Activity is important ui unit of android application.   To start an activity from another, you have to use an intent by sending the new activity class as parameter.   e.g.            Intent i = new Intent(this, NewActivity.class);    Next you call startActivity method         startActivity(i);   You can pass extra data to the new actiivity by using putExtra method.        i.putExtra( "Title",mTitle);    In the new activity, you can extract this information using getExtra methods       Intent i = getIntent();     String t = i.getStringExtra("Title");