How to display progress dialog?

private ProgressDialog dialog;
public void onCreate(Bundle savedInstanceState) {    
    ……
    
    dialog = ProgressDialog.show(this, "",  
            "Loading Calendar and Tasks. Please wait...", true);
    
    ……
    CalendarThread calendarThread = new CalendarThread();
    calendarThread.start(); 
    
}

private class CalendarThread extends Thread { 
         
    @Override 
    public void run() {         
        //Long running process
        ……

        handler.sendEmptyMessage(0); 
    } 

    private Handler handler = new Handler() { 

        @Override 
        public void handleMessage(Message msg) { 
            //Process after the long running process
            ……
            dialog.dismiss(); 
        } 
    }; 
}