我有以下内容
class MyView(QWidget):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
layout = QVBoxLayout()
layout.addWidget(QLabel('Hello World'))
self.setLayout(layout)
class NavigationMenu(QWidget):
pass
# Renders a bar of full width and 15 px height
将NavigationMenu
添加到MyView
的最简单方法是什么?
在将来,我还必须将NavigationMenu
添加到所有其他视图中,因此我正在寻找可从打字和可维护性角度进行扩展的内容。
我尝试了装饰器(只是在类顶部的@NavigationMenuDecorator
),但我要么不能绑定它们,要么它们在解析时初始化并且错误QWidget: Must construct a QApplication before a QWidget
。
我尝试将其添加到MyView中,但是有很多样板
class MyWidget(Widget.QWidget):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
layout = Widget.QVBoxLayout()
layout.addWidget(QLabel('Hello World'))
topLayout = Widget.QVBoxLayout()
topLayout.setContentsMargins(0, 0, 0, 0)
topLayout.addWidget(NavigationMenu())
topLayout.addLayout(layout)
self.setLayout(topLayout)
一种可能的解决方案是使用元类:
from PyQt5 import QtCore, QtWidgets
class NavigationMenu(QtWidgets.QWidget):
def __init__(self, parent=None):
super().__init__(parent)
lay = QtWidgets.QVBoxLayout(self)
lay.addWidget(QtWidgets.QLabel("NavigationMenu"))
class MetaNavigationMenu(type(QtWidgets.QWidget), type):
def __call__(cls, *args, **kw):
obj = super().__call__(*args, **kw)
lay = obj.layout()
if lay is not None:
lay.addWidget(NavigationMenu())
return obj
class View(QtWidgets.QWidget, metaclass=MetaNavigationMenu):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
layout = QtWidgets.QVBoxLayout()
layout.addWidget(QtWidgets.QLabel('Hello World'))
self.setLayout(layout)
if __name__=="__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
w = View()
w.show()
sys.exit(app.exec_())
更新:
使用以下方法,您可以注入视图以及视图所需的其他参数:
from PyQt5 import QtCore, QtWidgets
class NavigationMenu(QtWidgets.QWidget):
def __init__(self, value, text="", parent=None):
super().__init__(parent)
lay = QtWidgets.QVBoxLayout(self)
lay.addWidget(QtWidgets.QLabel(text))
print(value)
class MetaMenu(type(QtWidgets.QWidget), type):
def __new__(cls, class_name, parents, attrs, **kwargs):
cls._view = kwargs.pop('view', None)
cls._args = kwargs.pop('args', tuple())
cls._kwargs = kwargs.pop('kwargs', dict())
return type.__new__(cls, class_name, parents, attrs)
def __call__(cls, *args, **kw):
obj = super().__call__(*args, **kw)
layout = getattr(obj, 'layout', None)
if callable(layout) and View is not None:
layout().addWidget(cls._view(*cls._args, **cls._kwargs))
return obj
class View(QtWidgets.QWidget, metaclass=MetaMenu, view=NavigationMenu, args=(10, ), kwargs={"text": "NavigationMenu"}):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
layout = QtWidgets.QVBoxLayout()
layout.addWidget(QtWidgets.QLabel('Hello World'))
self.setLayout(layout)
if __name__=="__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
w = View()
w.show()
sys.exit(app.exec_())
这里的另一个解决方案是惊人的,我学到了很多关于元类的知识。但是,它很难阅读并增加了不必要的复杂性。我选择了基于组合的方法,我只是将样板提取到一个单独的函数中。
add_navigation()
函数将旧布局包装在窗口小部件中,使用NavigationMenu
和旧布局创建QVBoxLayout,最后交换布局。
def add_navigation(widget, title)
main = QWidget()
main.setLayout(widget.layout())
layout = QVBoxLayout()
layout.setContentsMargins(0, 0, 0, 0)
layout.setSpacing(0)
layout.addWidget(NavigationBar(title))
layout.addWidget(main)
widget.setLayout(layout)
然后,我们只有一个样板的样板,然后代码就变成了。
class MyView(QWidget):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
layout = QVBoxLayout()
layout.addWidget(QLabel('Hello World'))
self.setLayout(layout)
add_navigation(self, 'Navigation Title')
class NavigationMenu(QWidget):
pass
# Renders a bar of full width and 15 px height