如何在JavaScript中播放和暂停音频源节点的单个按钮（index.php中将显示按钮）？
所以基本上你有一个播放音频的按钮，当再次点击时，它会暂停歌曲...... 编辑：index.php
<!DOCTYPE html>
<html>
<head>
<meta name="description" content="HTML5 Audio Spectrum Visualizer">
<title>HTML5 Audio API showcase | Audio visualizer</title>
<link type="text/css" rel="stylesheet" href="style/style.css">
</head>
<body>
<div id="wrapper">
<div id="fileWrapper" class="file_wrapper">
<div id="info">
HTML5 Audio API showcase | An Audio Viusalizer
</div>
<label for="uploadedFile">Drag&drop or select a file to play:
</label>
<input type="file" id="uploadedFile"></input>
</div>
<div id="visualizer_wrapper">
<canvas id='canvas' width="800" height="350"></canvas>
</div>
</div>
<footer>
<small></small>
</footer>
<script type="text/javascript" src="js/html5_audio_visualizer.js">
</script>
</body>
</html>
以下是JavaScript代码的一部分：
window.onload = function() {
new Visualizer().ini();
};
var Visualizer = function() {
this.file = null; //the current file
this.fileName = null; //the current file name
this.audioContext = null;
this.source = null; //the audio source
this.info = document.getElementById('info').innerHTML; //this used to
upgrade the UI information
this.infoUpdateId = null; //to sotore the setTimeout ID and clear the
interval
this.animationId = null;
this.status = 0; //flag for sound is playing 1 or stopped 0
this.forceStop = false;
this.allCapsReachBottom = false;
}
Visualizer.prototype = {
ini: function() {
this._prepareAPI();
this._addEventListner();
},
_prepareAPI: function() {
//fix browser vender for AudioContext and requestAnimationFrame
window.AudioContext = window.AudioContext || window.webkitAudioContext
|| window.mozAudioContext || window.msAudioContext;
window.requestAnimationFrame = window.requestAnimationFrame ||
window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame ||
window.msRequestAnimationFrame;
window.cancelAnimationFrame = window.cancelAnimationFrame ||
window.webkitCancelAnimationFrame || window.mozCancelAnimationFrame ||
window.msCancelAnimationFrame;
try {
this.audioContext = new AudioContext();
} catch (e) {
this._updateInfo('!Your browser does not support AudioContext',
false);
console.log(e);
}
},
_addEventListner: function() {
var that = this,
audioInput = document.getElementById('uploadedFile'),
dropContainer = document.getElementsByTagName("canvas")[0];
//listen the file upload
audioInput.onchange = function() {
if (that.audioContext===null) {return;};
//the if statement fixes the file selction cancle, because the
onchange will trigger even the file selection been canceled
if (audioInput.files.length !== 0) {
//only process the first file
that.file = audioInput.files[0];
that.fileName = that.file.name;
if (that.status === 1) {
//the sound is still playing but we upload another file, so
set the forceStop flag to true
that.forceStop = true;
};
document.getElementById('fileWrapper').style.opacity = 1;
that._updateInfo('Uploading', true);
//once the file is ready,start the visualizer
that._start();
};
};
//listen the drag & drop
dropContainer.addEventListener("dragenter", function() {
document.getElementById('fileWrapper').style.opacity = 1;
that._updateInfo('Drop it on the page', true);
}, false);
dropContainer.addEventListener("dragover", function(e) {
e.stopPropagation();
e.preventDefault();
//set the drop mode
e.dataTransfer.dropEffect = 'copy';
}, false);
dropContainer.addEventListener("dragleave", function() {
document.getElementById('fileWrapper').style.opacity = 0.2;
that._updateInfo(that.info, false);
}, false);
dropContainer.addEventListener("drop", function(e) {
e.stopPropagation();
e.preventDefault();
if (that.audioContext===null) {return;};
document.getElementById('fileWrapper').style.opacity = 1;
that._updateInfo('Uploading', true);
//get the dropped file
that.file = e.dataTransfer.files[0];
if (that.status === 1) {
document.getElementById('fileWrapper').style.opacity = 1;
that.forceStop = true;
};
that.fileName = that.file.name;
//once the file is ready,start the visualizer
that._start();
}, false);
},
_start: function() {
//read and decode the file into audio array buffer
var that = this,
file = this.file,
fr = new FileReader();
fr.onload = function(e) {
var fileResult = e.target.result;
var audioContext = that.audioContext;
if (audioContext === null) {
return;
};
that._updateInfo('Decoding the audio', true);
audioContext.decodeAudioData(fileResult, function(buffer) {
that._updateInfo('Decode succussfully,start the visualizer',
true);
that._visualize(audioContext, buffer);
}, function(e) {
that._updateInfo('!Fail to decode the file', false);
console.log(e);
});
};
fr.onerror = function(e) {
that._updateInfo('!Fail to read the file', false);
console.log(e);
};
//assign the file to the reader
this._updateInfo('Starting read the file', true);
fr.readAsArrayBuffer(file);
},
_visualize: function(audioContext, buffer) {
var audioBufferSouceNode = audioContext.createBufferSource(),
analyser = audioContext.createAnalyser(),
that = this;
//connect the source to the analyser
audioBufferSouceNode.connect(analyser);
//connect the analyser to the destination(the speaker), or we won't
hear the sound
analyser.connect(audioContext.destination);
//then assign the buffer to the buffer source node
audioBufferSouceNode.buffer = buffer;
//play the source
if (!audioBufferSouceNode.start) {
audioBufferSouceNode.start = audioBufferSouceNode.noteOn //in old
browsers use noteOn method
audioBufferSouceNode.stop = audioBufferSouceNode.noteOff //in old
browsers use noteOn method
};
//stop the previous sound if any
if (this.animationId !== null) {
cancelAnimationFrame(this.animationId);
}
if (this.source !== null) {
this.source.stop(0);
}
audioBufferSouceNode.start(0);
this.status = 1;
this.source = audioBufferSouceNode;
audioBufferSouceNode.onended = function() {
that._audioEnd(that);
};
this._updateInfo('Playing ' + this.fileName, false);
this.info = 'Playing ' + this.fileName;
document.getElementById('fileWrapper').style.opacity = 0.2;
this._drawSpectrum(analyser);
},
...
我该怎么做呢？还可以创建基本音量滑块吗？