The getter 'last' was called on null

[gripzyyy]

Hi!
In a widget in an onPressed i use

DatePicker.showDatePicker(context,
dateFormat: 'HH/mm/ss');

When I press the button I get this error:
The following NoSuchMethodError was thrown building DatePickerWidget(dirty, state: _DatePickerWidgetState#7c286):
The getter 'last' was called on null.
Receiver: null
Tried calling: last
The relevant error-causing widget was
MaterialApp
When the exception was thrown, this was the stack
#0 Object.noSuchMethod (dart:core-patch/object_patch.dart:53:5)
#1 _DatePickerWidgetState._renderDatePickerColumnComponent
#2 _DatePickerWidgetState._renderDatePickerWidget.
#4 _DatePickerWidgetState._renderDatePickerWidget

[dylanwuzh]

没有指定pickerMode，默认是 DateTimePickerMode.date，dateFormat 的值不合法，H、m、s 之间的分隔符不包括 "/"，v1.0.23版本新增了pickerMode的校验，并且添加了分隔符 "/"
No pickerMode is specified, the default is DateTimePickerMode.date, the value of dateFormat is invalid, and the separator between H, m, and s does not include "/", pickerMode verification is added in v1.0.23, and a separator is added /.