{"id":447,"date":"2021-10-22T18:56:06","date_gmt":"2021-10-22T18:56:06","guid":{"rendered":"https:\/\/www.louismarchand.me\/?page_id=447"},"modified":"2023-11-01T19:12:12","modified_gmt":"2023-11-01T19:12:12","slug":"android-acceder-aux-ressources-media","status":"publish","type":"page","link":"https:\/\/www.louismarchand.me\/index.php\/android-acceder-aux-ressources-media\/","title":{"rendered":"Acc\u00e9der aux ressources m\u00e9dia"},"content":{"rendered":"

Les \u00ab\u00a0contents providers\u00a0\u00bb<\/h2>\n

Le syst\u00e8me Android fournit un syst\u00e8me permettant le partage d’information entre diff\u00e9rentes applications. Cette fonctionnalit\u00e9 permet, par exemple, \u00e0 plusieurs applications d’effectuer du travail diff\u00e9rent en utilisant les m\u00eames donn\u00e9es. Android fournit cette fonctionnalit\u00e9 via le service de \u00ab\u00a0content provider\u00a0\u00bb. On peut acc\u00e9der au \u00ab\u00a0content provider\u00a0\u00bb \u00e0 partir de n’importe quel contexte Android (donc de n’importe quelle Activit\u00e9) en utilisant la fonction \u00ab\u00a0getContentResolver()\u00a0\u00bb.<\/p>\n

Les \u00ab\u00a0contents providers\u00a0\u00bb s’utilisent un peu comme une base de donn\u00e9es. On peut acc\u00e9der aux donn\u00e9es (query), ajouter des donn\u00e9es (insert), supprimer des donn\u00e9es (delete) ou modifier des donn\u00e9es (update). Voici des exemples:<\/p>\n

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    String<\/span>[]<\/span> mProjection<\/span> =<\/span>\r\n        {<\/span>\r\n            UserDictionary<\/span>.<\/span>Words<\/span>.<\/span>_ID<\/span>,<\/span>\r\n            UserDictionary<\/span>.<\/span>Words<\/span>.<\/span>WORD<\/span>,<\/span>\r\n            UserDictionary<\/span>.<\/span>Words<\/span>.<\/span>LOCALE<\/span>\r\n        };<\/span>\r\n\r\n    String<\/span> selectionClause<\/span> =<\/span> null<\/span>;<\/span>\r\n\r\n    String<\/span> sortOrder<\/span> =<\/span> null<\/span>;<\/span>\r\n\r\n    String<\/span>[]<\/span> selectionArgs<\/span> =<\/span> {<\/span>\"\"<\/span>};<\/span>\r\n\r\n    public<\/span> void<\/span> test<\/span>()<\/span> {<\/span>\r\n        Cursor<\/span> cursor<\/span> =<\/span> getContentResolver<\/span>().<\/span>query<\/span>(<\/span>UserDictionary<\/span>.<\/span>Words<\/span>.<\/span>CONTENT_URI<\/span>,<\/span>\r\n                    projection<\/span>,<\/span> selectionClause<\/span>,<\/span> selectionArgs<\/span>,<\/span> sortOrder<\/span>);<\/span>\r\n        boolean<\/span> contientProchain<\/span> =<\/span> cursor<\/span>.<\/span>moveToFirst<\/span>();<\/span>\r\n        while<\/span>(<\/span>contientProchain<\/span>){<\/span>\r\n            \/\/ Aller chercher les \u00e9l\u00e9ments avec cursor.get...<\/span>\r\n            contientProchain<\/span> =<\/span> cursor<\/span>.<\/span>moveToNext<\/span>();<\/span>\r\n        }<\/span>\r\n    }<\/span>\r\n<\/pre>\n<\/div>\n
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        ContentValues<\/span> nouvellesValeurs<\/span> =<\/span> new<\/span> ContentValues<\/span>();<\/span>\r\n        nouvellesValeurs<\/span>.<\/span>put<\/span>(<\/span>\"cle1\"<\/span>,<\/span> valeur1<\/span>)<\/span>\r\n        nouvellesValeurs<\/span>.<\/span>put<\/span>(<\/span>\"cle2\"<\/span>,<\/span> valeur2<\/span>)<\/span>\r\n        nouvellesValeurs<\/span>.<\/span>put<\/span>(<\/span>UserDictionary<\/span>.<\/span>Words<\/span>.<\/span>APP_ID<\/span>,<\/span> \"exemple.prog\"<\/span>);<\/span>\r\n        nouvellesValeurs<\/span>.<\/span>put<\/span>(<\/span>UserDictionary<\/span>.<\/span>Words<\/span>.<\/span>LOCALE<\/span>,<\/span> \"fr_CA\"<\/span>);<\/span>\r\n        nouvellesValeurs<\/span>.<\/span>put<\/span>(<\/span>UserDictionary<\/span>.<\/span>Words<\/span>.<\/span>WORD<\/span>,<\/span> \"mot\"<\/span>);<\/span>\r\n        \r\n        Uri<\/span> uri<\/span> =<\/span> getContentResolver<\/span>().<\/span>insert<\/span>(<\/span>\r\n            UserDictionary<\/span>.<\/span>Words<\/span>.<\/span>CONTENT_URI<\/span>,<\/span>\r\n            nouvellesValeurs<\/span>\r\n        );<\/span>\r\n<\/pre>\n<\/div>\n
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        ContentValues<\/span> updateValeurs<\/span> =<\/span> new<\/span> ContentValues<\/span>();<\/span>\r\n\r\n        String<\/span> selectionClause<\/span> =<\/span> UserDictionary<\/span>.<\/span>Words<\/span>.<\/span>LOCALE<\/span> +<\/span>  \" LIKE ?\"<\/span>;<\/span>\r\n        String<\/span>[]<\/span> selectionArgs<\/span> =<\/span> {<\/span>\"fr_%\"<\/span>};<\/span>\r\n        \r\n        updateValeurs<\/span>.<\/span>putNull<\/span>(<\/span>UserDictionary<\/span>.<\/span>Words<\/span>.<\/span>LOCALE<\/span>);<\/span>\r\n        \r\n        int<\/span> nombreEnregistrements<\/span> =<\/span> getContentResolver<\/span>().<\/span>update<\/span>(<\/span>\r\n                UserDictionary<\/span>.<\/span>Words<\/span>.<\/span>CONTENT_URI<\/span>,<\/span> updateValeurs<\/span>,<\/span>\r\n                selectionClause<\/span>,<\/span> selectionArgs<\/span>);<\/span>\r\n<\/pre>\n<\/div>\n
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        String<\/span> selectionClause<\/span> =<\/span> UserDictionary<\/span>.<\/span>Words<\/span>.<\/span>APP_ID<\/span> +<\/span> \" LIKE ?\"<\/span>;<\/span>\r\n        String<\/span>[]<\/span> selectionArgs<\/span> =<\/span> {<\/span>\"prog\"<\/span>};<\/span>\r\n        \r\n        int<\/span> nombreEnregistrements<\/span> =<\/span> getContentResolver<\/span>().<\/span>delete<\/span>(<\/span>\r\n            UserDictionary<\/span>.<\/span>Words<\/span>.<\/span>CONTENT_URI<\/span>,<\/span> selectionClause<\/span>,<\/span> selectionArgs<\/span>);<\/span>\r\n<\/pre>\n<\/div>\n
L’utilisation de ces fonctionnalit\u00e9s ne font pas partit du cours. Si vous voulez en savoir plus, je vous recommande d’aller lire la documentation officielle: https:\/\/developer.android.com\/guide\/topics\/providers\/content-providers<\/a><\/p>\n
Le MediaStore<\/h2>\n
Android utilise la m\u00e9canique de \u00ab\u00a0content provider\u00a0\u00bb afin de partager certaines informations syst\u00e8me. C’est le cas de la liste des informations des fichiers m\u00e9dias contenus dans le syst\u00e8me. Les informations qui nous permettront d’utiliser le \u00ab\u00a0content provider\u00a0\u00bb afin d’acc\u00e9der aux informations de fichiers m\u00e9dia se trouvent dans le MediaStore.<\/p>\n
Le MediaStore permet d’acc\u00e9der aux fichiers contenus dans les r\u00e9pertoires de m\u00e9dia de l’appareil Android. Voici les types de fichiers qui peuvent \u00eatre acc\u00e9d\u00e9s par le MediaStore:<\/p>\n