如何将Qlistwidget项目保存在数据库或txt文件中

Question

Hello recently I made app which will I show you below. In pyqt5 I want to save qlistwidget items in txt or in database file but I don't know how to do that and also I want to show automatically saved qlistwidget items in qlistwidget when I will run my app. Also I want to delete selected item from qlistwidget in database and also in qlistwidget Please help me how to do that I have no idea where to start from

I have no idea how to do that

# I am using Pyqt5
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QDialog, QInputDialog, QLineEdit


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        self.MW = MainWindow
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(288, 267)
        MainWindow.setMinimumSize(QtCore.QSize(270, 114))
        MainWindow.setMaximumSize(QtCore.QSize(630, 540))
        MainWindow.setBaseSize(QtCore.QSize(285, 260))
        MainWindow.setLayoutDirection(QtCore.Qt.LeftToRight)
        MainWindow.setStyleSheet("QMainWindow{background-color:#6F2232;}")
        MainWindow.setToolButtonStyle(QtCore.Qt.ToolButtonIconOnly)
        MainWindow.setDocumentMode(False)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setLayoutDirection(QtCore.Qt.LeftToRight)
        self.centralwidget.setStyleSheet("QWidget{background-color:#6F2232;}")
        self.centralwidget.setObjectName("centralwidget")
        self.gridLayout_2 = QtWidgets.QGridLayout(self.centralwidget)
        self.gridLayout_2.setContentsMargins(9, 9, -1, -1)
        self.gridLayout_2.setObjectName("gridLayout_2")
        self.gridLayout = QtWidgets.QGridLayout()
        self.gridLayout.setContentsMargins(0, -1, -1, -1)
        self.gridLayout.setObjectName("gridLayout")
        self.listWidget = QtWidgets.QListWidget(self.centralwidget)
        font = QtGui.QFont()
        font.setPointSize(13)
        self.listWidget.setFont(font)
        self.listWidget.setFocusPolicy(QtCore.Qt.StrongFocus)
        self.listWidget.setAutoFillBackground(False)
        self.listWidget.setStyleSheet("QListWidget{Background-color:#282828;\n"
                                      "color:#FFFFFF}")
        self.listWidget.setFrameShape(QtWidgets.QFrame.StyledPanel)
        self.listWidget.setFrameShadow(QtWidgets.QFrame.Sunken)
        self.listWidget.setLineWidth(1)
        self.listWidget.setModelColumn(0)
        self.listWidget.setObjectName("listWidget")
        self.gridLayout.addWidget(self.listWidget, 0, 0, 1, 1)
        self.gridLayout_2.addLayout(self.gridLayout, 0, 0, 1, 1)
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 288, 21))
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.menubar.sizePolicy().hasHeightForWidth())
        self.menubar.setSizePolicy(sizePolicy)
        self.menubar.setLayoutDirection(QtCore.Qt.LeftToRight)
        self.menubar.setStyleSheet("QMenuBar{background-color:#C3083F;\n"
                                   "color:#FFFFFF}")
        self.menubar.setDefaultUp(False)
        self.menubar.setNativeMenuBar(True)
        self.menubar.setObjectName("menubar")
        self.menuFile = QtWidgets.QMenu(self.menubar)
        font = QtGui.QFont()
        font.setPointSize(9)
        font.setBold(True)
        font.setWeight(75)
        self.menuFile.setFont(font)
        self.menuFile.setLayoutDirection(QtCore.Qt.LeftToRight)
        self.menuFile.setStyleSheet("background-color:#C3083F;\n"
                                    "color:#FFFFFF;")
        self.menuFile.setToolTipsVisible(True)
        self.menuFile.setObjectName("menuFile")
        MainWindow.setMenuBar(self.menubar)
        self.toolBar = QtWidgets.QToolBar(MainWindow)
        self.toolBar.setEnabled(True)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Fixed, QtWidgets.QSizePolicy.Preferred)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.toolBar.sizePolicy().hasHeightForWidth())
        self.toolBar.setSizePolicy(sizePolicy)
        self.toolBar.setFocusPolicy(QtCore.Qt.StrongFocus)
        self.toolBar.setLayoutDirection(QtCore.Qt.LeftToRight)
        self.toolBar.setStyleSheet("QToolBar{background-color:#282828;\n"
                                   "border:#282828;\n"
                                   "padding:2px;}\n")
        self.toolBar.setMovable(True)
        self.toolBar.setAllowedAreas(QtCore.Qt.AllToolBarAreas)
        self.toolBar.setOrientation(QtCore.Qt.Vertical)
        self.toolBar.setIconSize(QtCore.QSize(25, 39))
        self.toolBar.setFloatable(True)
        self.toolBar.setObjectName("toolBar")
        MainWindow.addToolBar(QtCore.Qt.LeftToolBarArea, self.toolBar)
        self.actionAdd = QtWidgets.QAction(MainWindow)
        icon = QtGui.QIcon()
        icon.addPixmap(QtGui.QPixmap(r"C:\Users\User\Desktop\WORK\test\task\plus.png"), QtGui.QIcon.Normal, QtGui.QIcon.Off)
        self.actionAdd.setIcon(icon)
        self.actionAdd.setShortcutContext(QtCore.Qt.WindowShortcut)
        self.actionAdd.setAutoRepeat(True)
        self.actionAdd.setVisible(True)
        self.actionAdd.setMenuRole(QtWidgets.QAction.TextHeuristicRole)
        self.actionAdd.setIconVisibleInMenu(True)
        self.actionAdd.setShortcutVisibleInContextMenu(False)
        self.actionAdd.setObjectName("actionAdd")
        self.actionRemove = QtWidgets.QAction(MainWindow)
        icon1 = QtGui.QIcon()
        icon1.addPixmap(QtGui.QPixmap(r"C:\Users\User\Desktop\WORK\test\task\minus.png"), QtGui.QIcon.Normal, QtGui.QIcon.Off)
        self.actionRemove.setIcon(icon1)
        self.actionRemove.setAutoRepeat(True)
        self.actionRemove.setVisible(True)
        self.actionRemove.setIconVisibleInMenu(True)
        self.actionRemove.setShortcutVisibleInContextMenu(False)
        self.actionRemove.setObjectName("actionRemove")
        self.actionUp = QtWidgets.QAction(MainWindow)
        icon2 = QtGui.QIcon()
        icon2.addPixmap(QtGui.QPixmap(r"C:\Users\User\Desktop\WORK\test\task\up-arrow (1).png"), QtGui.QIcon.Normal, QtGui.QIcon.Off)
        self.actionUp.setIcon(icon2)
        self.actionUp.setAutoRepeat(True)
        self.actionUp.setVisible(True)
        self.actionUp.setIconVisibleInMenu(True)
        self.actionUp.setShortcutVisibleInContextMenu(False)
        self.actionUp.setObjectName("actionUp")
        self.actionDown = QtWidgets.QAction(MainWindow)
        icon3 = QtGui.QIcon()
        icon3.addPixmap(QtGui.QPixmap(r"C:\Users\User\Desktop\WORK\test\task\download.png"), QtGui.QIcon.Normal, QtGui.QIcon.Off)
        self.actionDown.setIcon(icon3)
        self.actionDown.setAutoRepeat(True)
        self.actionDown.setVisible(True)
        self.actionDown.setIconVisibleInMenu(True)
        self.actionDown.setShortcutVisibleInContextMenu(False)
        self.actionDown.setObjectName("actionDown")
        self.actionSort = QtWidgets.QAction(MainWindow)
        icon4 = QtGui.QIcon()
        icon4.addPixmap(QtGui.QPixmap(r"C:\Users\User\Desktop\WORK\test\task\sort (1).png"), QtGui.QIcon.Normal, QtGui.QIcon.Off)
        self.actionSort.setIcon(icon4)
        self.actionSort.setAutoRepeat(True)
        self.actionSort.setVisible(True)
        self.actionSort.setIconVisibleInMenu(True)
        self.actionSort.setShortcutVisibleInContextMenu(False)
        self.actionSort.setObjectName("actionSort")
        self.actionNotepad = QtWidgets.QAction(MainWindow)
        icon5 = QtGui.QIcon()
        icon5.addPixmap(QtGui.QPixmap(":/task/spiral_bound_booklet_64px.png"), QtGui.QIcon.Normal, QtGui.QIcon.Off)
        self.actionNotepad.setIcon(icon5)
        self.actionNotepad.setObjectName("actionNotepad")
        self.menuFile.addAction(self.actionAdd)
        self.menuFile.addAction(self.actionRemove)
        self.menuFile.addAction(self.actionUp)
        self.menuFile.addAction(self.actionDown)
        self.menuFile.addAction(self.actionSort)
        self.menuFile.addAction(self.actionNotepad)
        self.menubar.addAction(self.menuFile.menuAction())
        self.toolBar.addAction(self.actionAdd)
        self.toolBar.addAction(self.actionRemove)
        self.toolBar.addAction(self.actionUp)
        self.toolBar.addAction(self.actionDown)
        self.toolBar.addAction(self.actionSort)
        self.actionAdd.triggered.connect(self.actAdd)
        self.actionRemove.triggered.connect(self.actRemove)
        self.actionUp.triggered.connect(self.actUp)
        self.actionDown.triggered.connect(self.actDown)
        self.actionSort.triggered.connect(self.actSort)
        #self.actionRemove.triggered.connect(self.actEdit)
        self.retranslateUi(MainWindow)

        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.menuFile.setTitle(_translate("MainWindow", "File"))
        self.toolBar.setWindowTitle(_translate("MainWindow", "toolBar"))
        self.actionAdd.setText(_translate("MainWindow", "Add"))
        self.actionRemove.setText(_translate("MainWindow", "Remove"))
        self.actionUp.setText(_translate("MainWindow", "Up"))
        self.actionDown.setText(_translate("MainWindow", "Down"))
        self.actionSort.setText(_translate("MainWindow", "Sort"))
        self.actionNotepad.setText(_translate("MainWindow", "Notepad"))

    #Here when I will trigger this function I want to add item 
    #qlistwidget and also add what I wrote in database or txt file 
    #AUTOMATICALLY. I dont know how to do it please help

    def actAdd(self):
        row = self.listWidget.currentRow()
        QInputDialog.setStyleSheet(self.MW,"QInputDialog{background-color:#C3083F;}")
        text, ok = QInputDialog.getText(self.MW,"Add","Add Task")
        if ok and text is not None:
            self.listWidget.insertItem(row,text)

    # Here I want to remove qlistwidget item and remove it from database or in 
    # txt file too

    def actRemove(self):
        row = self.listWidget.currentRow()
        item = self.listWidget.item(row)
        if item is None:
            return
        else:
            item = self.listWidget.takeItem(row)
            del item

    def actUp(self):
        row = self.listWidget.currentRow()
        if row >=1:
            item = self.listWidget.takeItem(row)
            self.listWidget.insertItem(row -1, item)
            self.listWidget.setCurrentItem(item)

    def actDown(self):
        row = self.listWidget.currentRow()
        if row < self.listWidget.count() -1:
            item = self.listWidget.takeItem(row)
            self.listWidget.insertItem(row +1, item)
            self.listWidget.setCurrentItem(item)

    def actSort(self):
        self.listWidget.sortItems()


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

Answer 1

Instead of writing the data to disk every time you add or remove an entry in the list you could instead only write the data when the app exists. This can be achieved by subclassing QMainWindow and overriding closeEvent like in the example below. In this example the data is saved to save_file.txt . To automatically read in the saved data when the window is initiated you could override MyMainWindow.__init__ , eg

# Ui_MainWindow() as before

class MyMainWindow(QtWidgets.QMainWindow):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)
        self.save_file = 'save_file.txt'
        self.read_from_file(self.save_file)

    def write_to_file(self, file):
        try:
            list_widget = self.ui.listWidget
            entries = '\n'.join(list_widget.item(ii).text() for ii in range(list_widget.count()))
            with open(file, 'w') as fout:
                fout.write(entries)
        except OSError as err:
            print(f"file {file} could not be written")

    def read_from_file(self, file):
        try:
            list_widget = self.ui.listWidget
            with open(file, 'r') as fin:
                entries = [e.strip() for e in fin.readlines()]
            list_widget.insertItems(0, entries)
        except OSError as err:
            with open(file, 'w'):
                pass

    def closeEvent(self, event):
        should_save = QtWidgets.QMessageBox.question(self, "Save data", 
                                                     "Should the data be saved?",
                                                     defaultButton = QtWidgets.QMessageBox.Yes)
        if should_save == QtWidgets.QMessageBox.Yes:
            self.write_to_file(self.save_file)
        return super().closeEvent(event)


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = MyMainWindow()
    MainWindow.show()
    sys.exit(app.exec_())