Displaying Database value in Dialog Interface using android

When user clicks the button, I am fetching the database table content and displaying it in the Dialog Interface which is having check boxes for displaying names.The problem is when i click the button it "Stopped working" error.

Here is the code:

protected String[] Friends;

protected void showSelectFriendsDialog() {
    SQLiteDatabase db = playerDB.getReadableDatabase();

    String[] Friend = {"player_name"};

    Cursor cursor = db.query(DBHelper.DATABASE_TABLE_NAME_USERINFO, Friend, null, null,  null, null, null);

    if(cursor != null) {
        startManagingCursor(cursor);
        while (cursor.moveToNext()) {         
            String name = cursor.getString(0);

            for(int i = 0; i < cursor.getCount(); i++) {
                Friends[i] = name;
            }
        }
    }

    boolean[] checkedFriends = new boolean[Friends.length];
    int count = Friends.length;

    for(int i = 0; i < count; i++)
        checkedFriends[i] = selectedFriends.contains(Friends[i]);

    DialogInterface.OnMultiChoiceClickListener coloursDialogListener = new DialogInterface.OnMultiChoiceClickListener() {
        public void onClick(DialogInterface dialog, int which, boolean isChecked) {
            if(isChecked)
                selectedFriends.add(Friends[which]);
            else
                selectedFriends.remove(Friends[which]);
        }
    };

    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle("Select Friends");
    builder.setMultiChoiceItems(Friends, checkedFriends, coloursDialogListener);

    AlertDialog dialog = builder.create();
    dialog.show();
}

Here is the logcat:

01-07 12:17:50.770: E/AndroidRuntime(848): FATAL EXCEPTION: main
01-07 12:17:50.770: E/AndroidRuntime(848): java.lang.NullPointerException
01-07 12:17:50.770: E/AndroidRuntime(848):  at apk.game.mindwords.Play.showSelectFriendsDialog(Play.java:235)
01-07 12:17:50.770: E/AndroidRuntime(848):  at apk.game.mindwords.Play.onClick(Play.java:191)
01-07 12:17:50.770: E/AndroidRuntime(848):  at android.view.View.performClick(View.java:4084)
01-07 12:17:50.770: E/AndroidRuntime(848):  at android.view.View$PerformClick.run(View.java:16966)
01-07 12:17:50.770: E/AndroidRuntime(848):  at android.os.Handler.handleCallback(Handler.java:615)
01-07 12:17:50.770: E/AndroidRuntime(848):  at android.os.Handler.dispatchMessage(Handler.java:92)
01-07 12:17:50.770: E/AndroidRuntime(848):  at android.os.Looper.loop(Looper.java:137)
01-07 12:17:50.770: E/AndroidRuntime(848):  at android.app.ActivityThread.main(ActivityThread.java:4745)
01-07 12:17:50.770: E/AndroidRuntime(848):  at java.lang.reflect.Method.invokeNative(Native Method)
01-07 12:17:50.770: E/AndroidRuntime(848):  at java.lang.reflect.Method.invoke(Method.java:511)
01-07 12:17:50.770: E/AndroidRuntime(848):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
01-07 12:17:50.770: E/AndroidRuntime(848):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
01-07 12:17:50.770: E/AndroidRuntime(848):  at dalvik.system.NativeStart.main(Native Method)