为什么 G_IS_OBJECT（对象）因 Gio.PropertyAction.new 而失败？

Question

在 python3/pygobjects/gtk+3 应用程序中，我试图通过 Gio.PropertyAction 通过切换按钮控制属性。不幸的是，我似乎无法创建动作。

我把它归结为这个最小的例子：

import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gio, Gtk, GObject

class Obj(GObject.GObject):
    prop = GObject.property(type = int)

    def __init__(self):
        action = Gio.PropertyAction.new('act', self, 'prop')

obj = Obj()

它产生了这个错误：

(test.py:9099): GLib-GIO-CRITICAL **: g_property_action_new: assertion 'G_IS_OBJECT (object)' failed
Traceback (most recent call last):
  File "./test.py", line 11, in <module>
    obj = Obj()
  File "./test.py", line 9, in __init__
    action = Gio.PropertyAction.new('act', self, 'prop')
TypeError: constructor returned NULL

根据 Python GTK+ 3 Tutorial this is the correct way to handle properties. Curiously though, the Python GI API Reference does not know of GObject.GObject, but has only GObject.Object and requires it as second argument for Gio.PropertyAction.new (compare Gio.PropertyAction.new).

我做错了什么？

Answer 1

错误在于，我没有调用父构造函数，即 GObject.GObject 中的构造函数。以下作品：

import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gio, Gtk, GObject

class Obj(GObject.GObject):
    prop = GObject.property(type = int)

    def __init__(self):
        super().__init__()
        action = Gio.PropertyAction.new('act', self, 'prop')

obj = Obj()

为什么 G_IS_OBJECT（对象）因 Gio.PropertyAction.new 而失败？

Why does G_IS_OBJECT (object) fail for Gio.PropertyAction.new?

python

pygobject

gtk3