I have an array String populated by data taken from the database.
Now for each row of the array I want to add a day to the calendar, the line \"0\" day today, the line \"1\" tom
You can just get the time in milliseconds and then add a day worth of milliseconds to it.
Calendar prova = Calendar.getInstance();
int size = id_op.length;
for(int i = 0; i< size; i++){
Long time = prova.getTimeInMillis();
time = time + 86400000;
prova.setTimeInMillis(time);
}