python3+PyQt5 自定义窗口部件--使用窗口部件样式表的方法

本文借用HTML的css语法，将样式表应用到窗口部件。这里只是个简单的例子，实际上样式表的语法很丰富。

以下类似于css：

StyleSheet = """
QComboBox { color: darkblue; }
QLineEdit { color: darkgreen; }
QLineEdit[mandatory="true"] { #mandatory="true"时，QLineEdit的样式会变化
background-color: rgb(255, 255, 127);
color: darkblue;
}

如果在选择器的前面加上一个句点，比如.QLineEdit，则选择器就会只应用于指定的类，而不会应用于这个类的子类。如果要求选择器仅用于某一特定窗口部件，则可以对该窗口部件调用setObjectName(),然后用该名字作为选择器的一部分。比如，如果有一个按钮，其对象名字是“findButton”，则应用于这个按钮的选择器就应该是QpushButton#findButton。有些窗口部件会有一些子控件。例如QComboBox会有一个箭头子控件，用户通过点击这个箭头来看到下拉列表。子控件可以指定为选择器的一部分–例如，QComboBox::drop-down。伪状态可以用一个冒号指定–例如，QCheckBox::checked.

#!/usr/bin/env python3

import sys
from PyQt5.QtWidgets import (QApplication, QComboBox, QDialog,
 QDialogButtonBox, QGridLayout, QLabel, QLineEdit, QVBoxLayout)

class ContactDlg(QDialog):

StyleSheet = """
QComboBox { color: darkblue; }
QLineEdit { color: darkgreen; }
QLineEdit[mandatory="true"] {
background-color: rgb(255, 255, 127);
color: darkblue;
}
"""

def __init__(self, parent=None):
 super(ContactDlg, self).__init__(parent)

forenameLabel = QLabel("&Forename:")
 self.forenameEdit = QLineEdit()
 forenameLabel.setBuddy(self.forenameEdit)
 surnameLabel = QLabel("&Surname:")
 self.surnameEdit = QLineEdit()
 surnameLabel.setBuddy(self.surnameEdit)
 categoryLabel = QLabel("&Category:")
 self.categoryComboBox = QComboBox()
 categoryLabel.setBuddy(self.categoryComboBox)
 self.categoryComboBox.addItems(["Business", "Domestic",
         "Personal"])
 companyLabel = QLabel("C&ompany:")
 self.companyEdit = QLineEdit()
 companyLabel.setBuddy(self.companyEdit)
 addressLabel = QLabel("A&ddress:")
 self.addressEdit = QLineEdit()
 addressLabel.setBuddy(self.addressEdit)
 phoneLabel = QLabel("&Phone:")
 self.phoneEdit = QLineEdit()
 phoneLabel.setBuddy(self.phoneEdit)
 mobileLabel = QLabel("&Mobile:")
 self.mobileEdit = QLineEdit()
 mobileLabel.setBuddy(self.mobileEdit)
 faxLabel = QLabel("Fa&x:")
 self.faxEdit = QLineEdit()
 faxLabel.setBuddy(self.faxEdit)
 emailLabel = QLabel("&Email:")
 self.emailEdit = QLineEdit()
 emailLabel.setBuddy(self.emailEdit)
 self.buttonBox = QDialogButtonBox(QDialogButtonBox.Ok|
          QDialogButtonBox.Cancel)
 addButton = self.buttonBox.button(QDialogButtonBox.Ok)
 addButton.setText("&Add")
 addButton.setEnabled(False)

grid = QGridLayout()
 grid.addWidget(forenameLabel, 0, 0)
 grid.addWidget(self.forenameEdit, 0, 1)
 grid.addWidget(surnameLabel, 0, 2)
 grid.addWidget(self.surnameEdit, 0, 3)
 grid.addWidget(categoryLabel, 1, 0)
 grid.addWidget(self.categoryComboBox, 1, 1)
 grid.addWidget(companyLabel, 1, 2)
 grid.addWidget(self.companyEdit, 1, 3)
 grid.addWidget(addressLabel, 2, 0)
 grid.addWidget(self.addressEdit, 2, 1, 1, 3)
 grid.addWidget(phoneLabel, 3, 0)
 grid.addWidget(self.phoneEdit, 3, 1)
 grid.addWidget(mobileLabel, 3, 2)
 grid.addWidget(self.mobileEdit, 3, 3)
 grid.addWidget(faxLabel, 4, 0)
 grid.addWidget(self.faxEdit, 4, 1)
 grid.addWidget(emailLabel, 4, 2)
 grid.addWidget(self.emailEdit, 4, 3)
 layout = QVBoxLayout()
 layout.addLayout(grid)
 layout.addWidget(self.buttonBox)
 self.setLayout(layout)

self.lineedits = (self.forenameEdit, self.surnameEdit,
   self.companyEdit, self.phoneEdit, self.emailEdit)
 for lineEdit in self.lineedits:
  lineEdit.setProperty("mandatory", True)
  lineEdit.textEdited.connect(self.updateUi)
 self.categoryComboBox.activated.connect(self.updateUi)

self.buttonBox.accepted.connect(self.accept)
 self.buttonBox.rejected.connect(self.reject)
 self.setStyleSheet(ContactDlg.StyleSheet)
 self.setWindowTitle("Add Contact")

def updateUi(self):
 mandatory = bool(self.companyEdit.property("mandatory"))
 if self.categoryComboBox.currentText() == "Business":
  if not mandatory:
   self.companyEdit.setProperty("mandatory", True)
 elif mandatory:
  self.companyEdit.setProperty("mandatory", False)
 if (mandatory !=
  bool(self.companyEdit.property("mandatory"))):
  self.setStyleSheet(ContactDlg.StyleSheet)

enable = True
 for lineEdit in self.lineedits:
  if (bool(lineEdit.property("mandatory")) and
   not lineEdit.text()):
   enable = False
   break
 self.buttonBox.button(QDialogButtonBox.Ok).setEnabled(enable)

if __name__ == "__main__":
app = QApplication(sys.argv)
form = ContactDlg()
form.show()
app.exec_()

运行结果：

来源：https://blog.csdn.net/xiaoyangyang20/article/details/55224242