基于来自 DB (SQLITE) 的 Signal 实时更新 QTableView

Question

我有一个非常基本的 PySide2 程序，它使用 sqlite 的数据集库。

我非常简单的布局文件是

# -*- coding: utf-8 -*-

################################################################################
## Form generated from reading UI file 'basic.ui'
##
## Created by: Qt User Interface Compiler version 5.14.2
##
## WARNING! All changes made in this file will be lost when recompiling UI file!
################################################################################

from PySide2.QtCore import (QCoreApplication, QDate, QDateTime, QMetaObject,
    QObject, QPoint, QRect, QSize, QTime, QUrl, Qt)
from PySide2.QtGui import (QBrush, QColor, QConicalGradient, QCursor, QFont,
    QFontDatabase, QIcon, QKeySequence, QLinearGradient, QPalette, QPainter,
    QPixmap, QRadialGradient)
from PySide2.QtWidgets import *


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        if not MainWindow.objectName():
            MainWindow.setObjectName(u"MainWindow")
        MainWindow.resize(1034, 803)
        self.centralwidget = QWidget(MainWindow)
        self.centralwidget.setObjectName(u"centralwidget")
        self.tableWidget = QTableWidget(self.centralwidget)
        if (self.tableWidget.columnCount() < 2):
            self.tableWidget.setColumnCount(2)
        __qtablewidgetitem = QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(0, __qtablewidgetitem)
        __qtablewidgetitem1 = QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(1, __qtablewidgetitem1)
        self.tableWidget.setObjectName(u"tableWidget")
        self.tableWidget.setGeometry(QRect(40, 20, 981, 401))
        self.pushButton = QPushButton(self.centralwidget)
        self.pushButton.setObjectName(u"pushButton")
        self.pushButton.setGeometry(QRect(930, 430, 89, 25))
        MainWindow.setCentralWidget(self.centralwidget)
        self.statusbar = QStatusBar(MainWindow)
        self.statusbar.setObjectName(u"statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)

        QMetaObject.connectSlotsByName(MainWindow)
    # setupUi

    def retranslateUi(self, MainWindow):
        MainWindow.setWindowTitle(QCoreApplication.translate("MainWindow", u"MainWindow", None))
        ___qtablewidgetitem = self.tableWidget.horizontalHeaderItem(0)
        ___qtablewidgetitem.setText(QCoreApplication.translate("MainWindow", u"Name", None));
        ___qtablewidgetitem1 = self.tableWidget.horizontalHeaderItem(1)
        ___qtablewidgetitem1.setText(QCoreApplication.translate("MainWindow", u"Gender", None));
        self.pushButton.setText(QCoreApplication.translate("MainWindow", u"PushButton", None))
    # retranslateUi

我的主文件是

import os

import dataset
from PySide2 import QtWidgets
from PySide2.QtWidgets import QTableWidgetItem

from layouts.basic import Ui_MainWindow

# delete DB to test
try:
    os.remove("data.db")
except:
    pass


class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow) :
    def __init__(self, parent=None) :
        super(MainWindow, self).__init__()

        self.setupUi(self)
        self.showMaximized()

        self.pushButton.pressed.connect(self.upsert)


    def upsert(self):
        db = dataset.connect('sqlite:///data.db')
        table = db['abc']
        for i in range(10):
            table.insert(dict(name='Jane', age=34, gender='female'))

        self.results()

    def results(self) :
        db = dataset.connect('sqlite:///data.db')
        self.tableWidget.setRowCount(0)
        for value in db["abc"] :
            name = value['name']
            gender = value['gender']
            print(gender)

            rowPosition = self.tableWidget.rowCount()
            self.tableWidget.insertRow(rowPosition)
            # self.tableWidget.setSizeAdjustPolicy(
            #     QtWidgets.QAbstractScrollArea.AdjustToContents)
            # self.tableWidget.resizeColumnsToContents()

            self.tableWidget.setItem(rowPosition, 0, QTableWidgetItem(name))
            self.tableWidget.setItem(rowPosition, 1, QTableWidgetItem(gender))


if __name__ == "__main__" :
    app = QtWidgets.QApplication([])
    main_window = MainWindow()
    main_window.show()
    app.exec_()

如您所见，按钮上的主文件创建一个数据库，写入一个名为 abc 的表并插入一些值直到 10 行。完成后，它会调用结果函数并更新表。

现在假设数据已实时写入此数据库，并且每秒不断更新行。

我愿意

1. 当第一行数据可用时通知结果函数
2. 在数据可用时更新 QtableView，而不是在数据加载完成后更新。

我该怎么做？

Answer 1

这就是我解决它的方法。

我实现了一个非常简单的 QFileSystemWatcher

    w = MainWindow()
    paths = ['data.db']
    fs_watcher = QFileSystemWatcher(paths)
    fs_watcher.fileChanged.connect(w.file_changed)

其中 w 是我的 MainWindow 类。

现在，一旦文件实时更新，QfilesystemWatcher 就会通知 file_changed 类

    def file_changed(self) :
        ---Your Logic Here

这为我解决了。