How to add a timer/clock in android studio

Question

I am making an application, in which the user has to answer a series of questions under a certain amount of time, let's say 10seconds. I have gotten most of the code but the timer part. I want the current activity to end and either show a Toast or switch to some different activity.

I tried TimerTask and Timer classes but they don't seem to work, no idea why.

     Timer t = new Timer();
     TimerTask timerTask = new TimerTask() {
         @Override
         public void run() {
             Toast.makeText(LevelOne.this, "Times up!!!", Toast.LENGTH_SHORT).show();
             startNextLevel();
         }
     };
     t.schedule(timerTask,5000L );

     private void startNextLevel() {
         Intent nextLevel = new Intent(this, LevelTwo.class);
         startActivity(nextLevel);
     }