对话框未显示

Question

我想知道为什么run方法没有显示任何对话框，我甚至怀疑它是否会向arraylist添加任何文件。也许我将不得不使用一个处理程序来显示对话框，但是我如何在这里合并一个处理程序plz guide。

public class Homescreen extends Activity implements OnClickListener, Runnable {

ImageButton play, repeat, previous, next, playlist, shuffle, playlister1;
Intermediate inter;
ListView LVSongs;
Toast t1;
ArrayAdapter<String> songsAdapter;
Thread t;
Handler handler;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.homescreen);

initialize();
initializeListeners();
LVSongs.setOnItemClickListener(new OnItemClickListener() {

    @Override
    public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
            long arg3) {
        // TODO Auto-generated method stub

    }
});
}

private void initializeListeners() {
// TODO Auto-generated method stub
play.setOnClickListener(this);
repeat.setOnClickListener(this);
previous.setOnClickListener(this);
shuffle.setOnClickListener(this);
playlist.setOnClickListener(this);
next.setOnClickListener(this);
playlister1.setOnClickListener(this);
}

private void initialize() {
// TODO Auto-generated method stub
play = (ImageButton) findViewById(R.id.IBPlay);
repeat = (ImageButton) findViewById(R.id.IBRepeat);
previous = (ImageButton) findViewById(R.id.IBPrevious);
next = (ImageButton) findViewById(R.id.IBNext);
playlist = (ImageButton) findViewById(R.id.IBPlaylist);
shuffle = (ImageButton) findViewById(R.id.IBShuffle);
LVSongs = (ListView) findViewById(R.id.LVplaylist);
songsAdapter = new ArrayAdapter<String>(this,
        android.R.layout.simple_list_item_1, Serviceman.songs);
LVSongs.setAdapter(songsAdapter);
playlister1 = ((ImageButton) findViewById(R.id.IBPlaylist1));
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.homescreen, menu);
return true;
}

@Override
public void onClick(View clickedVariable) {
// TODO Auto-generated method stub
switch (clickedVariable.getId()) {
case R.id.IBPlay:

    break;
case R.id.IBNext:

    break;
case R.id.IBPrevious:

    break;
case R.id.IBPlaylist:

    break;
case R.id.IBRepeat:

    break;
case R.id.IBShuffle:

    break;
case R.id.IBPlaylist1:
    Intent playlist = new Intent(getApplicationContext(),
            playlist.class);
    startActivity(playlist);
}
}

@Override
public void run() {
// TODO Auto-generated method stub
// HashMap<String, String> song;
Uri allsongsuri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
String[] STAR = { "*" };
String selection = MediaStore.Audio.Media.IS_MUSIC + " != 0";
@SuppressWarnings("deprecation")
Cursor cursor = managedQuery(allsongsuri, STAR, selection, null, null);
ProgressDialog dialog = new ProgressDialog(Homescreen.this,
        android.R.style.Animation_Translucent);
dialog.setMax(100);
try {
    if (cursor != null) {
        if (cursor.moveToFirst()) {
            do {
                dialog.show();
                // song = new HashMap<String, String>();
                // SongName
                String song_name = cursor
                        .getString(cursor
                                .getColumnIndex(MediaStore.Audio.Media.DISPLAY_NAME));
                dialog.setMessage(song_name);
                // path
                String fullpath = cursor.getString(cursor
                        .getColumnIndex(MediaStore.Audio.Media.DATA));


                Serviceman.songs.add(song_name);
                songsAdapter.notifyDataSetChanged();

                dialog.incrementProgressBy(5);
            } while (cursor.moveToNext());
            dialog.dismiss();
        }
    }
} catch (NullPointerException exp) {
    Log.e("~~Null Pointer Exception~~", exp.toString());
    android.util.Log.e("->>", "~~stacktrace~~", exp);
} catch (Exception exp) {
    Log.e("~~Exception~~", exp.toString());
}
}