参考:
https://blog.csdn.net/seniorwizard/article/details/109820641
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import (QApplication, QMainWindow, QMenuBar, QMenu, QAction, QPlainTextEdit, QStyle, QFileDialog,QMessageBox)class DemoNotepad(QMainWindow):def __init__(self, parent=None):super(DemoNotepad, self).__init__(parent) # 设置窗口标题self.setWindowTitle('实战PyQt5: QAction Demo-记事本') # 设置窗口大小self.resize(480, 360)self.path = Noneself.initUi()def initUi(self):#设置一个文本编辑器作为中心小部件self.txtEditor = QPlainTextEdit(self) self.setCentralWidget(self.txtEditor)self.initMenuBar()def initMenuBar(self):menuBar = self.menuBar() fileMenu = menuBar.addMenu('文件(&F)')editMenu = menuBar.addMenu('编辑(&E)')formatMenu = menuBar.addMenu('格式(&O)')helpMenu = menuBar.addMenu('帮助(&H)')style = QApplication.style()# ==== 文件操作部分 ==== ##新建文件aFileNew = QAction('新建(&N)', self)#添加一个图标aFileNew.setIcon(style.standardIcon(QStyle.SP_FileIcon))#添加快捷键aFileNew.setShortcut(Qt.CTRL + Qt.Key_N)aFileNew.triggered.connect(self.onFileNew)fileMenu.addAction(aFileNew) #打开文件aFileOpen = QAction('打开(&O)...', self)aFileOpen.setIcon(style.standardIcon(QStyle.SP_DialogOpenButton))aFileOpen.setShortcut(Qt.CTRL + Qt.Key_O)aFileOpen.triggered.connect(self.onFileOpen)fileMenu.addAction(aFileOpen) #保存aFileSave = QAction('保存(&S)', self) aFileSave.setIcon(style.standardIcon(QStyle.SP_DialogSaveButton)) aFileSave.setShortcut(Qt.CTRL + Qt.Key_S)aFileSave.triggered.connect(self.onFileSave) fileMenu.addAction(aFileSave) #另存为aFileSaveAs = QAction('另存为(&A)...', self)aFileSaveAs.triggered.connect(self.onFileSaveAs)fileMenu.addAction(aFileSaveAs) #间隔线fileMenu.addSeparator() #退出菜单aFileExit = QAction('退出(&X)', self) aFileExit.triggered.connect(self.close)fileMenu.addAction(aFileExit)# ==== 编辑部分 ==== ##撤销编辑aEditUndo = QAction('撤销(&U)',self)aEditUndo.setShortcut(Qt.CTRL + Qt.Key_Z)aEditUndo.triggered.connect(self.txtEditor.undo)editMenu.addAction(aEditUndo)#恢复编辑aEditRedo = QAction('恢复(&R)', self)aEditRedo.setShortcut(Qt.CTRL + Qt.Key_Y)aEditUndo.triggered.connect(self.txtEditor.redo)editMenu.addAction(aEditRedo)#间隔线editMenu.addSeparator() #剪切操作aEditCut = QAction('剪切(&T)', self)aEditCut.setShortcut(Qt.CTRL + Qt.Key_X)aEditCut.triggered.connect(self.txtEditor.cut)editMenu.addAction(aEditCut)#复制操作aEditCopy = QAction('复制(&C)', self)aEditCopy.setShortcut(Qt.CTRL + Qt.Key_C)aEditCopy.triggered.connect(self.txtEditor.copy)editMenu.addAction(aEditCopy)#粘贴操作aEditPaste = QAction('粘贴(&P)', self)aEditPaste.setShortcut(Qt.CTRL + Qt.Key_V)aEditPaste.triggered.connect(self.txtEditor.paste)editMenu.addAction(aEditPaste)#删除操作aEditDel = QAction('删除(&L)', self)aEditDel.setShortcut(Qt.Key_Delete)aEditDel.triggered.connect(self.onEditDelete)editMenu.addAction(aEditDel)#添加分割线editMenu.addSeparator()#全选操作aEditSelectAll = QAction('全选(&A)', self)aEditSelectAll.setShortcut(Qt.CTRL + Qt.Key_A)aEditSelectAll.triggered.connect(self.txtEditor.selectAll)editMenu.addAction(aEditSelectAll)# ==== 格式设置部分 ==== #aFmtAutoLine = QAction('自动换行(&W)', self)aFmtAutoLine.setCheckable(True)aFmtAutoLine.setChecked(True)aFmtAutoLine.triggered[bool].connect(self.onFormatAutoLine)formatMenu.addAction(aFmtAutoLine)# ==== 帮助部分 ==== #aHelpAbout = QAction('关于(&A)...', self)aHelpAbout.triggered.connect(self.onHelpAbout)helpMenu.addAction(aHelpAbout)def msgCritical(self, strInfo):dlg = QMessageBox(self)dlg.setIcon(QMessageBox.Critical)dlg.setText(strInfo)dlg.show()def onFileNew(self):self.txtEditor.clear()def onFileOpen(self):path,_ = QFileDialog.getOpenFileName(self, '打开文件', '', '文本文件 (*.txt)')if path:try:with open(path, 'rU') as f:text = f.read()except Exception as e:self.msgCritical(str(e))else:self.path = pathself.txtEditor.setPlainText(text)def onFileSave(self):if self.path is None:return self.onFileSaveAs()self._saveToPath(self.path)def onFileSaveAs(self):path,_ = QFileDialog.getSaveFileName(self, '保存文件', '', '文本文件 (*.txt)')if not path:returnself._saveToPath(path)def _saveToPath(self, path):text = self.txtEdit.toPlainText()try:with open(path, 'w') as f:f.write(text)except Exception as e:self.msgCritical(str(e))else:self.path = pathdef onEditDelete(self):tc = self.txtEditor.textCursor()#tc.select(QtGui.QTextCursor.BlockUnderCursor) 这样删除一行tc.removeSelectedText()def onFormatAutoLine(self, autoLine):if autoLine:self.txtEditor.setLineWrapMode(QPlainTextEdit.WidgetWidth)else:self.txtEditor.setLineWrapMode(QPlainTextEdit.NoWrap)def onHelpAbout(self):QMessageBox.information(self, '实战PyQt5', 'PyQt5实现的文本编辑器演示版')if __name__ == '__main__':app = QApplication(sys.argv)window = DemoNotepad()window.show()sys.exit(app.exec())