Timestamp to string date

String S = "1350574775";

You are sending your timestamp in seconds, instead of milliseconds.

Do this, instead:

String S = "1350574775000";

Or, in your getDate method, multiply by 1000L:

new Date(Long.parseLong(timeStampStr) * 1000L)

try this if you're sticking with "1350574775" format which is in seconds:

private void onCreate(Bundle bundle){
    ....
    String S = "1350574775";

    //convert unix epoch timestamp (seconds) to milliseconds
    long timestamp = Long.parseLong(s) * 1000L; 
    czas.setText(getDate(timestamp ));  
}



private String getDate(long timeStamp){

    try{
        SimpleDateFormat sdf = new SimpleDateFormat("MM/dd/yyyy");
        Date netDate = (new Date(timeStamp));
        return sdf.format(netDate);
    }
    catch(Exception ex){
        return "xx";
    }
}