flutter - 错误: The argument type 'Null Function(DateTime, List<dynamic>)' can't be assigned to the parameter

Question

我与此面临着同样的问题

     Error: 
        The argument type 'Null Function(DateTime, List<dynamic>)' can't be assigned 
        to the parameter type 'void Function(DateTime, List<dynamic>, List<dynamic>)'.
        - 'DateTime' is from 'dart:core'. - 'List' is from 'dart:core'. 
        onDaySelected: (day, events) {

Answer 1

那是避免错误的一种方法

onDaySelected: (date, event, _) {
    print(date.toIso8601String());
},