从Android设备获取.mp3格式的文件

我正在开发一个音乐播放器。 我想从Android设备获取所有.mp3格式的文件。 但是这段代码没有得到任何文件。 我的.mp3文件位于’sdcard / music’文件夹中。 如果我更改了MEDIA_PATH = new String("sdcard/music"); 像这样它只从该音乐文件夹中获取文件。 但我需要从外部/内部存储卡中的每个文件夹中获取所有.mp3文件。 请帮帮我。 这是我的代码。

 final String MEDIA_PATH = new String(Environment.getExternalStorageDirectory()); public void Generate_Database(){ File home = new File(MEDIA_PATH); if (home.listFiles(new FileExtensionFilter()).length > 0) { for (File file : home.listFiles(new FileExtensionFilter())) { String title = file.getName().substring(0, (file.getName().length() - 4)); String path = file.getPath(); mediaInfo.setDataSource(path); String albumName = "unknown",artist = "unknown",genere = "unknown",duration = "unknown",composer = "unknown"; if(mediaInfo.extractMetadata(MediaMetadataRetriever.METADATA_KEY_ALBUM) == null) albumName = "unknown"; else{ albumName = mediaInfo.extractMetadata(MediaMetadataRetriever.METADATA_KEY_ALBUM); } if(mediaInfo.extractMetadata(MediaMetadataRetriever.METADATA_KEY_ARTIST) == null) artist = "unknown"; else{ artist = mediaInfo.extractMetadata(MediaMetadataRetriever.METADATA_KEY_ARTIST); } if(mediaInfo.extractMetadata(MediaMetadataRetriever.METADATA_KEY_GENRE) == null) genere = "unknown"; else{ genere = mediaInfo.extractMetadata(MediaMetadataRetriever.METADATA_KEY_GENRE); } if(mediaInfo.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION) == null) duration = "unknown"; else{ duration = mediaInfo.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION); } if(mediaInfo.extractMetadata(MediaMetadataRetriever.METADATA_KEY_COMPOSER) == null) composer = "unknown"; else{ composer = mediaInfo.extractMetadata(MediaMetadataRetriever.METADATA_KEY_COMPOSER); } //Toast.makeText(getApplicationContext(), title+path+ albumName+artist+ genere+ duration+ composer, Toast.LENGTH_LONG).show(); ds.createEntry2(title, path, albumName, artist, genere, duration, composer); } } 

这用于提取.mp3文件

 class FileExtensionFilter implements FilenameFilter { public boolean accept(File dir, String name) { return (name.endsWith(".mp3") || name.endsWith(".MP3")); } } 

Answer 1

1. 查询媒体文件
2. 通过检查文件的扩展名来检查文件是否为mp3

以下方法将返回设备中的所有mp3音频文件：

 private List scanDeviceForMp3Files(){ String selection = MediaStore.Audio.Media.IS_MUSIC + " != 0"; String[] projection = { MediaStore.Audio.Media.TITLE, MediaStore.Audio.Media.ARTIST, MediaStore.Audio.Media.DATA, MediaStore.Audio.Media.DISPLAY_NAME, MediaStore.Audio.Media.DURATION }; final String sortOrder = MediaStore.Audio.AudioColumns.TITLE + " COLLATE LOCALIZED ASC"; List mp3Files = new ArrayList<>(); Cursor cursor = null; try { Uri uri = android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI; cursor = getContentResolver().query(uri, projection, selection, null, sortOrder); if( cursor != null){ cursor.moveToFirst(); while( !cursor.isAfterLast() ){ String title = cursor.getString(0); String artist = cursor.getString(1); String path = cursor.getString(2); String displayName = cursor.getString(3); String songDuration = cursor.getString(4); cursor.moveToNext(); if(path != null && path.endsWith(".mp3")) { mp3Files.add(path); } } } // print to see list of mp3 files for( String file : mp3Files) { Log.i("TAG", file); } } catch (Exception e) { Log.e("TAG", e.toString()); }finally{ if( cursor != null){ cursor.close(); } } return mp3Files; }