Using progressbar

You might have used ProgressDialog in your android app. This can be used to tell the user that some long processing is going on like file operation or accessing data from net.

A progressbar is similar to a progress dialog. It is used to show the progress of a lengthy operation. 

Progress bar can be horizontal or indeterminate - which is a wheel like thing which keeps rotating. We can specify which we need horizontal instead of indeterminate with style option

         <ProgressBar
            android:id="@+id/time"
            style="?android:attr/progressBarStyleHorizontal"
            android:layout_width="fill_parent"
          
            android:layout_height="wrap_content" />

in the xml file.


Using horizontal progressbar for countdown

Consider the case where you want to show how much time is left for your user to complete his quiz. Your progress bar should be horizontal and it should start from full and stop at 0 when time out. 

Updating the progress of progressbar is done with 

    pbTimeLeft.setProgress(value);

The maximum value of progressbar can be set as
    
     pbTimeLeft.setMax(maxValue);

To use a count down timing for this progress bar, you should also use countdown timer.
 
 mCountDownTimer = new CountDownTimer(totaltime, time_update_interval) {

            @Override
            public void onFinish() {
                doFinishStuffHere();

            }

            @Override
            public void onTick(long millisUntilFinished) {
                
                pbTimeLeft.setProgress((int) millisUntilFinished);
            }

        }.start();