注：import qrc_resources，资源文件resources.qrc如下：
http://s1/mw690/003ytqMFzy78bzZLtks20&690实现多文档界面（MDI）" TITLE="【原创】python3+PyQt5 实现多文档界面（MDI）" />

 sudo pyrcc5 -o qrc_resources.py resources.qrc 生成qrc_resources.py

---

/home/yrd/eric_workspace/chap09/textedit.py


from PyQt5.QtCore import (QFile, QFileInfo, QIODevice,
        QTextStream, Qt)
from PyQt5.QtWidgets import (QFileDialog, QMessageBox, QTextEdit)


class TextEdit(QTextEdit):

    NextId = 1

    def __init__(self, filename="", parent=None):
        super(TextEdit, self).__init__(parent)
        self.setAttribute(Qt.WA_DeleteOnClose)
        self.filename = filename
        if not self.filename:
            self.filename = "Unnamed-{0}.txt".format(
                                    TextEdit.NextId)
            TextEdit.NextId += 1
        self.document().setModified(False)
        self.setWindowTitle(QFileInfo(self.filename).fileName())

    
    def closeEvent(self, event):
        if (self.document().isModified() and
            QMessageBox.question(self,
                   "Text Editor - Unsaved Changes",
                   "Save unsaved changes in {0}?".format(self.filename),
                   QMessageBox.Yes|QMessageBox.No) ==
                QMessageBox.Yes):
            try:
                self.save()
            except EnvironmentError as e:
                QMessageBox.warning(self,
                        "Text Editor -- Save Error",
                        "Failed to save {0}: {1}".format(self.filename, e))


    def isModified(self):
        return self.document().isModified()


    def save(self):
        if self.filename.startswith("Unnamed"):
            filename,filetype = QFileDialog.getSaveFileName(self,
                    "Text Editor -- Save File As", self.filename,
                    "Text files (*.txt *.*)")
            if not filename:
                return
            self.filename = filename
        self.setWindowTitle(QFileInfo(self.filename).fileName())
        exception = None
        fh = None
        try:
            fh = QFile(self.filename)
            if not fh.open(QIODevice.WriteOnly):
                raise IOError(str(fh.errorString()))
            stream = QTextStream(fh)
            stream.setCodec("UTF-8")
            stream << self.toPlainText()
            self.document().setModified(False)
        except EnvironmentError as e:
            exception = e
        finally:
            if fh is not None:
                fh.close()
            if exception is not None:
                raise exception


    def load(self):
        exception = None
        fh = None
        try:
            fh = QFile(self.filename)
            if not fh.open(QIODevice.ReadOnly):
                raise IOError(str(fh.errorString()))
            stream = QTextStream(fh)
            stream.setCodec("UTF-8")
            self.setPlainText(stream.readAll())
            self.document().setModified(False)
        except EnvironmentError as e:
            exception = e
        finally:
            if fh is not None:
                fh.close()
            if exception is not None:
                raise exception

---

/home/yrd/eric_workspace/chap09/texteditor.pyw




import sys
from functools import partial
from PyQt5.QtCore import (QFile, QFileInfo, QSettings, QSignalMapper,
        QTimer,Qt,QByteArray)
from PyQt5.QtWidgets import (QAction, QApplication, QFileDialog,
        QMainWindow, QMessageBox, QTextEdit,QMdiArea,QWidget)
from PyQt5.QtGui import QIcon,QKeySequence
import textedit
import qrc_resources


__version__ = "1.0.0"


class MainWindow(QMainWindow):

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

        self.mdi = QMdiArea()
        self.setCentralWidget(self.mdi)

        fileNewAction = self.createAction("&New", self.fileNew,
                QKeySequence.New, "filenew", "Create a text file")
        fileOpenAction = self.createAction("&Open...", self.fileOpen,
                QKeySequence.Open, "fileopen",
                "Open an existing text file")
        fileSaveAction = self.createAction("&Save", self.fileSave,
                QKeySequence.Save, "filesave", "Save the text")
        fileSaveAsAction = self.createAction("Save &As...",
                self.fileSaveAs, icon="filesaveas",
                tip="Save the text using a new filename")
        fileSaveAllAction = self.createAction("Save A&ll",
                self.fileSaveAll, "filesave",
                tip="Save all the files")
        fileQuitAction = self.createAction("&Quit", self.close,
                "Ctrl+Q", "filequit", "Close the application")
        editCopyAction = self.createAction("&Copy", self.editCopy,
                QKeySequence.Copy, "editcopy",
                "Copy text to the clipboard")
        editCutAction = self.createAction("Cu&t", self.editCut,
                QKeySequence.Cut, "editcut",
                "Cut text to the clipboard")
        editPasteAction = self.createAction("&Paste", self.editPaste,
                QKeySequence.Paste, "editpaste",
                "Paste in the clipboard's text")
        self.windowNextAction = self.createAction("&Next",
                self.mdi.activateNextSubWindow, QKeySequence.NextChild)
        self.windowPrevAction = self.createAction("&Previous",
                self.mdi.activatePreviousSubWindow,
                QKeySequence.PreviousChild)
        self.windowCascadeAction = self.createAction("Casca&de",
                self.mdi.cascadeSubWindows)
        self.windowTileAction = self.createAction("&Tile",
                self.mdi.tileSubWindows)
        self.windowRestoreAction = self.createAction("&Restore All",
                self.windowRestoreAll)
        self.windowMinimizeAction = self.createAction("&Iconize All",
                self.windowMinimizeAll)
        #self.windowArrangeIconsAction = self.createAction(
        #        "&Arrange Icons", self.mdi.arrangeIcons)
        self.windowArrangeIconsAction = self.createAction(
                "&Arrange Icons", self.windowMinimizeAll)        
        self.windowCloseAction = self.createAction("&Close",
                self.mdi.closeActiveSubWindow, QKeySequence.Close)
        self.windowMapper = QSignalMapper(self)
        self.windowMapper.mapped[QWidget].connect(self.mdi.setActiveSubWindow)  
        fileMenu = self.menuBar().addMenu("&File")
        self.addActions(fileMenu, (fileNewAction, fileOpenAction,
                fileSaveAction, fileSaveAsAction, fileSaveAllAction,
                None, fileQuitAction))
        editMenu = self.menuBar().addMenu("&Edit")
        self.addActions(editMenu, (editCopyAction, editCutAction,
                                   editPasteAction))
        self.windowMenu = self.menuBar().addMenu("&Window")
        self.windowMenu.aboutToShow.connect(self.updateWindowMenu)
        fileToolbar = self.addToolBar("File")
        fileToolbar.setObjectName("FileToolbar")
        self.addActions(fileToolbar, (fileNewAction, fileOpenAction,
                                      fileSaveAction))
        editToolbar = self.addToolBar("Edit")
        editToolbar.setObjectName("EditToolbar")
        self.addActions(editToolbar, (editCopyAction, editCutAction,
                                      editPasteAction))

        settings = QSettings()
        if settings.value("MainWindow/Geometry") or settings.value("MainWindow/State"):
            self.restoreGeometry(
                    QByteArray(settings.value("MainWindow/Geometry")))
            self.restoreState(
                    QByteArray(settings.value("MainWindow/State")))

        status = self.statusBar()
        status.setSizeGripEnabled(False)
        status.showMessage("Ready", 5000)

        self.updateWindowMenu()
        self.setWindowTitle("Text Editor")
        QTimer.singleShot(0, self.loadFiles)


    def createAction(self, text, slot=None, shortcut=None, icon=None,
                     tip=None, checkable=False, signal="triggered()"):
        action = QAction(text, self)
        if icon is not None:
            action.setIcon(QIcon(":/{0}.png".format(icon)))
        if shortcut is not None:
            action.setShortcut(shortcut)
        if tip is not None:
            action.setToolTip(tip)
            action.setStatusTip(tip)
        if slot is not None:
            action.triggered.connect(slot)
        if checkable:
            action.setCheckable(True)
        return action


    def addActions(self, target, actions):
        for action in actions:
            if action is None:
                target.addSeparator()
            else:
                target.addAction(action)

    def closeEvent(self, event):
        failures = []
        for textEdit in self.mdi.subWindowList():
            textEdit=textEdit.widget()
            if textEdit.isModified():
                try:
                    textEdit.save()
                except IOError as e:
                    failures.append(str(e))
        if (failures and
            QMessageBox.warning(self, "Text Editor -- Save Error",
                    "Failed to save{0}\nQuit anyway?".format(
                    "\n\t".join(failures)),
                    QMessageBox.Yes|QMessageBox.No) ==
                    QMessageBox.No):
            event.ignore()
            return
        settings = QSettings()
        settings.setValue("MainWindow/Geometry",
                          self.saveGeometry())
        settings.setValue("MainWindow/State",
                          self.saveState())
        files = []
        for textEdit in self.mdi.subWindowList():
            textEdit=textEdit.widget()
            if not textEdit.filename.startswith("Unnamed"):
                files.append(textEdit.filename)
        settings.setValue("CurrentFiles", files)
        self.mdi.closeAllSubWindows()


    def loadFiles(self):
        if len(sys.argv) > 1:
            for filename in sys.argv[1:31]: # Load at most 30 files
                filename = filename
                if QFileInfo(filename).isFile():
                    self.loadFile(filename)
                    QApplication.processEvents()
        else:
            settings = QSettings()
            #files = settings.value("CurrentFiles").toStringList()
            if settings.value("CurrentFiles"):
                files=settings.value("CurrentFiles")
                for filename in files:
                    filename = filename
                    if QFile.exists(filename):
                        self.loadFile(filename)
                        QApplication.processEvents()


    def fileNew(self):
        textEdit = textedit.TextEdit()
        self.mdi.addSubWindow(textEdit)
        textEdit.show()


    def fileOpen(self):
        filename,filetype = QFileDialog.getOpenFileName(self,
                "Text Editor -- Open File")
        if filename:
            for textEdit_MSW in self.mdi.subWindowList():
                textEdit=textEdit_MSW.widget()
                if textEdit.filename == filename:
                    self.mdi.setActiveSubWindow(textEdit_MSW)
                    break
            else:
                self.loadFile(filename)


    def loadFile(self, filename):
        textEdit = textedit.TextEdit(filename)
        try:
            textEdit.load()
        except EnvironmentError as e:
            QMessageBox.warning(self, "Text Editor -- Load Error",
                    "Failed to load {0}: {1}".format(filename, e))
            textEdit.close()
            del textEdit
        else:
            self.mdi.addSubWindow(textEdit)
            textEdit.show()


    def fileSave(self):
        textEdit = self.mdi.activeSubWindow()
        textEdit=textEdit.widget()
        if textEdit is None or not isinstance(textEdit, QTextEdit):
            return True
        try:
            textEdit.save()
            return True
        except EnvironmentError as e:
            QMessageBox.warning(self, "Text Editor -- Save Error",
                    "Failed to save {0}: {1}".format(textEdit.filename, e))
            return False


    def fileSaveAs(self):
        textEdit = self.mdi.activeSubWindow()
        textEdit=textEdit.widget()
        if textEdit is None or not isinstance(textEdit, QTextEdit):
            return
        filename,filetype = QFileDialog.getSaveFileName(self,
                        "Text Editor -- Save File As",
                        textEdit.filename, "Text files (*.txt *.*)")
        if filename:
            textEdit.filename = filename
            return self.fileSave()
        return True


    def fileSaveAll(self):
        errors = []
        for textEdit in self.mdi.subWindowList():
            textEdit=textEdit.widget()
            if textEdit.isModified():
                try:
                    textEdit.save()
                except EnvironmentError as e:
                    errors.append("{0}: {1}".format(textEdit.filename, e))
        if errors:
            QMessageBox.warning(self,
                    "Text Editor -- Save All Error",
                    "Failed to save\n{0}".format("\n".join(errors)))


    def editCopy(self):
        textEdit = self.mdi.activeSubWindow()
        textEdit=textEdit.widget()
        if textEdit is None or not isinstance(textEdit, QTextEdit):
            return
        cursor = textEdit.textCursor()
        text = cursor.selectedText()
        if text:
            clipboard = QApplication.clipboard()
            clipboard.setText(text)


    def editCut(self):
        textEdit = self.mdi.activeSubWindow()
        textEdit=textEdit.widget()
        if textEdit is None or not isinstance(textEdit, QTextEdit):
            return
        cursor = textEdit.textCursor()
        text = cursor.selectedText()
        if text:
            cursor.removeSelectedText()
            clipboard = QApplication.clipboard()
            clipboard.setText(text)


    def editPaste(self):
        textEdit = self.mdi.activeSubWindow()
        textEdit=textEdit.widget()
        if textEdit is None or not isinstance(textEdit, QTextEdit):
            return
        clipboard = QApplication.clipboard()
        textEdit.insertPlainText(clipboard.text())


    def windowRestoreAll(self):
        for textEdit in self.mdi.subWindowList():
            textEdit=textEdit.widget()
            textEdit.showNormal()


    def windowMinimizeAll(self):
        for textEdit in self.mdi.subWindowList():
            textEdit=textEdit.widget()
            textEdit.showMinimized()
    
        
    def updateWindowMenu(self):
        self.windowMenu.clear()
        self.addActions(self.windowMenu, (self.windowNextAction,
                self.windowPrevAction, self.windowCascadeAction,
                self.windowTileAction, self.windowRestoreAction,
                self.windowMinimizeAction,
                self.windowArrangeIconsAction, None,
                self.windowCloseAction))
        textEdits = self.mdi.subWindowList()
        if not textEdits:
            return
        self.windowMenu.addSeparator()
        i = 1
        menu = self.windowMenu
        for textEdit_MSW in textEdits:
            textEdit=textEdit_MSW.widget()
            title = textEdit.windowTitle()
            if i == 10:
                self.windowMenu.addSeparator()
                menu = menu.addMenu("&More")
            accel = ""
            if i < 10:
                accel = "&{0} ".format(i)
            elif i < 36:
                accel = "&{0} ".format(chr(i + ord("@") - 9))
            
            action = menu.addAction("{0}{1}".format(accel, title))
            self.windowMapper.setMapping(action, textEdit_MSW)
            action.triggered.connect(self.windowMapper.map)
            i += 1

if __name__ == "__main__":
    app = QApplication(sys.argv)
    app.setWindowIcon(QIcon(":/icon.png"))
    app.setOrganizationName("Qtrac Ltd.")
    app.setOrganizationDomain("qtrac.eu")
    app.setApplicationName("Text Editor")
    form = MainWindow()
    form.show()
    app.exec_()

运行结果：
http://s16/mw690/003ytqMFzy78bzZMyJN4f&690实现多文档界面（MDI）" TITLE="【原创】python3+PyQt5 实现多文档界面（MDI）" />