Get current week number

[schiessle]

Hi,

I'm looking for a way to get the current week number. I had a look at the date object but couldn't find a method for it. Any idea how to get/calculate the week number?

Thanks!

[SGaist]

Hi,

The QDate class has a method for that.

[schiessle]

Hi,

thanks for the answer. How can I use QDate from within a QML script? Soemthing like "new QDate()" seems not to work.

And the date object returns a "undefined" if I try to access weekNumber:

var d = new Date();
d.weekNumber;

Thanks!

[ODБOï]

@schiessle hi
that is c++ method

 QDate date(2019,03,07); 
 int weekNbr = date.weekNumber();

you can do this and make weekNbr reachable from QML using setContextProperty() method:

int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
    QGuiApplication app(argc, argv);
    QQmlApplicationEngine engine;

     QDate date(2019,03,07);  
     int weekNbr = date.weekNumber();

     engine.rootContext()->setContextProperty("weekNbr",weekNbr);

//use it in QML

Component.onCompleted: {console.log("weekNbr : " + weekNbr)}

or full js : (source https://weeknumber.net/how-to/javascript)

Component.onCompleted: {
    var date = new Date();
      date.setHours(0, 0, 0, 0);
      // Thursday in current week decides the year.
      date.setDate(date.getDate() + 3 - (date.getDay() + 6) % 7);
      // January 4 is always in week 1.
      var week1 = new Date(date.getFullYear(), 0, 4);
      // Adjust to Thursday in week 1 and count number of weeks from date to week1.

    console.log(1 + Math.round(((date.getTime() - week1.getTime()) / 86400000
                                - 3 + (week1.getDay() + 6) % 7) / 7))
}

[schiessle]

@LeLev Thanks for the detailed example and the link to the JavaScript example.

I chosed the JavaScript way and it works nicely!

Background: I use a Qt program which allows to write "plugins" as QML scripts. I want to write such a plugin. Therefore I need a way to get the week number without patching the main program to expose the week number. That's why I choosed the JS way.

[hskoglund]

@LeLev Careful with those js libraries, if you want valid week numbers on the year 2029 or later, maybe choose another library. It just did a quick test (someone please verify)


The first difference I found is on New Year's Eve 2029 (see first picture, screen shot of my Ubuntu 18.04)

2nd picture is a dump of weeknumber using that javascript code, ranging from December 28 to January 4 the following year (i.e. 8 days in a row).

3rd picture is a similar dump using QDate.weekNumber();
(Also New Year's Eve 2035 differs)