Features/GTK3/Porting: Difference between revisions

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If you are having trouble finding how a particular GTK class/method/constant has been named in PyGI, run [http://dev.laptop.org/~dsd/20110806/pygi-enumerate.py pygi-enumerate.py] and grep the output. (this app lists all identified methods and constants).

=== Constructor considerations ===

With PyGI it is possible to use Python-like constructors, or "new" functions e.g. the following are (probably) equivalent:

label = Gtk.Label()

label = Gtk.Label.new()

However, the first form is preferred: it is more Python-like. Internally, the difference is that Gtk.Label.new() translates to a call to gtk_label_new(), whereas Gtk.Label() (the preferred form) will directly construct an instance of GtkLabel at the GObject level.

If the constructor takes parameters, they '''must''' be named. The parameters correspond to GObject properties marked as "Construct" in the API documentation. For example, the following code will not work:

expander = Gtk.Expander("my expander")

The (confusing) error is:

TypeError: GObject.__init__() takes exactly 0 arguments (1 given)

The solution is to go to the [http://developer.gnome.org/gtk3/3.2/GtkExpander.html#GtkExpander.properties GtkExpander API documentation] and find the appropriate "Construct" property that we wish to set. In this case it is <b>label</b>, so the code should be:

expander = Gtk.Expander(label="my expander")

==Make a release==

@@ Line 90: / Line 90: @@
 If you are having trouble finding how a particular GTK class/method/constant has been named in PyGI, run [http://dev.laptop.org/~dsd/20110806/pygi-enumerate.py pygi-enumerate.py] and grep the output. (this app lists all identified methods and constants).
+=== Constructor considerations ===
+With PyGI it is possible to use Python-like constructors, or "new" functions e.g. the following are (probably) equivalent:
+ label = Gtk.Label()
+ label = Gtk.Label.new()
+However, the first form is preferred: it is more Python-like. Internally, the difference is that Gtk.Label.new() translates to a call to gtk_label_new(), whereas Gtk.Label() (the preferred form) will directly construct an instance of GtkLabel at the GObject level.
+If the constructor takes parameters, they '''must''' be named. The parameters correspond to GObject properties marked as "Construct" in the API documentation. For example, the following code will not work:
+ expander = Gtk.Expander("my expander")
+The (confusing) error is:
+ TypeError: GObject.__init__() takes exactly 0 arguments (1 given)
+The solution is to go to the [http://developer.gnome.org/gtk3/3.2/GtkExpander.html#GtkExpander.properties GtkExpander API documentation] and find the appropriate "Construct" property that we wish to set. In this case it is <b>label</b>, so the code should be:
+ expander = Gtk.Expander(label="my expander")
 ==Make a release==