you need to use the runOnUIThread()
function I have an example somwhere that I will post when I find it.
you need to give your timer an instance of MainActivity alternatively see this question I asked Android image timing issues with what sounds like a similar thing to what you were trying to do
public static void updateText(Activity act, resID)
{
loadingText = (TextView) activity.findViewById(R.id.loadingScreenTextView);
act.runOnUiThread(new Runnable()
{
public void run()
{
loadingText.setText(resID);
}
});
}