Reader Level:
Article

Media Playlist in Windows Store Apps

By Deepak Middha on Oct 11, 2012
In this app I described how to create and save a media playlist in a Windows Store App using JavaScript.

Introduction

Today we are going to learn how to create a Windows Store App for a media playlist using JavaScript. This app will create and save a playlist from a set of audio files by giving the appropriate locations.

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 two JavaScript pages 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.

mediaplaylist-Windows-store-apps.jpg


Write the following code in default.html:

<!DOCTYPE html>

<html>

<head>

    <meta charset="utf-8" />

    <title>Media 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:gainsboro">

    <center><div id="rootGrid">

        <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 = "Playlists app";

 

    var pages = [

        { url: "page.html" }

    ];

 

    var audioExtensions = [".wma", ".mp3", ".mp2", ".aac", ".adt", ".adts", ".m4a"];

    var playlistExtensions = [".m3u", ".wpl", ".zpl"];

    var playlist = null;

 

    var ensureUnsnapped = function () {

        var success = true;

        if (Windows.UI.ViewManagement.ApplicationView.value === Windows.UI.ViewManagement.ApplicationViewState.snapped) {

            success = Windows.UI.ViewManagement.ApplicationView.tryUnsnap();

        }

 

        if (!success) {

            WinJS.log && WinJS.log("Unable to unsnap the app.", "app", "error");

        }

 

        return success;

    };

 

    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,

        audioExtensions: audioExtensions,

        playlistExtensions: playlistExtensions,

        playlist: playlist,

        ensureUnsnapped: ensureUnsnapped

    });

 

    WinJS.Application.addEventListener("activated", activated, false);

    WinJS.Application.start();

})();


Write the following code in page.html:
 

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">

<head>

    <title>Create</title>

    <script src="/js/script.js"></script>

</head>

<body>

    <div data-win-control="App.pageInput">

        <button id="PickAudioButton">Pick audio</button>

    </div>

    <div data-win-control="App.pageOutput">

    </div>

</body>

</html> 


Write the following code in script.js:
 

(function () {

    "use strict";

    var page = WinJS.UI.Pages.define("page.html", {

        ready: function (element, options) {

            document.getElementById("PickAudioButton").addEventListener("click", pickAudio, false);

        }

    });

 

    function pickAudio() {

        if (!App.ensureUnsnapped()) {

            return;

        }

 

        var picker = new Windows.Storage.Pickers.FileOpenPicker();

        picker.suggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.musicLibrary;

        picker.fileTypeFilter.replaceAll(App.audioExtensions);

 

        picker.pickMultipleFilesAsync()

            .done(function (files) {

                if (files.size > 0) {

                    App.playlist = new Windows.Media.Playlists.Playlist();

 

                    files.forEach(function (file) {

                        App.playlist.files.append(file);

                    });

 

                    App.playlist.saveAsAsync(Windows.Storage.KnownFolders.musicLibrary,

                                                   "app",

                                                   Windows.Storage.NameCollisionOption.replaceExisting,

                                                   Windows.Media.Playlists.PlaylistFormat.windowsMedia)

                        .done(function (file) {

                            WinJS.log && WinJS.log(file.name + " was created and saved with " + App.playlist.files.size + " files.", "app", "status");

                            App.playlist = null;

                        }, function (error) {

                            WinJS.log && WinJS.log(error, "app", "error");

                        });

                }

                else {

                    WinJS.log && WinJS.log("No files picked.", "app", "error");

                }

            }, function (error) {

                WinJS.log && WinJS.log(error, "app", "error");

            });

    }

})(); 


Write the following code in script1.js:
 

(function () {

 

    var pageOutput = WinJS.Class.define(

        function (element, options) {

            element.winControl = this;

            this.element = element;

            new WinJS.Utilities.QueryCollection(element)

                        .setAttribute("role", "region")

                        .setAttribute("aria-labelledby", "outputLabel")

                        .setAttribute("aria-live", "assertive");

            element.id = "output";

 

            this._addOutputLabel(element);

            this._addStatusOutput(element);

        }, {

            _addOutputLabel: function (element) {

                var label = document.createElement("h2");

                label.id = "outputLabel";

                label.textContent = "";

                element.parentNode.insertBefore(label, element);

            },

            _addStatusOutput: function (element) {

                var statusDiv = document.createElement("div");

                statusDiv.id = "statusMessage";

                element.insertBefore(statusDiv, element.childNodes[0]);

            }

        }

    );

    var currentpageUrl = null;

    WinJS.log = function (message, tag, type) {

        var statusDiv = document.getElementById("statusMessage");

    };

    function activated(e) {

        WinJS.Utilities.query("#featureLabel")[0].textContent = App.appTitle;

    }

 

    WinJS.Application.addEventListener("activated", activated, false);

    WinJS.Namespace.define("App", {

        pageOutput: pageOutput

    });

})(); 


Output:

playlist-in-indows-store-apps.jpg

Summary

In this app I described how to create and save a media playlist in a Windows Store App using JavaScript. I hope this article has helped you to understand this topic. Please share it if you know more about this. Your feedback and constructive contributions are welcome.

Deepak Middha

Deepak Middha is one time Microsoft MVP(Client App Dev) , working as Sr. Software Developer with lots of hands on experience using ASP.NET 2.0/3.5, AJAX, MVC, C#,  SQL Server 2005/2008/2012, WCF, JQuery and Silverl... Read more

COMMENT USING