我的代码生成一个包含两个 QWidget 的窗口,一个红色 (wg1
) 和一个蓝色 (wg2
).如果它们变成继承自 QWidget 的 Fields(注释掉),它们的颜色就会消失.
My code generates a Window containing two QWidgets, a red (wg1
) and a blue (wg2
) one. If they become Fields (commented out) which inherits from QWidget, their color disappears.
我的问题是:为什么 Field
(继承自 QWidget
)需要有一行
My question is: Why is it necessary for a Field
(which inherits from QWidget
), to have the line
self.setAttribute(Qt.WA_StyledBackground, True)
在它的 __init__
方法中,而 QWidget 不需要这一行?
in its __init__
-method while a QWidget doesn't need this line?
import sys
from PyQt5 import QtWidgets
from PyQt5.QtWidgets import QWidget, QApplication, QGridLayout
from PyQt5.QtCore import Qt
class Field(QWidget):
def __init__(self, name):
super().__init__()
self.name = name
# self.setAttribute(Qt.WA_StyledBackground, True)# !!!
def mousePressEvent(self, event):
print(f" click makes {self.name} green")
self.setStyleSheet("background: #00ff00;")
if __name__ == "__main__":
app = QApplication(sys.argv)
root = QWidget()
grid = QGridLayout()
root.setLayout(grid)
root.resize(300,100)
wg1 = QWidget()
wg2 = QWidget()
# wg1 = Field('wg1')
# wg2 = Field('wg2')
wg1.setStyleSheet("background: #aa1111;")
grid.addWidget(wg1, 0, 0)
wg2.setStyleSheet("background: #1111aa;")
grid.addWidget(wg2, 0, 2)
root.show()
sys.exit(app.exec_())
解释在样式表参考中与 QWidget 相关的部分:
如果您从 QWidget 继承,您需要为您的自定义 QWidget 提供一个paintEvent,如下所示:
If you subclass from QWidget, you need to provide a paintEvent for your custom QWidget as below:
默认情况下,QWidget 会默认执行此操作,但 QWidget 子类不会,因此您要么设置标志,要么实现paintEvent.
By default, QWidget does that by default, but QWidget subclasses do not, so you either set the flag or you implement the paintEvent.
无论如何,请考虑使用 样式表选择器 并避免通用/通用语法,因为它们通常会导致复杂的子小部件出现意外行为.
In any case, consider using stylesheet selectors and avoid generic/universal syntax as they often result in unexpected behavior for complex child widgets.
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