如何让 QIntValidator() 在空时调用 editingFinished？

Question

我有一个带有 QIntValidator 的行编辑小部件：

number_textbox = QLineEdit()
number_textbox.setText("0")
number_textbox.setValidator(QIntValidator())

此外，我将文本框的旧值存储在字典中：

old_val[uid_key] = 0

我希望能够在文本框为空时，如果用户在框外单击或按回车键，将文本框中的文本替换为旧值：

number_textbox.editingFinished.connect(lambda: self.editing_finished_function(number_textbox, old_val[uid_key]))

def editing_finished_function(self, textbox, old_val):
    if textbox.text() == '':
        textbox.setText(old_val)
    else:
        old_val = textbox.text()

不幸的是，QIntValidator() 似乎将空值视为无效，并且从不触发我的函数。有什么方法可以满足我的要求吗？

Answer 1

来自文档：

无效QLineEdit::editingFinished()

This signal is emitted when the Return or Enter key is pressed or the line edit loses focus. Note that if there is a validator() or inputMask() set on the line edit and enter/return is pressed, the editingFinished() signal will only be emitted if the input follows the inputMask() and the validator() returns QValidator::Acceptable.

QIntValidator 似乎不认为空字符串有效。所以我建议您使用 QRegExpValidator

创建自己的验证器

下面是接受数字和空字符串的验证器

regexp = QtCore.QRegExp('(^[0-9]+$|^$)')
validator = QtGui.QRegExpValidator(regexp)

完整示例：

import sys
from PyQt5 import QtWidgets, QtGui, QtCore


class MainWidget(QtWidgets.QWidget):

    old_val = {'val': '0'}

    def __init__(self):
        super(MainWidget, self).__init__()

        self.setLayout(QtWidgets.QVBoxLayout())
        self.setFocusPolicy(QtCore.Qt.ClickFocus)

        regexp = QtCore.QRegExp('(^[0-9]+$|^$)')
        validator = QtGui.QRegExpValidator(regexp)

        number_textbox = QtWidgets.QLineEdit()
        number_textbox.setText(self.old_val['val'])
        number_textbox.setValidator(validator)
        number_textbox.editingFinished.connect(lambda: self.editing_finished_function(number_textbox))

        self.layout().addWidget(number_textbox)

    def editing_finished_function(self, textbox):
        print("FINISHED")
        if textbox.text() == '':
            textbox.setText(self.old_val['val'])

        else:
            self.old_val['val'] = textbox.text()


if __name__ == '__main__':

    app = QtWidgets.QApplication(sys.argv)

    widget = MainWidget()
    widget.show()

    sys.exit(app.exec_())

如何让 QIntValidator() 在空时调用 editingFinished？

How do I make QIntValidator() call editingFinished when empty?

python

pyqt5

qvalidator