 5px;
background-color: rgba(0,0,0,.2);
cursor: pointer;
}
.musicbox .progress .progress-now {
height: 2px;
width: 0;
background-color: #ee8a87;
position: relative;
}
.musicbox .time {
text-align: right;
}
.musicbox:after,
.musicbox .music:after {
content: '';
display: block;
clear: both;
}
.musicbox .list {
list-style: none;
}
.musicbox .list>li {
position: relative;
padding: 4px 10px;
border: 1px solid rgba(255,255,255,.8);
border-top: none;
overflow: hidden;
cursor: pointer;
background-color: rgba(0,0,0,.8);
}
.musicbox .list>li:hover {
background-color: rgba(255,255,255,.5);
}
.musicbox .list>li.playing:before {
position: absolute;
top: 0;
left: 0;
content: '';
display: inline-block;
width: 8px;
height: 30px;
background: rgba(255,255,255,.8);
}
</style>
</head>
<body>
<!-- index.html -->
<div class="cover"></div>
<div class="musicbox">
<div class="music-panel">
<div class="music">
<div class="control">
<span class="back"><i class=" iconfont icon-back"></i></span>
<span class="play"><i class=" iconfont icon-play"></i></span>
<span class="forward"><i class=" iconfont icon-forward"></i></span>
</div>
<div class="info">
<div class="title">My Song</div>
<div class="author">Jay</div>
</div>
</div>
<div class="progress">
<div class="bar">
<div class="progress-total"></div>
<div class="progress-now"></div>
</div>
<div class="time">0:00</div>
</div>
<ul class="list">
<li>贰佰-玫瑰</li>
<li>IF YOU-Big Bang</li>
</ul>
</div>
</div>
<script>
// index.js
// function $(selector){
// return document.querySelector(selector);
// }
// var musicList = [];
// var currentIndex = 0;
// var clock;
// var audio = new Audio();
// audio.autoplay = true;
// getMusicList(function(list){
// musicList = list;
// loadMusic(list[currentIndex]);
// generateList(list);
// });
// audio.ontimeupdate = function(){
// $('.musicbox .progress-now').style.width = (this.currentTime/this.duration)*100 + '%';
// };
// audio.onplay = function(){
// clock =setInterval(function(){
// var min = Math.floor(audio.currentTime/60);
// var sec = Math.floor(audio.currentTime%60) + '';
// sec = sec.length ===2? sec : '0' + sec;
// $('.musicbox .time').innerText = min + ':' +sec;
// }, 1000);
// };
// audio.onpause = function(){
// clearInterval(clock);
// };
// audio.onended = function(){
// concole.log('end');
// currentIndex = (++currentIndex)%musicList.length;
// loadMusic(musicList[currentIndex]);
// };
// $('.musicbox .play').onclick = function(){
// if(audio.paused){
// audio.play();
// this.querySelector('.iconfont').classList.remove('icon-play');
// this.querySelector('.iconfont').classList.add('icon-pause');
// }else {
// audio.pause();
// this.querySelector('.iconfont').classList.add('icon-play');
// this.querySelector('.iconfont').classList.remove('icon-pause');
// }
// };
// $('.musicbox .forward').onclick = function(){
// currentIndex = (++currentIndex)%musicList.length;
// loadMusic(musicList[currentIndex]);
// };
// $('.musicbox .back').onclick = function(){
// currentIndex = (musicList.length + --currentIndex)%musicList.length;
// loadMusic(musicList[currentIndex]);
// };
// $('.music .bar').onclik = function(e){
// console.log(e);
// var percent = e.offsetX / parseInt(getComputedStyle(this).width);
// console.log(percent);
// audio.currentTime = audio.duration * percent;
// };
// function getMusicList(callback){
// var xhr = new XMLHttpRequest();
// xhr.open('Get', '/music.json', true);
// xhr.onload = function(){
// if((xhr.status >= 200 && xhr.status < 300) || xhr.status === 304){
// callback(JSON.parse(this.responseText));
// }else {
// console.log('获取数据失败');
// }
// };
// xhr.onerror = function(){
// console.log('网络异常');
// };
// xhr.send();
// }
// function loadMusic(musicObj){
// console.log('begin play', musicObj);
// $('.musicbox .title').innerText = musicObj.title;
// $('.musicbox .author').innerText = musicObj.author;
// $('.cover').style.backgroundImage = 'url(' + musciObj.img + ')';
// audio.src = musicObj.src;
// }
var musicList = [
{
src: 'http://cloud.hunger-valley.com/music/玫瑰.mp3',
title: '玫瑰',
author: '贰佰',
img: 'https://upload-images.jianshu.io/upload_images/3624093-d9678a0d2a897390.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240'
},
{
src: 'http://cloud.hunger-valley.com/music/ifyou.mp3',
title: 'IF YOU',
author: 'Big Bang',
img: 'https://upload-images.jianshu.io/upload_images/3624093-84598b108b24d414.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240'
}
];
var cover = document.querySelector('.cover');
var backBtn = document.querySelector('.musicbox .back');
var playBtn = document.querySelector('.musicbox .play');
var forwardBtn = document.querySelector('.musicbox .forward');
var titleNode = document.querySelector('.musicbox .title');
var authorNode = document.querySelector('.musicbox .author');
var timeNode = document.querySelector('.musicbox .time');
var progressBarNode = document.querySelector('.musicbox .progress .bar');
var progressNowNode = document.querySelector('.musicbox .progress-now');
var musicListContainer = document.querySelector('.musicbox .list');
var timer;
var musicList;
var music = new Audio();
music.autoplay = true;
var musicIndex = 0;
getMusic(function(list){
musicList = list;
setPlaylist(list);
loadMusic(list[musicIndex]);
});
playBtn.onclick = function() {
var icon = this.querySelector('.iconfont');
if(icon.classList.contains('icon-play')) {
music.play();
}else {
music.pause();
}
icon.classList.toggle('icon-play');
icon.classList.toggle('icon-pause');
};
forwardBtn.onclick = loadNextMusic;
backBtn.onclick = loadLastMusic;
music.onended = loadNextMusic;
music.shouldUpdate = true;
music.onplaying = function() {
timer = setInterval(function() {
updateProgress();
}, 1000);
console.log('play');
};
music.onpause = function() {
console.log('pause');
clearInterval(timer);
};
music.ontimeupdate = updateProgress;
progressBarNode.onclick = function(e) {
var percent = e.offsetX / parseInt(getComputedStyle(this).width);
music.currentTime = percent * music.duration;
progressNowNode.style.width = percent *100 + "%";
};
musicListContainer.onclick = function(e) {
if(e.target.tagName.toLowerCase() === 'li'){
for(var i = 0; i < this.children.length; i++){
if(this.children[i] === e.target){
musicIndex = i;
}
}
console.log(musicIndex);
loadMusic(musicList[musicIndex]);
}
};
function setPlaylist(musiclist) {
var container = document.createDocumentFragment();
musiclist.forEach(function(musicObj){
var node = document.createElement('li');
node.innerText = musicObj.author + '-' + musicObj.title;
console.log(node);
container.appendChild(node);
});
musicListContainer.appendChild(container);
}
function loadMusic(songObj) {
music.src = songObj.src;
titleNode.innerText = songObj.title;
authorNode.innerText = songObj.author;
cover.style.backgroundImage = 'url(' + songObj.img + ')';
for(var i = 0; i < musicListContainer.children.length; i++){
musicListContainer.children[i].classList.remove('playing');
}
musicListContainer.children[musicIndex].classList.add('playing');
}
function loadNextMusic() {
musicIndex++;
musicIndex = musicIndex % musicList.length;
loadMusic(musicList[musicIndex]);
}
function loadLastMusic() {
musicIndex--;
musicIndex = (musicIndex + musicList.length) % musicList.length;
loadMusic(musicList[musicIndex]);
}
function updateProgress() {
var percent = (music.currentTime / music.duration) * 100 + '%';
progressNowNode.style.width = percent;
var minutes = parseInt(music.currentTime / 60);
var seconds = parseInt(music.currentTime % 60) + '';
seconds = seconds.length == 2 ? seconds : '0' + seconds;
timeNode.innerText = minutes + ':' + seconds;
}
function getMusic(callback) {
var xhr = new XMLHttpRequest();
xhr.open('get', 'music.json', true);
xhr.send();
xhr.onload = function() {
if((xhr.status >= 200 && xhr.status < 300) || xhr.status == 304) {
callback(JSON.parse(xhr.responseText));
}
};
}
</script>
</body>
</html>
