更新QStyle中的EnterEvent

Question

当鼠标进入\out小部件(enterEvent\leaveEvent )时，我想更新LineEdit的LineEdit，我试图在drawPrimitive函数中添加一个bool变量，但是我得到了错误TypeError: drawPrimitive(self，QStyle.PrimitiveElement，QStyleOption，QPainter，小部件: QWidget = None)：'a‘不是一个有效的关键字参数。

from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PushButton_2 import Push_Button_
import sys

class LineEditStyle(QProxyStyle):
    def drawPrimitive(self, element, option, painter, widget,a=None):
        if a :
            self.pen = QPen(QColor('green'))
        else :
            self.pen = QPen(QColor('red'))
        self.pen.setWidth(4)
        if element == QStyle.PE_FrameLineEdit:
            painter.setRenderHint(QPainter.Antialiasing)
            painter.setPen(self.pen)
            painter.drawRoundedRect(QRect(0,0,400,40), 10, 10)
        else:
            super().drawPrimitive(element, option, painter, widget)

        
class LineEdit(QLineEdit):
    def __init__(self,*args,**kwargs):
        QLineEdit.__init__(self,*args,**kwargs)
        self.a = 0
    
    def enterEvent(self, a0):
        self.a = 1

    def leaveEvent(self, a0):
        self.a = 0
        
    def paintEvent(self,event):
        option = QStyleOption()
        option.initFrom(self)
        self.style().drawPrimitive(QStyle.PE_FrameLineEdit,option,a=self.a)


if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = QMainWindow()
    window.setGeometry(500,500,400,400)
    window.setStyleSheet('background-color:#373737')
    line = LineEdit(parent=window)
    line.setGeometry(20,200,400,40)
    style = LineEditStyle()
    line.setStyle(style)
    window.show()
    sys.exit(app.exec())

Answer 1

不能将QStyleSheet与QStyle一起使用，因为它会造成混乱，并且必须将默认参数Widget设置为None

from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PushButton_2 import Push_Button_
import sys

class LineEditStyle(QProxyStyle):
    def drawPrimitive(self, element, option, painter, widget=None,a=None):
        if a :
            self.pen = QPen(QColor('green'))
        else :
            self.pen = QPen(QColor('red'))
        self.pen.setWidth(4)
        if element == QStyle.PE_FrameLineEdit:
            painter.setRenderHint(QPainter.Antialiasing)
            painter.setPen(self.pen)
            painter.drawRoundedRect(QRect(0,0,400,40), 10, 10)
        else:
            super().drawPrimitive(element, option, painter, widget)
    
    def subElementRect(self, element, option, widget):
        if element == QStyle.SE_LineEditContents :
            return QRect(0,0,50,30)
        else :
            return super().subElementRect(element, option, widget)
    
    def drawItemText(self, painter, rect, flags, pal, enabled, text, textRole):
        rect_ = QRect(20,20,50,50)
        text = text.upper()
        painter.drawText(text,rect_,Qt.AlignCenter)
        
class LineEdit(QLineEdit):
    def __init__(self,*args,**kwargs):
        QLineEdit.__init__(self,*args,**kwargs)
        self.a = 0
    
    def enterEvent(self, a0):
        self.a = 1

    def leaveEvent(self, a0):
        self.a = 0
        
    def paintEvent(self,event):
        option = QStyleOption()
        option.initFrom(self)
        painter = QPainter(self)
        self.style().drawPrimitive(QStyle.PE_FrameLineEdit,option,painter,a=self.a)


if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = QMainWindow()
    window.setGeometry(500,500,400,400)
    #window.setStyleSheet('background-color:#373737')
    line = LineEdit(parent=window)
    line.setGeometry(20,200,400,40)
    style = LineEditStyle()
    line.setStyle(style)
    window.show()
    sys.exit(app.exec())

Answer 2

您可能会发现QStyleSheets对于类似的事情很有用。

我在styleSheet中通过在styleSheet属性中输入以下内容(在代码中要执行mywidget.setStyleSheet('<parameters>') )来模拟这一点：

QLineEdit {
    border: 3px solid red;
}
QLineEdit:focus {
    border: 3px solid green;
}

编辑：上面的styleSheet字符串适用于焦点，但最初的问题是关于enterEvent/leaveEvent的，后者在鼠标悬停时触发。正如@musicamente正确地指出的，要处理鼠标悬停，可以使用:hover 伪态而不是:focus

QLineEdit {
    border: 3px solid red;
}
QLineEdit:hover {
    border: 3px solid green;
}

我用2 QMainWindow做了一个QLineEdits: 1有styleSheet集，另一个是默认的。当焦点移动到常规QLineEdit时，修改后的QLineEdit会变成红色。

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通过编辑父的styleSheet，您可以使QLineEdits的所有styleSheet行为相同。在您的情况下，您可以使用window.setStyleSheet('....。下面是Qt设计中的另一个模型：

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