Question

Is is possible to set the phone’s timezone programmatically in android? I got this code

 Calendar calendar = Calendar.getInstance();       
 SimpleDateFormat sdf = new SimpleDateFormat("dd-MMM-yyyy hh:mm:ss z");
 sdf.setTimeZone(TimeZone.getTimeZone("America/Los_Angeles"));
 System.out.println(sdf.format(calendar.getTime()));

but it does not change the phone’s timezone. It only displays the timezone of America/Los Angeles.

Answer 1

The code you are showing simply defines a Calendar instance with a specific format to be used in the app.
It is not possible to change the phone’s timezone programmatically.

You could redirect the user to the appropriate settings:

startActivity(new Intent(android.provider.Settings.ACTION_DATE_SETTINGS));