如何添加小部件以顯示資料庫中的SQLite資料？-有解無憂

很抱歉這篇文章的長度。我嘗試了大約 10 種不同的方法來解決我的問題，但沒有運氣。我想給出最可能的背景關系。

我是 Pyqt5 的新手。我正在制作一個聯系人應用程式，我能夠使用 pyqt5 GUI 應用程式將資料輸入到 sqlite3 'contacts.db' 檔案中。我在應用程式的左側有 GUI 輸入欄位。我一直卡住的地方是如何在 GUI 應用程式右側的顯示框中顯示“contacts.db”檔案的內容？

這是一個螢屏截圖：如何添加小部件以顯示資料庫中的 SQLite 資料？

到目前為止，這是我的代碼：

import sys
from PyQt5 import  QtWidgets
from PyQt5.QtWidgets import QMainWindow,  QLabel, QLineEdit
from PyQt5.QtWidgets import QPushButton
from PyQt5.QtCore import QSize
from sqlite3 import *  

class MainWindow(QMainWindow):
    
    # Creating Main drop window
    def __init__(self):
        QMainWindow.__init__(self)
        
        # Sets dimentions for main drop window
        self.setMinimumSize(QSize(1000, 425)) 

        # Sets title for main drop window    
        self.setWindowTitle("Contacts") 
        
        def firstname():

            # Creates a label for first field
            self.nameLabel1 = QLabel(self)

            # Creates label text for first label
            self.nameLabel1.setText('First Name: ')

            # Creates first field
            self.line1 = QLineEdit(self)

            # Sets placement for first field
            self.line1.move(95, 50)

            # Sets size for first field
            self.line1.resize(200, 32)

            # Sets placement for first label
            self.nameLabel1.move(20, 50)

        firstname() 

        def lastname():
            self.nameLabel2 = QLabel(self)
            self.nameLabel2.setText('Last Name: ')
            self.line2 = QLineEdit(self)
            self.line2.move(95, 100)
            self.line2.resize(200, 32)
            self.nameLabel2.move(20, 100)
        lastname()

        def email():
            self.nameLabel3 = QLabel(self)
            self.nameLabel3.setText('Email: ')
            self.line3 = QLineEdit(self)
            self.line3.move(95, 150)
            self.line3.resize(200, 32)
            self.nameLabel3.move(20, 150)
        email()

        def phone():
            self.nameLabel4 = QLabel(self)
            self.nameLabel4.setText('Phone: ')
            self.line4 = QLineEdit(self)
            self.line4.move(95, 200)
            self.line4.resize(200, 32)
            self.nameLabel4.move(20, 200)
        phone()
        
        def phone():
            self.nameLabel5 = QLabel(self)
            self.nameLabel5.setText('Location: ')
            self.line5 = QLineEdit(self)
            self.line5.move(95, 250)
            self.line5.resize(200, 32)
            self.nameLabel5.move(20, 250)
        phone()
        
        def button():

            # Creates button, and button label
            pybutton1 = QPushButton('Add Contact', self)

            # Creates framwork for button funtion
            pybutton1.clicked.connect(self.clickMethod1)

            # Sets button size
            pybutton1.resize(200,32)

            # Sets button placement
            pybutton1.move(95, 325)   
        
        button()
    # Creates action that will be preformed when first button is pressed
    def clickMethod1(self):
        conn = connect('Contacts.db')
        c = conn.cursor()
        first = self.line1.text()
        last = self.line2.text()
        email = self.line3.text()
        phone = self.line4.text()
        loc = self.line5.text()

        c.execute(f"""INSERT INTO contacts VALUES('{first}',
        '{last}', '{email}', '{phone}', '{loc}')
        """)
    
        conn.commit()
        conn.close()

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

要制作我擁有的相同資料庫，您可以在 python 中運行它：

from sqlite3 import *

conn = connect('Contacts.db')
c = conn.cursor()

# Make table
def make():
    c.execute("""CREATE TABLE IF NOT EXISTS contacts(
    first TEXT,
    last TEXT,
    email TEXT,
    phone TEXT,
    location TEXT        
    )""")
make()

conn.commit()
conn.close()

非常感謝您的幫助！

uj5u.com熱心網友回復：

Qt 已經通過QtSql模塊提供了對 SQL 的支持，因此您通常不需要使用單獨的 sql 模塊進行通用使用。

資料使用模型加載，并最終使用視圖顯示（閱讀更多關于Qt的模型/視圖編程范例。

您基本上執行以下操作：

加載資料庫引擎；
選擇一個資料庫；
創建一個模型（通常是一個QSqlTableModel）；
創建一個視圖（通常是一個QTableView）；
為該視圖設定模型，使用setModel();

在下面的示例中，您可以看到模型已連接到資料庫，并且由于修改是直接對模型進行的，因此表會隨之自動更新。

^{請注意，我重新撰寫了您的代碼，因為它有很多問題：首先，QMainWindow 應該始終有一個中央小部件，然后您還應該始終使用布局管理器而不是任意大小和位置；我還洗掉了中的函式，__init__因為它們是不必要的，只會使代碼分散注意力。}

from PyQt5 import QtCore, QtWidgets, QtSql

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()
        central = QtWidgets.QWidget()
        mainLayout = QtWidgets.QGridLayout(central)
        mainLayout.setColumnStretch(0, 1)
        mainLayout.setColumnStretch(1, 2)

        formLayout = QtWidgets.QFormLayout()
        mainLayout.addLayout(formLayout, 0, 0)

        self.firstNameEdit = QtWidgets.QLineEdit()
        self.lastNameEdit = QtWidgets.QLineEdit()
        self.emailEdit = QtWidgets.QLineEdit()
        self.phoneEdit = QtWidgets.QLineEdit()
        self.locEdit = QtWidgets.QLineEdit()

        formLayout.addRow('First name:', self.firstNameEdit)
        formLayout.addRow('Last name:', self.lastNameEdit)
        formLayout.addRow('Email:', self.emailEdit)
        formLayout.addRow('Phone:', self.phoneEdit)
        formLayout.addRow('Location:', self.locEdit)

        self.addButton = QtWidgets.QPushButton('Add contact', enabled=False)
        mainLayout.addWidget(self.addButton, 1, 0)

        self.table = QtWidgets.QTableView()
        mainLayout.addWidget(self.table, 0, 1, 2, 1)
        self.table.setEditTriggers(self.table.NoEditTriggers)

        self.setCentralWidget(central)

        db = QtSql.QSqlDatabase.addDatabase('QSQLITE')
        db.setDatabaseName('Contacts.db')
        self.model = QtSql.QSqlTableModel()
        self.model.setTable('contacts')
        self.model.select()
        self.table.setModel(self.model)

        self.mandatoryFields = self.firstNameEdit, self.lastNameEdit
        self.otherFields = self.emailEdit, self.phoneEdit, self.locEdit
        self.allFields = self.mandatoryFields   self.otherFields

        for field in self.allFields:
            field.textChanged.connect(self.validate)

        self.addButton.clicked.connect(self.addRecord)

    def addRecord(self):
        record = self.model.record()
        for i, field in enumerate(self.allFields):
            record.setValue(i, field.text())
        row = self.model.rowCount()
        self.model.insertRow(row)
        self.model.setRecord(row, record)

    def validate(self):
        for field in self.mandatoryFields:
            if not field.text():
                self.addButton.setEnabled(False)
                return
        for field in self.otherFields:
            if field.text():
                break
        else:
            self.addButton.setEnabled(False)
            return
        self.addButton.setEnabled(True)

另請注意，Qt 提供了一個非常方便的類QDataWidgetMapper，它允許將單個小部件與模型的欄位連接起來。通過這種方式，您可以在用戶選擇索引時自動更新欄位，或使用所有欄位更新資料庫。

這是上面代碼的一個稍微修改的版本，實作了映射器（為簡單起見，我再次發布整個代碼，因為修改太復雜了）：

from PyQt5 import QtCore, QtWidgets, QtSql

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()
        central = QtWidgets.QWidget()
        mainLayout = QtWidgets.QGridLayout(central)
        mainLayout.setColumnStretch(0, 1)
        mainLayout.setColumnStretch(1, 2)

        formLayout = QtWidgets.QFormLayout()
        mainLayout.addLayout(formLayout, 0, 0)

        self.firstNameEdit = QtWidgets.QLineEdit()
        self.lastNameEdit = QtWidgets.QLineEdit()
        self.emailEdit = QtWidgets.QLineEdit()
        self.phoneEdit = QtWidgets.QLineEdit()
        self.locEdit = QtWidgets.QLineEdit()

        formLayout.addRow('First name:', self.firstNameEdit)
        formLayout.addRow('Last name:', self.lastNameEdit)
        formLayout.addRow('Email:', self.emailEdit)
        formLayout.addRow('Phone:', self.phoneEdit)
        formLayout.addRow('Location:', self.locEdit)

        self.updateButton = QtWidgets.QPushButton('Update contact', enabled=False)
        self.addButton = QtWidgets.QPushButton('Add contact', enabled=False)
        buttonLayout = QtWidgets.QHBoxLayout()
        buttonLayout.addWidget(self.updateButton)
        buttonLayout.addWidget(self.addButton)
        mainLayout.addLayout(buttonLayout, 1, 0)

        self.table = QtWidgets.QTableView()
        mainLayout.addWidget(self.table, 0, 1, 2, 1)
        self.table.setEditTriggers(self.table.NoEditTriggers)

        self.setCentralWidget(central)

        db = QtSql.QSqlDatabase.addDatabase('QSQLITE')
        db.setDatabaseName('Contacts.db')
        self.model = QtSql.QSqlTableModel()
        self.model.setTable('contacts')
        self.model.select()
        self.table.setModel(self.model)
        self.table.setSelectionMode(self.table.SingleSelection)

        self.mandatoryFields = self.firstNameEdit, self.lastNameEdit
        self.otherFields = self.emailEdit, self.phoneEdit, self.locEdit
        self.allFields = self.mandatoryFields   self.otherFields

        self.mapper = QtWidgets.QDataWidgetMapper()
        self.mapper.setModel(self.model)
        self.mapper.setSubmitPolicy(self.mapper.ManualSubmit)

        for i, field in enumerate(self.allFields):
            field.textChanged.connect(self.validate)
            self.mapper.addMapping(field, i)

        self.addButton.clicked.connect(self.addRecord)
        self.updateButton.clicked.connect(self.updateRecord)
        self.table.selectionModel().selectionChanged.connect(self.selectionChanged)
        self.mapper.currentIndexChanged.connect(self.validate)
        self.table.doubleClicked.connect(self.doubleClicked)
        self.table.viewport().installEventFilter(self)

    def eventFilter(self, obj, event):
        if event.type() == event.MouseButtonPress:
            # clear all fields when clicking on an empty area of the table
            index = self.table.indexAt(event.pos())
            if not index.isValid():
                self.table.selectionModel().select(
                    index, QtCore.QItemSelectionModel.ClearAndSelect)
        return super().eventFilter(obj, event)

    def doubleClicked(self, index):
        widget = self.mapper.mappedWidgetAt(index.column())
        if widget:
            widget.setFocus()

    def selectedRow(self):
        selected = self.table.selectedIndexes()
        if selected:
            return selected[-1].row()
        return -1

    def selectionChanged(self):
        row = self.selectedRow()
        self.mapper.setCurrentIndex(row)
        if row < 0:
            for field in self.allFields:
                field.setText('')
        self.validate()

    def addRecord(self):
        # we cannot use submit(), as it will use the *current* index, nor we can
        # insert the new row and set the new index, as it would clear all fields
        record = self.model.record()
        for i, field in enumerate(self.allFields):
            record.setValue(i, field.text())
        row = self.model.rowCount()
        self.model.insertRow(row)
        self.model.setRecord(row, record)
        self.table.selectionModel().select(self.model.index(row, 0), 
            QtCore.QItemSelectionModel.ClearAndSelect)

    def updateRecord(self):
        row = self.selectedRow()
        if row < 0:
            self.updateButton.setEnabled(False)
            return
        self.mapper.submit()

    def validate(self):
        valid = True
        for field in self.mandatoryFields:
            if not field.text():
                valid = False
                break
        else:
            for field in self.otherFields:
                if field.text():
                    break
            else:
                valid = False
        self.addButton.setEnabled(valid)
        self.updateButton.setEnabled(valid and bool(self.table.selectedIndexes()))

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標籤：Python 蟒蛇-3.x sqlite pyqt5

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