如何在 PyQt5 QLineEdit 中的金额字段中允许空格，同时限制其他非数字输入

Question

我正在使用 PyQt5 开发费用管理应用程序，我需要在金额字段中允许空格，同时限制其他非数字输入。我的目标是使用户能够输入多个金额，并用空格分隔。我已经实现了一个事件过滤器来限制输入，但我在允许空格以及数字和小数点时遇到问题。

这是我的代码的相关部分：

class ExpenseManager(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()
        self.setup_ui()
        self.install_event_filters()

    def setup_ui(self):
        # Setup UI components (simplified for brevity)
        self.amount = QtWidgets.QLineEdit(self)
        self.itemName = QtWidgets.QLineEdit(self)
        self.date = QtWidgets.QDateEdit(self)
        self.note = QtWidgets.QTextEdit(self)
        self.accountDropdown = QtWidgets.QComboBox(self)
        self.statusBar = QtWidgets.QStatusBar(self)
        self.setStatusBar(self.statusBar)
        # Additional UI setup...

    def add_expense(self):
        amount_text = self.amount.text()
        item = self.itemName.text().upper()
        date = self.date.date().toString('yyyy-MM-dd')
        time = datetime.now().strftime("%H:%M:%S")
        note = self.note.toPlainText().upper()
        account = self.accountDropdown.currentText()

        if amount_text and item and account:
            amounts = amount_text.split()
            try:
                # Check if all amounts are valid numbers
                amounts = [float(amount) for amount in amounts]
                
                self.c.execute("SELECT id, name FROM accounts WHERE name = ?", (account,))
                account_row = self.c.fetchone()

                if account_row:
                    account_id = account_row[0]
                    account_on = account_row[1]

                    for amount in amounts:
                        self.c.execute("INSERT INTO expenses (amount, item, date, time, note, account_on, account_id) VALUES (?, ?, ?, ?, ?, ?, ?)", 
                                    (amount, item, date, time, note, account_on, account_id))
                    
                    self.conn.commit()
                    if self.completer_note:
                        self.completer_note.model().setStringList(self.get_notes())
                    self.amount.clear()
                    self.itemName.clear()
                    self.date.setDate(QtCore.QDate.currentDate())
                    self.note.clear()
                    self.statusBar.showMessage("Expense(s) added successfully", 3000)
                    self.amount.setFocus()
                else:
                    self.statusBar.showMessage("Selected account does not exist", 3000)
            except ValueError:
                self.statusBar.showMessage("Please enter valid amount(s)", 3000)
        else:
            self.statusBar.showMessage("Please fill all mandatory(*) fields", 3000)

        self.completer.model().setStringList(self.get_items())
        self.completer_note.model().setStringList(self.get_notes())  

    def install_event_filters(self):
        self.amount.installEventFilter(self)
        self.itemName.installEventFilter(self)
        self.note.installEventFilter(self)
        self.date.lineEdit().installEventFilter(self)

    def eventFilter(self, obj, event):
        if event.type() == QtCore.QEvent.KeyPress:
            if event.key() == QtCore.Qt.Key_Return or event.key() == QtCore.Qt.Key_Enter:
                if obj == self.date.lineEdit():
                    self.add_expense()
                    return True
                elif obj == self.note:
                    if event.modifiers() & QtCore.Qt.ControlModifier:
                        return False
                    else:
                        self.add_expense()
                        return True
                elif obj == self.itemName:
                    if event.key() == QtCore.Qt.Key_Return or event.key() == QtCore.Qt.Key_Enter:
                        if self.itemName.completer().popup().isVisible():
                            return False
                        else:
                            self.add_expense()
                            return True
            if isinstance(obj, QtWidgets.QLineEdit) or isinstance(obj, QtWidgets.QTextEdit):
                if event.text().isalpha():
                    obj.insert(event.text().upper())
                    return True
        return super().eventFilter(obj, event)

在 eventFilter 中，我尝试在下面添加此行，但没有成功：

if event.text() == ' ' or event.text().isalnum():
    obj.insert(event.text())
    return True

使用此代码，我尝试在金额字段中允许数字、空格和小数点。但是，该代码没有按预期工作。金额字段仍然不接受空格。

我应该进行哪些更改才能确保金额字段允许空格，同时限制其他非数字输入？

如有任何帮助，我们将不胜感激。谢谢！

Answer 1

此类任务的通常解决方案是QValidator。例如，以下正则表达式允许带有可选前导和尾随空格的正整数：

amount.setValidator(QRegularExpressionValidator(QRegularExpression("(\s?)+[0-9]+(\s?)+")))

其他字段也可能具有以下日期和时间模板：

date.setValidator(QRegularExpressionValidator(QRegularExpression("[0-9]{0,4}-[0-9]{0,2}-[0-9]{0,2}")))
time.setValidator(QRegularExpressionValidator(QRegularExpression("[0-9]{0,2}:[0-9]{0,2}:[0-9]{0,2}")))