PyQt5 模态对话框

import sys
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QFont
from PyQt5.QtWidgets import *
#模态对话框，字体选择组合框，按钮盒子
class FontPropertiesDlg(QDialog):
 
    def __init__(self,parent=None):
        super().__init__(parent)
 
        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)
 
        #“确定” “取消” 按钮 可以使用预置的 复合控件 按钮盒子
        '''
        #可以使用内置标准按钮
        buttonBox = QDialogButtonBox(QDialogButtonBox.Ok | QDialogButtonBox.Cancel)
        buttonBox.accepted.connect(self.accept)
        buttonBox.rejected.connect(self.reject)
        '''
        buttonBox = QDialogButtonBox()
        #buttonBox.setOrientation(Qt.Vertical)  # 设为竖向显示，默认为水平方向
        #buttonBox.setStandardButtons(QDialogButtonBox.Ok|QDialogButtonBox.Cancel)
        buttonBox.addButton("确定", QDialogButtonBox.AcceptRole)
        buttonBox.addButton("取消", QDialogButtonBox.RejectRole)
        buttonBox.accepted.connect(self.accept)
        buttonBox.rejected.connect(self.reject)
 
        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.addWidget(buttonBox,2,2)
 
        self.setLayout(layout)
        self.setWindowTitle("字体设置")
 
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)
        FontButton1 = QPushButton("设置字体(模态)")
        self.label = QLabel("默认选择")
        layout = QGridLayout()
        layout.addWidget(FontButton1,0,0)
        layout.addWidget(self.label)
        self.setLayout(layout)
        FontButton1.clicked.connect(self.FontModalDialog)
 
        self.setWindowTitle("模态对话框")
        self.labelFont = QFont(self.format["fontstyle"],self.format["fontsize"])
        self.updateLabel()
    def updateLabel(self):
        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"]))
        self.label.setFont(self.labelFont)
    def updateUI(self):#For modaless dialog
            self.format["fontstyle"] = self.modalessDialog.FontstyleComboBox.currentText()
            self.format["fontsize"] = self.modalessDialog.FontSizeSpinBox.value()
            self.format["fonteffect"] = self.modalessDialog.FontEffectCheckBox.isChecked()
            self.labelFont = QFont(self.format["fontstyle"],self.format["fontsize"])
            self.updateLabel()       
 
    def FontModalDialog(self):
        dialog = FontPropertiesDlg(self) #若使用局部变量，则每次要重新创建
        #dialog.exec_() 会模态化显示对话框，直至关闭它
        if dialog.exec_():#accept 则返回1，reject返回0
            self.format["fontstyle"] = dialog.FontstyleComboBox.currentText()
            self.format["fontsize"] = dialog.FontSizeSpinBox.value()
            self.format["fonteffect"] = dialog.FontEffectCheckBox.isChecked()
            self.labelFont = QFont(self.format["fontstyle"],self.format["fontsize"])
            self.updateLabel()
app = QApplication(sys.argv)
font= MainDialog()
font.show()
app.exec_()