PyQt6中QLabel无法设置为完全不透明的问题求助（macOS）

我开发了一个PyQt6应用，包含一个窗口，未修改默认样式。希望实现鼠标悬停表格项时，显示提示框样式的QLabel，但无论如何设置样式表，都无法让QLabel背景完全不透明。

使用以下样式表代码：

stylesheet = "QLabel{opacity:1; background: red; border: 1px solid white};;"

label.setStyleSheet(window_stylesheet)

得到的效果仍为半透明，我使用的是macOS系统，请问如何让QLabel渲染为完全不透明？

附最小可复现代码：

# hello.py

"""Simple Hello, World example with PyQt6."""

import sys
# 1. Import QApplication and all the required widgets
from PyQt6.QtWidgets import QApplication, QLabel, QWidget, QTableWidget, QTableWidgetItem, QComboBox, QPushButton, QStyle, QStyleFactory
# hello.py
# ...

data = {
    "col1": ['1', '2', '3', '4'],
    "col2": ['1', '2', '3', '4'],
    "col3": ['1', '2', '3', '4'],
    "col4": ['1', '2', '3', '4']
}

 
class myTableView(QTableWidget):
    def __init__(self, data, *args):
        QTableWidget.__init__(self, *args)
        self.data = data
        self.setData(data)
        self.resizeColumnsToContents()
        self.resizeRowsToContents()
        self.setAlternatingRowColors(True)
        stylesheet  = "QTableView:item{border-top: 1px solid rgba(255,255,255,0.2)}"
        stylesheet_hovered  = "QTableView:item:hover{background-color: rgba(255,255,255,0.3); border-top: 1px solid rgba(255,255,255,0.2)}"
        self.setStyleSheet(stylesheet)
        self.setStyleSheet(stylesheet_hovered)
        self.setMouseTracking(True)
        self.current_hover = [0, 0]
        self.cellEntered.connect(self.cellHover)

 
    def setData(self, data): 
        self.data = data
        horHeaders = []
        for n, key in enumerate(list(self.data.keys())):
            horHeaders.append(key)
            for m, item in enumerate(self.data[key]):
                newitem = QTableWidgetItem(item)
                self.setItem(m, n, newitem)
        self.setHorizontalHeaderLabels(horHeaders)
        self.resizeColumnsToContents()
        self.resizeRowsToContents()

    def cellHover(self, row, column):
        item = self.item(row, column)
        old_item = self.item(self.current_hover[0], self.current_hover[1])

        infodict = {
            x: self.data[x][row] for x in list(self.data.keys())
        }
        if self.current_hover != [row,column]:
            if self.datatip.explaination_thread is not None:
                self.datatip.cancelExplaination()     # Cancel old datatip
        
            self.datatip.showExplaination(infodict)

        self.current_hover = [row, column]


class registerDataTip(QLabel):

    def __init__(self, *args):
        QTableWidget.__init__(self, *args)
        self.setText('DATATIP')
        self.explaination_thread = None
        self.close()

    def showExplaination(self, infodict):
        self.setText(f'<b>{infodict["col1"]}</b><br>This is a test string<br>I should be opaque but I am not')
        self.adjustSize()
        # self.explaination_thread = setTimeout(1, self.show)
        self.show()

    def cancelExplaination(self):
        self.close()


        # self.show()

# 2. Create an instance of QApplication
app = QApplication([])

# 3. Create your application's GUI
window = QWidget()
window.setWindowTitle("PyQt App")
# window.setStyle(QStyleFactory.create('Fusion')) # won't work on windows style.

window.setGeometry(100, 100, 280, 80)

window_stylesheet = "QLabel{opacity:1; background: red; border: 1px solid white;};;"

app.setStyleSheet(window_stylesheet)
#app.setStyleSheet(label_stylesheet)

table_meaning = myTableView(data,  len(data[list(data.keys())[0]]), len(list(data.keys())), window)
label_meaning = registerDataTip(window)
label_meaning.move(800,500)
table_meaning.datatip = label_meaning
table_meaning.setGeometry(60, 100, 600, 800)

random_button = QPushButton(window)
random_button.move(800,500)


# 4. Show your application's GUI
window.showMaximized()

# 5. Run your application's event loop
sys.exit(app.exec())

问题根源有两个：

1. 错误的继承初始化：registerDataTip类继承自QLabel，但__init__方法错误调用了QTableWidget.__init__，导致控件渲染逻辑混乱，出现半透明异常。
2. macOS原生样式干扰：即使修复继承问题，macOS的Qt原生样式可能默认给QLabel添加半透明处理，需要强制关闭相关属性。

修复步骤：

1. 修正继承初始化逻辑 #

将registerDataTip的__init__方法改为调用QLabel.__init__，同时强制关闭半透明背景属性：

from PyQt6.QtCore import Qt  # 需要导入Qt模块

class registerDataTip(QLabel):
    def __init__(self, *args):
        QLabel.__init__(self, *args)  # 修正为QLabel的初始化方法
        self.setText('DATATIP')
        self.explaination_thread = None
        self.setAttribute(Qt.WA_TranslucentBackground, False)  # 强制禁用半透明背景
        self.close()

2. 调整样式表 #

明确指定背景色的不透明度为100%，避免样式歧义：

window_stylesheet = "QLabel{background-color: rgba(255,0,0,1); border: 1px solid white; color: black;}"
app.setStyleSheet(window_stylesheet)

3. 修复表格样式覆盖问题 #

原代码中两次调用setStyleSheet会覆盖之前的样式，应合并为一次：

stylesheet = """
QTableView:item{border-top: 1px solid rgba(255,255,255,0.2)}
QTableView:item:hover{background-color: rgba(255,255,255,0.3); border-top: 1px solid rgba(255,255,255,0.2)}
"""
self.setStyleSheet(stylesheet)

完成以上修改后，QLabel的背景会完全不透明，符合预期效果。

内容的提问来源于stack exchange，提问作者Gianfranco Di Domenico