Question

我正在尝试创建一个Android mp3播放器应用程序
我想扫描整个文件系统的mp3文件（第一次只有一次）
以下类负责扫描mp3文件

public class Mp3Scanner implements Runnable{
 private static final String TAG = "Mp3Scanner";
 final String MEDIA_PATH = new String("/");
 private String[] mp3Extensions = new String[]{".mp3",".MP3"};
 private ArrayList<HashMap<String,String>> songsList = new ArrayList<HashMap<String,String>>();
 private ArrayList<String> excludePath = new ArrayList<String>();
 private MediaMetadataRetriever mediaMetadataRetriever;
 public Mp3Scanner(){
    mediaMetadataRetriever = new MediaMetadataRetriever();
    excludePath.add("/sys");
    excludePath.add("/proc");
 }
 public ArrayList<HashMap<String, String>> getSongsList() {
    return songsList;
 }
 private void scanDir(File directory){
    if(directory != null){
        File[] listFiles = directory.listFiles();
        if(listFiles!=null && listFiles.length>0){
            for(File file : listFiles){
                if(file.isDirectory()){
                    Log.i(TAG, "Scanning Dir:" + file.getPath());
                    scanDir(file);
                }else{
                    addSongToList(file);
                }
            }
        }
    }
 }
 private void addSongToList(File song){
    if(song!=null && (song.getName().endsWith(mp3Extensions[0]) || song.getName().endsWith(mp3Extensions[1]))){
        HashMap<String,String> songInfo = new HashMap<String, String>();
        Log.i(TAG, "Adding Song:" + song.getPath());
        mediaMetadataRetriever.setDataSource(song.getPath());
        Log.i(TAG, "Album:" + mediaMetadataRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_ALBUM));
        Log.i(TAG, "AlbumArtish:" + mediaMetadataRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_ALBUMARTIST));
        Log.i(TAG,"Artist:"+mediaMetadataRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_ARTIST));
        Log.i(TAG,"Author:"+mediaMetadataRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_AUTHOR));
        Log.i(TAG,"Duration:"+mediaMetadataRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION));
        Log.i(TAG,"MimeType:"+mediaMetadataRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_MIMETYPE));
        Log.i(TAG,"Title:"+mediaMetadataRetriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_TITLE));
        songInfo.put("path", song.getPath());
        songInfo.put("name",song.getName());
        songsList.add(songInfo);
    }
 }
 @Override
 public void run() {
    long start = System.currentTimeMillis();
    Log.i(TAG, "Scan started at:"+start);
    scanForSongs();
    long stop = System.currentTimeMillis();
    Log.i(TAG, "Scan Completed at:"+stop);
    long timeTaken = stop - start;
    Log.i(TAG, "Total Time Taken To Scan:"+timeTaken);
 }
 public void scanForSongs() {
    Log.i(TAG, "Preparing List..");
    File home = new File(MEDIA_PATH);
    Log.i(TAG, home.getPath());
    File[] listFiles = home.listFiles();
    if(listFiles!=null)
        Log.i(TAG, "length:" + listFiles.length);
    if(listFiles!=null && listFiles.length>0){
        for(File file : listFiles){
            if(file.isDirectory() && !excludePath.contains(file.getAbsolutePath())){
                Log.i(TAG, "Scanning Dir:" + file.getPath());
                scanDir(file);
            }else{
                addSongToList(file);
            }
        }
    }
 }
}

上面的算法我从堆栈溢出问题的不同答案中找到了可以告诉我上述算法是否足够有效吗？因为现在大多数智能手机都包含32GB左右使用服务

执行上述代码服务或AsyncTask的更好方法是什么？

public class SongScanService extends Service {
 private static final String TAG = "Mp3Scanner";
 @Nullable
 @Override
 public IBinder onBind(Intent intent) {
    return null;
 }

 @Override
 public int onStartCommand(Intent intent, int flags, int startId) {
    Log.i(TAG,"OnStartCommand");
    Mp3Scanner mp3Scanner = new Mp3Scanner();
    Thread mp3Thread = new Thread(mp3Scanner);
       mp3Thread.start();
       // mp3Thread.join();
    String[] paths = FileUtility.getStorageDirectories();
    for(String path:paths){
        Log.i("Path From Utility:",path);
    }
    this.stopSelf();
    return Service.START_NOT_STICKY;
 }

 @Override
 public void onCreate() {
    super.onCreate();
    Log.i(TAG,"onCreate");
 }

 @Override
 public void onDestroy() {
    super.onDestroy();
    Log.i(TAG, "onDestroy");
 }
}

以下代码段用于从Activity

启动服务

Intent i = new Intent(this ,SongScanService.class);
startService(i);

使用AsyncTask

 public class SongScanTask extends AsyncTask<Void , Void, Void> {
 private static final String TAG = "SongScanTask";
 @Override
 protected Void doInBackground(Void... params) {
    Log.i(TAG, "AsyncTask Starting..");
    Mp3Scanner mp3Scanner = new Mp3Scanner();
    Thread mp3Thread = new Thread(mp3Scanner);
    mp3Thread.start();
    try {
        mp3Thread.join();
        ArrayList songsList = mp3Scanner.getSongsList();
        Log.i(TAG,"No.Of Songs Found:"+songsList.size());

    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    Log.i(TAG, "AsyncTask Completed..");
    return null;
}
}

以下代码段用于从活动

启动AsyncTask

new SongScanTask().execute();

我发现使用服务的扫描文件系统可能会停止ui，如果需要很长时间

什么是在android中扫描filesytem for mp3文件的更好方法？

0 个答案: