PyQt5+python3的FindDialog

 import sys
 from PyQt5.QtWidgets import *
 from PyQt5.QtCore import Qt, pyqtSignal

 class FindDialog(QDialog):
     findNext = pyqtSignal(str, Qt.CaseSensitivity)
     findPrevious = pyqtSignal(str, Qt.CaseSensitivity)

     def __init__(self, parent = None):
         super().__init__(parent)
         self.label = QLabel(self.tr("Find &what:"))
         self.lineEdit = QLineEdit()
         self.label.setBuddy(self.lineEdit)

         self.caseCheckBox = QCheckBox(self.tr("Match &case"))
         self.backwardCheckBox = QCheckBox(self.tr("Search &backward"))

         self.findButton = QPushButton(self.tr("&Find"))
         self.findButton.setDefault(True)
         self.findButton.setEnabled(False)

         self.closeButton = QPushButton(self.tr("Close"))
         self.lineEdit.textChanged.connect(self.enableFindButton)
         self.findButton.clicked.connect(self.findClicked)
         self.closeButton.clicked.connect(self.close)

         self.topLeftLayout = QHBoxLayout()
         self.topLeftLayout.addWidget(self.label)
         self.topLeftLayout.addWidget(self.lineEdit)

         self.leftLayout = QVBoxLayout()
         self.leftLayout.addLayout(self.topLeftLayout)
         self.leftLayout.addWidget(self.caseCheckBox)
         self.leftLayout.addWidget(self.backwardCheckBox)

         self.rightLayout = QVBoxLayout()
         self.rightLayout.addWidget(self.findButton)
         self.rightLayout.addWidget(self.closeButton)
         self.rightLayout.addStretch()

         self.mainLayout = QHBoxLayout()
         self.mainLayout.addLayout(self.leftLayout)
         self.mainLayout.addLayout(self.rightLayout)
         self.setLayout(self.mainLayout)
         self.setWindowTitle(self.tr("Find"))
         self.setFixedHeight(self.sizeHint().height())

     def findClicked(self):
         text = self.lineEdit.text()
         cs = (Qt.CaseSensitive if self.caseCheckBox.isChecked()
               else Qt.CaseInsensitive)

         if self.backwardCheckBox.isChecked():
             self.findPrevious.emit(text, cs)
         else:
             self.findNext.emit(text, cs)

     def enableFindButton(self, text):
         self.findButton.setEnabled(not text == '')

 if __name__ == '__main__':
     app = QApplication(sys.argv)
     dialog = FindDialog()
     dialog.show()
     sys.exit(app.exec())