Update README.md

README.md

@@ -1,2 +1,67 @@
-# -week-selection-date-range-picker-flutter
-How to select a week in Flutter data range picker (SfDateRangePicker)?
+# How to select a week in the Flutter data range picker (SfDateRangePicker)
+
+In the flutter date range picker, you can select the entire week when selecting a single day using the `onSelectionChanged` callback and `enableSwipeSelection` property.
+
+## Step 1:
+In initState(), initialize the controller for date range picker.
+
+```xml
+DateRangePickerController _controller;
+@override
+void initState() {
+  // TODO: implement initState
+  _controller = DateRangePickerController();
+  super.initState();
+}
+```
+## Step 2:
+Place the date range picker inside the body of the Scaffold widget, set the `selectionMode` as range selection and trigger the `onSelectionChanged` callback of the flutter date picker.
+`
+```xml
+return Scaffold(
+  body: Column(
+    children: <Widget>[
+      Card(
+        margin: const EdgeInsets.fromLTRB(50, 100, 50, 100),
+        child: SfDateRangePicker(
+          controller: _controller,
+          view: DateRangePickerView.month,
+          selectionMode: DateRangePickerSelectionMode.range,
+          onSelectionChanged: selectionChanged,
+          monthViewSettings: DateRangePickerMonthViewSettings(enableSwipeSelection: false),
+        ),
+      )
+    ],
+  ), 
+);
+```
+
+## Step 3:
+Find the `startDate` and `endDate` from the `onSelectionChanged` event args. Calculate the first day of the week for `startDate`, `endDate`, and add the remaining dates to the start and end dates for the week selection. And assign those dates to the `selectedRange` property of controller. Please find the code for the same.
+
+```xml
+void selectionChanged(DateRangePickerSelectionChangedArgs args) {
+  int firstDayOfWeek = DateTime.sunday % 7;
+  int endDayOfWeek = (firstDayOfWeek - 1) % 7;
+  endDayOfWeek = endDayOfWeek < 0? 7 + endDayOfWeek : endDayOfWeek;
+  PickerDateRange ranges = args.value;
+  DateTime date1 = ranges.startDate;
+  DateTime date2 = ranges.endDate?? ranges.startDate;
+  if(date1.isAfter(date2))
+    {
+      var date=date1;
+      date1=date2;
+      date2=date;
+    }
+  int day1 = date1.weekday % 7;
+  int day2 = date2.weekday % 7;
+
+  DateTime dat1 = date1.add(Duration(days: (firstDayOfWeek - day1)));
+  DateTime dat2 = date2.add(Duration(days: (endDayOfWeek - day2)));
+
+  if( !isSameDate(dat1, ranges.startDate)|| !isSameDate(dat2,ranges.endDate))
+  {
+    _controller.selectedRange = PickerDateRange(dat1, dat2);
+  }
+}
+```