title: How to disable list of specific date on flutter
body: <p>I have a code to call showDatePicker, my question is how to disable list of specific date, one, two or more json dates?
  I try selectableDayPredicate with Saturday and Sunday disabled, but how to do disable with json list of date from api ?</p>
  
  <pre><code>                onTap: () {
                              showDatePicker(
                                context: context,
                                initialDate:
                                    DateTime.now().add(Duration(days: 2)),
                                firstDate:
                                    DateTime.now().add(Duration(days: 1)),
                                lastDate:
                                    DateTime.now().add(Duration(days: 730)),
                                selectableDayPredicate: (DateTime val) =&gt;
                                    val.weekday == 5 || val.weekday == 6
                                        ? false
                                        : true,
                              );
                            }
  </code></pre>