问使用FileFilter的ListActivity

EN

public class SDCardExplorer extends ListActivity {

private String mediapath = new String(Environment.getExternalStorageDirectory().getAbsolutePath());

private List<String> item = null;
private List<String> path = null;

private TextView mypath;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.medialist);

    mypath = (TextView) findViewById(R.id.mypath);

    LoadDirectory(mediapath);
}

// class to limit the choices shown when browsing to SD card to media files
public class AudioFilter implements FileFilter {

    // only want to see the following audio file types
    private String[] extension = {".aac", ".mp3", ".wav", ".ogg", ".midi", ".3gp", ".mp4", ".m4a", ".amr", ".flac"};

    @Override
    public boolean accept(File pathname) {

        // if we are looking at a directory/file that's not hidden we want to see it so return TRUE
        if ((pathname.isDirectory() || pathname.isFile()) && !pathname.isHidden()){
            return true;
        }

        // loops through and determines the extension of all files in the directory
        // returns TRUE to only show the audio files defined in the String[] extension array
        for (String ext : extension) {
            if (pathname.getName().toLowerCase().endsWith(ext)) {
                return true;
            }
        }

        return false;
    }      
}

private void LoadDirectory(String dirPath) {      

    mypath.setText("Location: " + dirPath);

    item = new ArrayList<String>();
    path = new ArrayList<String>();

    File f = new File(dirPath);
    File[] files = f.listFiles(new AudioFilter());

    // If we aren't in the SD card root directory, add "Up" to go back to previous folder
    if(!dirPath.equals(mediapath)) {

        item.add("Up");
        path.add(f.getParent());
    }

    // Loops through the files and lists them
    for (int i = 0; i < files.length; i++) {
        File file = files[i];
        path.add(file.getPath());

        // Add "/" to indicate you are looking at a folder
        if(file.isDirectory()) {
          item.add(file.getName() + "/");
        }
        else {
          item.add(file.getName());
        }  
    }

    // Displays the directory list on the screen
    setListAdapter(new ArrayAdapter<String>(this, R.layout.mediaitems, item));
}