PyQt5 非模态对话框(apply 型)

import sys
from PyQt5.QtCore import Qt, pyqtSignal
from PyQt5.QtGui import QFont
from PyQt5.QtWidgets import *
#非模态对话框("Apply"型更新),字体选择组合框,自定义信号
class FontPropertiesDlg(QDialog):
 
    applySignal = pyqtSignal(str,int,bool)#自定义信号
 
    def __init__(self,parent=None):
        super().__init__(parent)
        #print(self.parent().windowTitle())
        FontStyleLabel = QLabel("字体:")
        self.FontstyleComboBox = QFontComboBox()#字体选择组合框
        self.FontEffectCheckBox =QCheckBox("使用特效")
        FontSizeLabel = QLabel("字体大小")
        self.FontSizeSpinBox = QSpinBox()
        self.FontSizeSpinBox.setRange(6, 36)
        self.FontSizeSpinBox.setValue(12)
        #这次没有采用QButtonBox
        okButton = QPushButton("应用")
        cancelButton = QPushButton("关闭")
        buttonLayout = QHBoxLayout()
 
        buttonLayout.addStretch()
        buttonLayout.addWidget(okButton)
        buttonLayout.addWidget(cancelButton)
        layout = QGridLayout()
 
        layout.addWidget(FontStyleLabel, 0, 0)
        layout.addWidget(self.FontstyleComboBox, 0, 1)
        layout.addWidget(FontSizeLabel, 1, 0)
        layout.addWidget(self.FontSizeSpinBox, 1, 1)
        layout.addWidget(self.FontEffectCheckBox,1,2)
        layout.addLayout(buttonLayout, 2, 2)
        self.setLayout(layout)
        okButton.clicked.connect(self.accept)
        cancelButton.clicked.connect(self.reject)
 
        self.setWindowTitle("字体")
    def accept(self):#重新实现accept方法
        #发射自定义信号
        self.applySignal.emit(self.FontstyleComboBox.currentText(),
                              self.FontSizeSpinBox.value(),
                              self.FontEffectCheckBox.isChecked())
        #也可以 调用 self.parent()得到父窗口的句柄，从而向父窗口传递值
        #和控制父窗口的行为，但是耦合度过高，不推荐
        #print(self.parent())
        #print(self.topLevelWidget())#Pyqt5中此方法没有了？
 
        #self.hide()#应用后隐藏，为了可以连续点应用按钮，一般不隐藏
 
class MainDialog(QDialog):
    def __init__(self,parent=None):
        super(MainDialog,self).__init__(parent)
        self.FontPropertiesDlg=None
        self.format=dict(fontstyle="宋体",fontsize=10,fonteffect=False)
        FontButton = QPushButton("设置字体(非模态)")
        self.label = QLabel("默认选择")
        layout = QGridLayout()
        layout.addWidget(FontButton,0,0)
        layout.addWidget(self.label)
        self.setLayout(layout)
        FontButton.clicked.connect(self.FontModalessDialog)
 
        self.setWindowTitle("非模态对话框")
        #self.setFixedSize(self.width(), 100)#固定窗口大小
 
        self.labelFont = QFont(self.format["fontstyle"],self.format["fontsize"])
        self.updateLabel()
        self.modalessDialog = None#初始值设为空，
 
    def updateLabel(self):
        self.label.setFont(self.labelFont)
        self.label.setText("选择的字体：%s    字体大小：%d    是否特效：%s" %(self.format["fontstyle"],self.format["fontsize"],self.format["fonteffect"]))
 
    def updateUI(self,fontstyle,fontsize,fonteffect):#For modaless dialog
        self.format["fontstyle"] = fontstyle
        self.format["fontsize"] = fontsize
        self.format["fonteffect"] = fonteffect
 
        self.labelFont = QFont(fontstyle,fontsize)
        self.updateLabel()
 
    def FontModalessDialog(self):
        #仅第一次调用的时候创建对话框,所有可保留对话框的各项设置
        if self.modalessDialog is None:
            self.modalessDialog = FontPropertiesDlg(self)
            #连接从对话框接发出的自定义信号
            self.modalessDialog.applySignal.connect(self.updateUI)
        self.modalessDialog.show()#非模态地显示对话框
 
app = QApplication(sys.argv)
font= MainDialog()
font.show()
app.exec_()