I'm a beginner in android and I want to create a simple MP3 player. But i got the following Exception.
NullPointerException - Attempt to get length of null array.
Using adb shell i verified in that path mp3 files are exist. This is my code
Activity Class
public class Display extends ListActivity {
Button stop;
private static final String PATH = new String("/sdcard/");
private List<String> songs = new ArrayList<String>();
private MediaPlayer mp = new MediaPlayer();
private ListView mainListView ;
String name;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listview);
stop = (Button) findViewById(R.id.stopbtn);
mainListView = getListView();
updatePlayList();
}
private void setButtonOnClickListeners(){
stop.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
mp.stop();
}
});}
@Override
protected void onListItemClick(ListView list, View view, int position, long id){
try{
mp.reset();
mp.setDataSource(PATH + songs.get(position));
mp.prepare();
mp.start();
}catch(IOException e){
Log.v("test", e.getMessage());
}}
private void updatePlayList() {
File home = new File(PATH);
for (File f : home.listFiles()) { // This line causes the exception
if (f.isFile())
name = f.getName();
if(name.contains(".MP3") || name.contains(".mp3")) {
ArrayAdapter<String> songList = new ArrayAdapter<String>(this, R.layout.simplerow, songs);
mainListView.setAdapter(songList);
}
}
}
}
I have added the read permission in manifest file also. And i tried with
Environment.getExternalStorageDirectory()
also. Can anyone help me?
