Introduction
In this article I describe how to create a Windows Store App for a Media event using JavaScript. This scenario demonstrates how to register for media events from hardware media transport controls
I assume you can create a simple Windows Store App using JavaScript. For more help visit Simple Windows Store Apps using JavaScript.
To start the creation of the app, add one JavaScript page by right-clicking on the js folder in the Solution Explorer and select Add > new item > JavaScript Page and then give an appropriate name. In the same way, add one HTML page to your project.
Write the following code in default.html:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>app</title>
<link rel="stylesheet" href="//Microsoft.WinJS.1.0/css/ui-light.css" />
<script src="//Microsoft.WinJS.1.0/js/base.js"></script>
<script src="//Microsoft.WinJS.1.0/js/ui.js"></script>
<link rel="stylesheet" href="/css/default.css" />
<script src="/js/script1.js"></script>
<script src="/js/default.js"></script>
</head>
<body role="application" style="background-color: lightgrey">
<div id="rootGrid">
<center><div id="content">
<h1 id="featureLabel"></h1>
<div id="contentHost"></div>
</div>
</div>
</center>
</body>
</html>
Write the following code in default.js:
(function () {
"use strict";
var appTitle = "";
var pages = [
{ url: "page.html" }
];
function activated(eventObject) {
if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) {
eventObject.setPromise(WinJS.UI.processAll().then(function () {
var url = WinJS.Application.sessionState.lastUrl || pages[0].url;
return WinJS.Navigation.navigate(url);
}));
}
}
WinJS.Navigation.addEventListener("navigated", function (eventObject) {
var url = eventObject.detail.location;
var host = document.getElementById("contentHost");
host.winControl && host.winControl.unload && host.winControl.unload();
WinJS.Utilities.empty(host);
eventObject.detail.setPromise(WinJS.UI.Pages.render(url, host, eventObject.detail.state).then(function () {
WinJS.Application.sessionState.lastUrl = url;
}));
});
WinJS.Namespace.define("App", {
appTitle: appTitle,
pages: pages
});
WinJS.Application.addEventListener("activated", activated, false);
WinJS.Application.start();
})();
Write the following code in page.html:
<!DOCTYPE html>
<html>
<head>
<title></title>
<link rel="stylesheet" href="/css/page1.css" />
<script src="/js/script.js"></script>
</head>
<body>
<div data-win-control="App.pageInput">
<button id="button1">Select</button>
<br />
<br />
</div>
<div data-win-control="App.pageOutput">
<audio id="audiotag" controls="controls" msaudiocategory="backgroundcapablemedia" />
<img id="albumart" />
</div>
</body>
</html>
Write the following code in script.js:
(function () {
"use strict";
var mediaControls;
var currentSongIndex = 0;
var playlist = [];
var playlistCount;
var nextRegistered = false;
var previousRegistered = false;
var thumbnailName = null;
function song() {
this.URLObject;
this.file;
}
var page = WinJS.UI.Pages.define("page.html", {
ready: function (element, options) {
document.getElementById("button1").addEventListener("click", doSomething1, false);
mediaControls = Windows.Media.MediaControl;
mediaControls.addEventListener("playpausetogglepressed", playPause, false);
mediaControls.addEventListener("playpressed", play, false);
mediaControls.addEventListener("stoppressed", stop, false);
mediaControls.addEventListener("pausepressed", pause, false);
mediaControls.addEventListener("fastforwardpressed", fastForward, false);
mediaControls.addEventListener("rewindpressed", rewind, false);
mediaControls.addEventListener("channeluppressed", channelUp, false);
mediaControls.addEventListener("channeldownpressed", channelDown, false);
mediaControls.addEventListener("recordpressed", record, false);
id("audiotag").addEventListener("playing", playing, false);
id("audiotag").addEventListener("pause", paused, false);
id("audiotag").addEventListener("ended", songEnded, false);
mediaControls.isPlaying = false;
}
});
function id(elementId) {
return document.getElementById(elementId);
}
function createPlaylist(files) {
var file;
if (files.size > 0) {
playlistCount = files.size;
if (nextRegistered) {
mediaControls.removeEventListener("nexttrackpressed", nextTrack, false);
nextRegistered = false;
}
if (previousRegistered) {
mediaControls.removeEventListener("previoustrackpressed", previousTrack, false);
previousRegistered = false;
}
currentSongIndex = 0;
playlist = [];
if (playlistCount > 1) {
if (!nextRegistered) {
mediaControls.addEventListener("nexttrackpressed", nextTrack, false);
nextRegistered = true;
}
}
for (var fileIndex = 0; fileIndex < files.size; fileIndex++) {
var tempSong = new song;
file = files[fileIndex];
tempSong.URLObject = URL.createObjectURL(file, { oneTimeOnly: false });
tempSong.file = file;
playlist[fileIndex] = tempSong;
}
}
}
function setCurrentPlaying(index) {
id("audiotag").src = playlist[index].URLObject;
if (mediaControls.isPlaying === true) {
id("audiotag").play();
}
setMetaData(index);
}
function setMetaData(songIndex) {
try {
var thumbnailMode = Windows.Storage.FileProperties.ThumbnailMode.musicView;
var thumbnailOptions = Windows.Storage.FileProperties.ThumbnailOptions.ResizeThumbnail;
var file = playlist[songIndex].file;
file.getThumbnailAsync(thumbnailMode, 96, thumbnailOptions).done(function (thumbnail) {
if (thumbnail) {
var inputStream = thumbnail.getInputStreamAt(0);
var reader = new Windows.Storage.Streams.DataReader(inputStream);
var size = thumbnail.size;
if (size > 0) {
reader.loadAsync(size).done(function () {
var buffer = new Array(size);
reader.readBytes(buffer);
thumbnail.close();
reader.close();
var tempFolder = Windows.Storage.ApplicationData.current.temporaryFolder;
if (thumbnailName === null || thumbnailName === "thumbnail2.jpg") {
thumbnailName = "thumbnail.jpg";
} else {
thumbnailName = "thumbnail2.jpg";
}
tempFolder.createFileAsync(thumbnailName, Windows.Storage.CreationCollisionOption.replaceExisting).done(function (imageFile) {
Windows.Storage.FileIO.writeBytesAsync(imageFile, buffer).done(function () {
playlist[songIndex].file.properties.getMusicPropertiesAsync().done(function (musicProperties) {
setAlbumArt(thumbnailName, musicProperties);
});
});
});
});
} else {
WinJS.log("Thumbnail is empty", "app", "error");
thumbnail.close();
reader.close();
inputStream.close();
}
} else {
WinJS.log(getTimeStampedMessage("Song Art Work not available for " + storageFile.path), "app", "error");
mediaControls.albumArt = "";
}
});
} catch (ex) {
WinJS.log("Error in GetThumbnail(): " + ex.description, "app", "error");
}
}
function setAlbumArt(fileName, musicProperties) {
try {
var uri = new Windows.Foundation.Uri("ms-appdata:///temp/" + fileName);
mediaControls.albumArt = uri;
mediaControls.trackName = musicProperties.title;
mediaControls.artistName = musicProperties.artist;
} catch (ex) {
WinJS.log("Error in setAlbumArt(): " + ex, "app", "error");
}
}
function doSomething1() {
var openPicker = new Windows.Storage.Pickers.FileOpenPicker();
openPicker.fileTypeFilter.replaceAll([".mp3", ".mp4", ".wma", ".m4a"]);
openPicker.suggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.musicLibrary;
openPicker.pickMultipleFilesAsync().done(function (files) {
if (files.length > 0) {
createPlaylist(files);
setCurrentPlaying(currentSongIndex);
}
});
}
function getTimeStampedMessage(eventCalled) {
var timeformat = new Windows.Globalization.DateTimeFormatting.DateTimeFormatter("longtime");
var time = timeformat.format(new Date());
var message = eventCalled + "\t\t" + time;
return message;
}
function playing() {
mediaControls.isPlaying = true;
}
function paused() {
mediaControls.isPlaying = false;
}
function songEnded() {
nextTrack();
}
function playPause() {
if (mediaControls.isPlaying === false) {
WinJS.log(getTimeStampedMessage("Play/Pause - Play Received"), "app", "status");
id("audiotag").play();
}
else {
WinJS.log(getTimeStampedMessage("Play/Pause - Pause Received"), "app", "status");
id("audiotag").pause();
}
}
function play() {
WinJS.log(getTimeStampedMessage("Play Received"), "app", "status");
id("audiotag").play();
}
function stop() {
WinJS.log(getTimeStampedMessage("Stop Received"), "app", "status");
id("audiotag").pause();
id("audiotag").currentTime = 0;
}
function pause() {
WinJS.log(getTimeStampedMessage("Pause Received"), "app", "status");
id("audiotag").pause();
}
function nextTrack() {
WinJS.log(getTimeStampedMessage("Next Track Received"), "app", "status");
if (currentSongIndex < (playlistCount - 1)) {
currentSongIndex++;
setCurrentPlaying(currentSongIndex);
if (currentSongIndex > 0) {
if (!previousRegistered) {
mediaControls.addEventListener("previoustrackpressed", previousTrack, false);
previousRegistered = true;
}
}
if (currentSongIndex === (playlistCount - 1)) {
if (nextRegistered) {
mediaControls.removeEventListener("nexttrackpressed", nextTrack, false);
nextRegistered = false;
}
}
}
}
function previousTrack() {
WinJS.log(getTimeStampedMessage("Prev Track Received"), "app", "status");
if (currentSongIndex > 0) {
if (currentSongIndex === (playlistCount - 1)) {
if (!nextRegistered) {
mediaControls.addEventListener("nexttrackpressed", nextTrack, false);
nextRegistered = true;
}
}
currentSongIndex--;
if (currentSongIndex === 0) {
if (previousRegistered) {
mediaControls.removeEventListener("previoustrackpressed", previousTrack, false);
previousRegistered = false;
}
}
setCurrentPlaying(currentSongIndex);
}
}
function fastForward() {
WinJS.log(getTimeStampedMessage("Fast Forward Received"), "app", "status");
}
function rewind() {
WinJS.log(getTimeStampedMessage("Rewind Received"), "app", "status");
}
function channelUp() {
WinJS.log(getTimeStampedMessage("Channel Up Received"), "app", "status");
}
function channelDown() {
WinJS.log(getTimeStampedMessage("Channel Down Received"), "app", "status");
}
function record() {
WinJS.log(getTimeStampedMessage("Record Received"), "app", "status");
}
})();
Output:
![camer-function-in-windows-store-apps.jpg]()
Summary
In this app I described Media events in Windows Store Apps using JavaScript. I hope this article has helped you to understand this topic. Please share if you know more about this. Your feedback and constructive contributions are welcome.