/flutter/.pub-cache/hosted/pub.flutter-io.cn/flutter_cupertino_date_picker-1.0.26+2/lib/src/date_picker_theme.dart:23:7: Error: The type ‘DiagnosticableMixin’ can’t be mixed in.
class DateTimePickerTheme with DiagnosticableMixin {
Solution:
class DateTimePickerTheme with DiagnosticableMixin {
Solution:
After Flutter 1.22+ the DiagnosticableMixin class is gone, modify the source code of the date_picker_theme.dart class and replace it with Diagnosticable.
class DateTimePickerTheme with DiagnosticableMixin {