Calculating the number of days between two selected dates in a DateChooser control

Here’s a marginally more interesting sample. I was playing around with the DateChooser (calendar) control and the selectableRange property and figured I’d make a simple application to calculate the differences between two selected dates. The example creates a selectable range of dates from the current date to current date plus 1 year. Users can select any single or range of dates between the start date and end date, and Flex calculates the number of days the user selected using some basic math.

<?xml version="1.0" encoding="utf-8"?>
<mx:Application name="DateChooser_selectableRange_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">
 
    <mx:Script>
        <![CDATA[
            import mx.controls.dataGridClasses.DataGridColumn;
 
            /* Number of milliseconds in a day. (1000 milliseconds per second * 60 seconds per minute * 60 minutes per hour * 24 hours per day) */
            private const MS_PER_DAY:uint = 1000 * 60 * 60 * 24;
 
            [Bindable]
            private var startDate:Date = new Date();
 
            [Bindable]
            private var endDate:Date = new Date(startDate.fullYear + 1, startDate.month, startDate.date);
 
            /* Default label function for the DataGrid. Basically just calls the DateFormatter on the current column's contents. */
            private function cellDateFormatter(item:Object, column:DataGridColumn):String {
                var columnDataField:String = column.dataField;
                return dateFormatter.format(item[columnDataField]);
            }
 
            /* Custom label function for the last column. Calculates the number of days between the start date and end date. */
            private function calculateDays(item:Object, column:DataGridColumn):String {
                var tempDate:Date = new Date(item.rangeEnd - item.rangeStart);
                return Math.round((tempDate.time / MS_PER_DAY) + 1).toString();
            }
        ]]>
    </mx:Script>
 
    <mx:DateFormatter id="dateFormatter" formatString="MMM D, YYYY" />
 
    <mx:HBox>
        <mx:DateChooser id="dateChooser" selectableRange="{{rangeStart:startDate, rangeEnd:endDate}}" allowMultipleSelection="true" />
 
        <mx:DataGrid id="selDates" dataProvider="{dateChooser.selectedRanges}" labelFunction="cellDateFormatter" verticalScrollPolicy="on" height="{dateChooser.height}">
            <mx:columns>
                <mx:DataGridColumn dataField="rangeStart" headerText="Range Start:" />
                <mx:DataGridColumn dataField="rangeEnd" headerText="Range End:" />
                <mx:DataGridColumn labelFunction="calculateDays" headerText="Number Days:" />
            </mx:columns>
        </mx:DataGrid>
    </mx:HBox>
 
</mx:Application>

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26 thoughts on “Calculating the number of days between two selected dates in a DateChooser control

  1. Sandeep,

    Try clicking on Aug 6th, pressing the Shift key, and then pressing on Aug 22nd.
    It should highlight each of the days between the two dates, set the range, and list the number of days as 17.

    If you press the Ctrl key, I believe it selects each day individually instead of as a range/series.

  2. Rhoby,

    I’m sure there is a better, more efficient way, but maybe this helps:

    <?xml version="1.0" encoding="utf-8"?>
    <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
            layout="vertical"
            verticalAlign="middle"
            backgroundColor="white">
    
        <mx:Script>
            <![CDATA[
                import mx.events.CalendarLayoutChangeEvent;
                import mx.utils.ObjectUtil;
    
                private var msInDay:uint = 1000 * 60 * 60 * 24;
    
                private function dateChooser_change(evt:CalendarLayoutChangeEvent):void {
                    // textArea.text = ObjectUtil.toString(dateChooser.selectedRanges);
                    textArea.text = "";
                    if (dateChooser.selectedRanges.length > 0) {
                        var ranges:Object = dateChooser.selectedRanges[0];
                        var numDays:uint = (ranges.rangeEnd.time - ranges.rangeStart.time) / msInDay;
                        var idx:uint;
                        var retDate:Date;
                        for (idx = 0; idx <= numDays; idx++) {
                            retDate = new Date(ranges.rangeStart.time);
                            retDate.date += idx;
                            textArea.text += retDate.toDateString() + "\n";
                        }
                    }
                }
            ]]>
        </mx:Script>
    
        <mx:DateChooser id="dateChooser"
                allowMultipleSelection="true"
                change="dateChooser_change(event);" />
    
        <mx:TextArea id="textArea"
                editable="false"
                selectable="false"
                width="320"
                height="240" />
    
    </mx:Application>
    

    Peter

  3. Hello Petered

    First, very big thank you for having responded …
    I never thought you were answering me still thank you very much
    This site told me everything about Flex and I hope with all my heart that will never end …
    This is the solution that I was looking for …
    You are the best, MANY THANKS

  4. Hello Petered,

    We are working with Flex Builder 3 and We need to select multiple days in a calendar
    without pressing the Ctrl or Shift keys. Is it possible?

    Thanks

  5. Your example seems to demonstrate the same bug(?) I’m experiencing. When the selectableRange is defined on a DateChooser and allowMultipleSelection=”true”, the selectedRanges do not include the rangeStart. In fact, in your example (at least on my machine), you can’t even select a range that includes the rangeStart date. Anyone else experiencing this?

  6. ABC,

    Try clicking on Aug 6th, pressing the Shift key, and then pressing on Aug 22nd.
    It should highlight each of the days between the two dates, set the range, and list the number of days as 17.

    If you press the Ctrl key, I believe it selects each day individually instead of as a range/series.

    Peter

  7. flex_learner,

    You could do something like the following, which will set the selected date to July 4, 1980 and then set the DateChooser control’s displayed month and year to that same date:

    <?xml version="1.0" encoding="utf-8"?>
    <mx:Application name="DateChooser_selectedDate_test"
            xmlns:mx="http://www.adobe.com/2006/mxml"
            layout="vertical"
            verticalAlign="middle"
            backgroundColor="white">
    
        <mx:Date id="dat" fullYear="1980" month="6" date="4" />
    
        <mx:DateChooser id="dateChooser"
                selectedDate="{dat}"
                displayedYear="{dat.fullYear}"
                displayedMonth="{dat.month}" />
    
    </mx:Application>
    

    The previous code will give a couple of binding warnings saying:
    (a) Data binding will not be able to detect assignments to “fullYear”.
    (b) Data binding will not be able to detect assignments to “month”.

    The example still works, but if you don’t like those warnings, you could always set the properties using ActionScript instead, as seen in the following example:

    <?xml version="1.0" encoding="utf-8"?>
    <mx:Application name="DateChooser_selectedDate_test"
            xmlns:mx="http://www.adobe.com/2006/mxml"
            layout="vertical"
            verticalAlign="middle"
            backgroundColor="white">
    
        <mx:Script>
            <![CDATA[
                import mx.events.CalendarLayoutChangeEvent;
    
                private function dateChooser_change(evt:CalendarLayoutChangeEvent):void {
                    var selDat:Date = dateChooser.selectedDate;
                    dateChooser.displayedYear = selDat.fullYear;
                    dateChooser.displayedMonth = selDat.month;
                }
            ]]>
        </mx:Script>
    
        <mx:DateChooser id="dateChooser"
                change="dateChooser_change(event);">
            <mx:selectedDate>
                <mx:Date fullYear="1980" month="6" date="4" />
            </mx:selectedDate>
        </mx:DateChooser>
    
        <mx:Button id="btn"
                label="Set new selectedDate"
                click="dateChooser.selectedDate = new Date(1976, 8, 9);" />
    
    </mx:Application>
    

    Peter

  8. Peter,

    why the need for Math.round?

    return Math.round((tempDate.time / MS_PER_DAY) + 1).toString();

    you’d think that item.rangeEnd & item.rangeStart wouldn’t have any time associated with it. but i have seen weird things where the difference in milliseconds between 2 dates is often not perfectly divisible by 1000 * 60 * 60 * 24. Which seems very odd…

  9. public static const millisecondsPerDay:int = 1000 * 60 * 60 * 24;

    I guess this will do

    private function getDaysDifference(minDate:Date, maxDate:Date):uint
    {
    // for testing 
    // var newDate:Date = new Date(2007,9,23); 
    // var oldDate:Date = new Date (2007, 8, 23);
    return Math.ceil(( minDate.getTime() - maxDate.getTime()) / millisecondsPerDay);
    }
  10. Hi,

    i have a problem face from last day.

    The problem is that i want to run a countdown Timer. The timer is start from two dates
    1. current date (as New Date()).
    2. the immediate Monday (as new Date(“Mon Jan 17 2011″))

    The problem is with 2nd date.

    How i dynamically find the next Monday date ?.

    Thanks and welcome for Help.

      1. Thanks Peter.

        And if i want to get always UTC time on my PC or another PC in which my app is run, What i do that for this ?

  11. Not every day is 1000 * 60 * 60 * 24 milliseconds long.

    In EST we have 2 days a year that are 23 and 25 hours long to account for daylight savings time.

  12. hey could you tell me how to find the number of days between two dates using both datefield and datechooser also BindingUtils.bindProperty should be used.

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