Migration to null safety + little code shorten (#51)

* updated intl and dart sdk versions

* intl version fix

* migrated date widget to null safety

* migrated date picker widget

* update pubspec yaml autogenerated by migration tool

Author: juampiq6

lib/date_picker_widget.dart

@@ -1,3 +1,5 @@
+
+
 import 'package:date_picker_timeline/date_widget.dart';
 import 'package:date_picker_timeline/extra/color.dart';
 import 'package:date_picker_timeline/extra/style.dart';
@@ -17,7 +19,7 @@ class DatePicker extends StatefulWidget {
   final double height;
 
   /// DatePicker Controller
-  final DatePickerController controller;
+  final DatePickerController? controller;
 
   /// Text color for the selected Date
   final Color selectedTextColor;
@@ -38,18 +40,18 @@ class DatePicker extends StatefulWidget {
   final TextStyle dateTextStyle;
 
   /// Current Selected Date
-  final DateTime initialSelectedDate;
+  final DateTime?/*?*/ initialSelectedDate;
 
   /// Contains the list of inactive dates.
   /// All the dates defined in this List will be deactivated
-  final List<DateTime> inactiveDates;
+  final List<DateTime>? inactiveDates;
 
   /// Contains the list of active dates.
   /// Only the dates in this list will be activated.
-  final List<DateTime> activeDates;
+  final List<DateTime>? activeDates;
 
   /// Callback function for when a different date is selected
-  final DateChangeListener onDateChange;
+  final DateChangeListener? onDateChange;
 
   /// Max limit up to which the dates are shown.
   /// Days are counted from the startDate
@@ -60,7 +62,7 @@ class DatePicker extends StatefulWidget {
 
   DatePicker(
     this.startDate, {
-    Key key,
+    Key? key,
     this.width = 60,
     this.height = 80,
     this.controller,
@@ -86,17 +88,17 @@ class DatePicker extends StatefulWidget {
 }
 
 class _DatePickerState extends State<DatePicker> {
-  DateTime _currentDate;
+  DateTime? _currentDate;
 
   ScrollController _controller = ScrollController();
 
-  TextStyle selectedDateStyle;
-  TextStyle selectedMonthStyle;
-  TextStyle selectedDayStyle;
+  late final TextStyle selectedDateStyle;
+  late final TextStyle selectedMonthStyle;
+  late final TextStyle selectedDayStyle;
 
-  TextStyle deactivatedDateStyle;
-  TextStyle deactivatedMonthStyle;
-  TextStyle deactivatedDayStyle;
+  late final TextStyle deactivatedDateStyle;
+  late final TextStyle deactivatedMonthStyle;
+  late final TextStyle deactivatedDayStyle;
 
   @override
   void initState() {
@@ -106,42 +108,26 @@ class _DatePickerState extends State<DatePicker> {
     _currentDate = widget.initialSelectedDate;
 
     if (widget.controller != null) {
-      widget.controller.setDatePickerState(this);
+      widget.controller!.setDatePickerState(this);
     }
 
     this.selectedDateStyle =
-        createTextStyle(widget.dateTextStyle, widget.selectedTextColor);
+      widget.dateTextStyle.copyWith(color: widget.selectedTextColor);
     this.selectedMonthStyle =
-        createTextStyle(widget.monthTextStyle, widget.selectedTextColor);
+      widget.monthTextStyle.copyWith(color: widget.selectedTextColor);
     this.selectedDayStyle =
-        createTextStyle(widget.dayTextStyle, widget.selectedTextColor);
+        widget.dayTextStyle.copyWith(color: widget.selectedTextColor);
 
     this.deactivatedDateStyle =
-        createTextStyle(widget.dateTextStyle, widget.deactivatedColor);
+        widget.dateTextStyle.copyWith(color: widget.deactivatedColor);
     this.deactivatedMonthStyle =
-        createTextStyle(widget.monthTextStyle, widget.deactivatedColor);
+        widget.monthTextStyle.copyWith(color: widget.deactivatedColor);
     this.deactivatedDayStyle =
-        createTextStyle(widget.dayTextStyle, widget.deactivatedColor);
+        widget.dayTextStyle.copyWith(color: widget.deactivatedColor);
 
     super.initState();
   }
 
-  /// This will return a text style for the Selected date Text Values
-  /// the only change will be the color provided
-  TextStyle createTextStyle(TextStyle style, Color color) {
-    if (color != null) {
-      return TextStyle(
-        color: color,
-        fontSize: style.fontSize,
-        fontWeight: style.fontWeight,
-        fontFamily: style.fontFamily,
-        letterSpacing: style.letterSpacing,
-      );
-    } else {
-      return style;
-    }
-  }
-
   @override
   Widget build(BuildContext context) {
     return Container(
@@ -162,7 +148,7 @@ class _DatePickerState extends State<DatePicker> {
           // check if this date needs to be deactivated for only DeactivatedDates
           if (widget.inactiveDates != null) {
 //            print("Inside Inactive dates.");
-            for (DateTime inactiveDate in widget.inactiveDates) {
+            for (DateTime inactiveDate in widget.inactiveDates!) {
               if (_compareDate(date, inactiveDate)) {
                 isDeactivated = true;
                 break;
@@ -173,7 +159,7 @@ class _DatePickerState extends State<DatePicker> {
           // check if this date needs to be deactivated for only ActivatedDates
           if (widget.activeDates != null) {
             isDeactivated = true;
-            for (DateTime activateDate in widget.activeDates) {
+            for (DateTime activateDate in widget.activeDates!) {
               // Compare the date if it is in the
               if (_compareDate(date, activateDate)) {
                 isDeactivated = false;
@@ -184,20 +170,26 @@ class _DatePickerState extends State<DatePicker> {
 
           // Check if this date is the one that is currently selected
           bool isSelected =
-              _currentDate != null ? _compareDate(date, _currentDate) : false;
+              _currentDate != null ? _compareDate(date, _currentDate!) : false;
 
           // Return the Date Widget
           return DateWidget(
             date: date,
             monthTextStyle: isDeactivated
                 ? deactivatedMonthStyle
-                : isSelected ? selectedMonthStyle : widget.monthTextStyle,
+                : isSelected
+                    ? selectedMonthStyle
+                    : widget.monthTextStyle,
             dateTextStyle: isDeactivated
                 ? deactivatedDateStyle
-                : isSelected ? selectedDateStyle : widget.dateTextStyle,
+                : isSelected
+                    ? selectedDateStyle
+                    : widget.dateTextStyle,
             dayTextStyle: isDeactivated
                 ? deactivatedDayStyle
-                : isSelected ? selectedDayStyle : widget.dayTextStyle,
+                : isSelected
+                    ? selectedDayStyle
+                    : widget.dayTextStyle,
             width: widget.width,
             locale: widget.locale,
             selectionColor:
@@ -207,8 +199,8 @@ class _DatePickerState extends State<DatePicker> {
               if (isDeactivated) return;
 
               // A date is selected
-              if (widget.onDateChange != null ) {
-                widget.onDateChange(selectedDate);
+              if (widget.onDateChange != null) {
+                widget.onDateChange!(selectedDate);
               }
               setState(() {
                 _currentDate = selectedDate;
@@ -230,7 +222,7 @@ class _DatePickerState extends State<DatePicker> {
 }
 
 class DatePickerController {
-  _DatePickerState _datePickerState;
+  _DatePickerState? _datePickerState;
 
   void setDatePickerState(_DatePickerState state) {
     _datePickerState = state;
@@ -241,8 +233,8 @@ class DatePickerController {
         'DatePickerController is not attached to any DatePicker View.');
 
     // jump to the current Date
-    _datePickerState._controller
-        .jumpTo(_calculateDateOffset(_datePickerState._currentDate));
+    _datePickerState!._controller
+        .jumpTo(_calculateDateOffset(_datePickerState!._currentDate!));
   }
 
   /// This function will animate the Timeline to the currently selected Date
@@ -252,8 +244,8 @@ class DatePickerController {
         'DatePickerController is not attached to any DatePicker View.');
 
     // animate to the current date
-    _datePickerState._controller.animateTo(
-        _calculateDateOffset(_datePickerState._currentDate),
+    _datePickerState!._controller.animateTo(
+        _calculateDateOffset(_datePickerState!._currentDate!),
         duration: duration,
         curve: curve);
   }
@@ -265,19 +257,19 @@ class DatePickerController {
     assert(_datePickerState != null,
         'DatePickerController is not attached to any DatePicker View.');
 
-    _datePickerState._controller.animateTo(_calculateDateOffset(date),
+    _datePickerState!._controller.animateTo(_calculateDateOffset(date),
         duration: duration, curve: curve);
   }
 
   /// Calculate the number of pixels that needs to be scrolled to go to the
   /// date provided in the argument
   double _calculateDateOffset(DateTime date) {
     final startDate = new DateTime(
-        _datePickerState.widget.startDate.year,
-        _datePickerState.widget.startDate.month,
-        _datePickerState.widget.startDate.day);
+        _datePickerState!.widget.startDate.year,
+        _datePickerState!.widget.startDate.month,
+        _datePickerState!.widget.startDate.day);
 
     int offset = date.difference(startDate).inDays;
-    return (offset * _datePickerState.widget.width) + (offset * 6);
+    return (offset * _datePickerState!.widget.width) + (offset * 6);
   }
 }

lib/date_widget.dart

@@ -10,19 +10,19 @@ import 'package:flutter/material.dart';
 import 'package:intl/intl.dart';
 
 class DateWidget extends StatelessWidget {
-  final double width;
+  final double? width;
   final DateTime date;
-  final TextStyle monthTextStyle, dayTextStyle, dateTextStyle;
+  final TextStyle? monthTextStyle, dayTextStyle, dateTextStyle;
   final Color selectionColor;
-  final DateSelectionCallback onDateSelected;
-  final String locale;
+  final DateSelectionCallback? onDateSelected;
+  final String? locale;
 
   DateWidget({
-    @required this.date,
-    @required this.monthTextStyle,
-    @required this.dayTextStyle,
-    @required this.dateTextStyle,
-    @required this.selectionColor,
+    required this.date,
+    required this.monthTextStyle,
+    required this.dayTextStyle,
+    required this.dateTextStyle,
+    required this.selectionColor,
     this.width,
     this.onDateSelected,
     this.locale,
@@ -58,7 +58,7 @@ class DateWidget extends StatelessWidget {
         // Check if onDateSelected is not null
         if (onDateSelected != null) {
           // Call the onDateSelected Function
-          onDateSelected(this.date);
+          onDateSelected!(this.date);
         }
       },
     );

pubspec.yaml

@@ -4,12 +4,12 @@ version: 1.2.1
 homepage: https://github.com/iamvivekkaushik/DatePickerTimelineFlutter
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   flutter:
     sdk: flutter
-  intl: ^0.16.1
+  intl: ^0.17.0
 
 dev_dependencies:
   flutter_test: