media player problem between raw folder and sdcard on android
<p>hi 
i am doing app for playing song with seek bar. if play from raw folder it works but if i play song from sdcard it shows null pointer exception.</p>

<pre><code>private MediaPlayer mediaPlayer;

mediaPlayer = MediaPlayer.create(this, R.raw.t1); // it works

//  switch to sdcard

  mediaPlayer.setDataSource("/sdcard/t1.mp3"); // null pointer exception.
</code></pre>

<p>i do not know what is the problem. please help me.</p>
