Thursday, March 30, 2017

PyGTK - Calendar Class

The Calendar widget in PyGTK toolkit displays a simple calendar with one month view at a time. The navigation controls to change month and year are displayed by default. The display options can be suitably configured.

The value of month property is between 0 to 11, and that of date property is between 1 to 31.
There is a simple constructor to create a gtk.Calendar object −
cal = gtk.Calendar()
The default display style shows the current month and year as well as names of days.
The gtk.Calendar class has the following methods −
  • Calendar.select_month(mm,yy) — This changes the calendar display to the specified mm and yy.
  • Calendar.select_day(dd) — This selects the specified dd on the calendar when it has a value between 1 and 31. If dd is 0 then the current day selection is removed.
  • Calendar.display_options() — This sets the calendar display options to the value specified by flags. The possible display options are a combination of:
gtk.CALENDAR_SHOW_HEADING Specifies that the month and year should be displayed.
gtk.CALENDAR_SHOW_DAY_NAMES Specifies that three letter day descriptions should be present.
gtk.CALENDAR_NO_MONTH_CHANGE Prevents the user from switching months with the calendar.
gtk.CALENDAR_SHOW_WEEK_NUMBERS Displays each week numbers of the current year, down the left side of the calendar.
gtk.CALENDAR_WEEK_START_MONDAY Starts the calendar week on Monday, instead of the default Sunday.
  • Calendar.get_date() — This retrieves the calendar's current year, month and selected day numbers as a tuple (year, month, day).
The gtk.Calendar widget emits the following signals −
day-selected This is emitted when a day is selected either by the user or programmatically.
month-changed This is emitted when the calendar month is changed programmatically or by the user.
next-month This is emitted when the user clicks the "next-month" navigation control in the calendar header.
next-year This is emitted when the user clicks the "next-year" navigation control in the calendar header.
prev-month This is emitted when the user clicks the "prev-month" navigation control in the calendar header.
prev-year This is emitted when the user clicks the "prev-year" navigation control in the calendar header.
In the following example, a gtk.Calendar control and four buttons are placed in the toplevel window.
When the 'heading' button is clicked, the Calendar's display options are set to SHOW_HEADING −
def heading(self, widget):
   self.cal.set_display_options(gtk.CALENDAR_SHOW_HEADING)
When the user clicks the 'day name' button, the callback sets display options to SHOW_DAY_NAMES −
def dayname(self, widget):
self.cal.set_display_options(gtk.CALENDAR_SHOW_DAY_NAMES)
Both the display options are enabled when 'both' button is pressed. To begin with, all flags of display options are removed by setting it to 0.
self.cal.set_display_options(0)
The 'set' button pops up a message box displaying the currently marked date.
tp = self.cal.get_date()
str1 = str(tp[0])
str2 = str(tp[1]+1)
str3 = str(tp[2])
label = gtk.Label("Date selected:"+str3+"-"+str2+"-"+str1)
dialog.vbox.add(label)
label.show()

Example

Observe the following code −
import gtk
class PyApp(gtk.Window):
   
   def __init__(self):
      super(PyApp, self).__init__()
      self.set_title("Calendar Demo")
      self.set_size_request(300, 200)
      self.set_position(gtk.WIN_POS_CENTER)
  
      vbox = gtk.VBox(False, 5)
      self.cal = gtk.Calendar()
      halign1 = gtk.Alignment(0.5, 0.5, 0, 0)
      halign1.add(self.cal)
  
      self.cal.set_display_options(0)
      valign = gtk.Alignment(0, 1, 0, 0)
      vbox.pack_start(halign1)
  
      self.btn1 = gtk.Button("set")
      self.btn2 = gtk.Button("heading")
      self.btn3 = gtk.Button("day name")
      self.btn4 = gtk.Button("Both")
  
      hbox = gtk.HBox(True, 3)
      hbox.add(self.btn1)
      hbox.add(self.btn2)
      hbox.add(self.btn3)
      hbox.add(self.btn4)
  
      halign = gtk.Alignment(0.5, 0.5, 0, 0)
      halign.add(hbox)
  
      vbox.pack_start(halign, False, True, 10)
      self.add(vbox)
  
      self.btn1.connect("clicked", self.selectdate)
      self.btn2.connect("clicked", self.heading)
      self.btn3.connect("clicked", self.dayname)
      self.btn4.connect("clicked", self.bothflags)
  
      self.connect("destroy", gtk.main_quit)
      self.show_all()
  
   def heading(self, widget):
      self.cal.set_display_options(gtk.CALENDAR_SHOW_HEADING)
  
   def dayname(self, widget):
      self.cal.set_display_options(gtk.CALENDAR_SHOW_DAY_NAMES)
  
   def bothflags(self, widget):
      self.cal.set_display_options(gtk.CALENDAR_SHOW_HEADING|gtk.CALENDAR_SHOW_DAY_NAMES)
   def selectdate(self, widget):
      tp = self.cal.get_date()
      dialog = gtk.Dialog("My dialog",
      self,
      gtk.DIALOG_MODAL | gtk.DIALOG_DESTROY_WITH_PARENT,
      (gtk.STOCK_OK, gtk.RESPONSE_ACCEPT))
  
      str1 = str(tp[0])
      str2 = str(tp[1]+1)
      str3 = str(tp[2])
  
      label = gtk.Label("Date selected:"+str3+"-"+str2+"-"+str1)
      dialog.vbox.add(label)
      label.show()
      res = dialog.run()
      dialog.destroy()
PyApp()
gtk.main()
The above code will generate the following output −
Calendar Demo

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