PyQt5 - QLineEdit正则表达式输入验证器
参考：
https://stackoverflow.com/questions/39202697/qt-qlineedit-input-validation
https://stackoverflow.com/questions/15829782/how-to-restrict-user-input-in-qlineedit-in-pyqt
from PyQt5 import QtWidgets, QtCore, QtGui, Qt
import re
############## QLineEdit正则表达式输入验证器
class LineEditRegExpValidator(QtGui.QValidator):
'''
# 默认为科学计数法输入验证器
用法
SciNotValidator = LineEditRegExpValidator() # 创建一个QLineEdit正则表达式输入验证器的类，默认为科学计数法输入验证器
self.LineEdit1.setValidator(SciNotValidator) # 设置验证器（启用）
self.LineEdit1.installEventFilter(SciNotValidator) # QLineEdit清空内容且游标失焦时，自动填充上一次的字符串内容
self.LineEdit2.setValidator(SciNotValidator)
self.LineEdit2.installEventFilter(SciNotValidator)
self.LineEdit3.setValidator(SciNotValidator)
self.LineEdit3.installEventFilter(SciNotValidator)
Validator.validate() is abstract and must be overriddenValidator.validate() is abstract and must be overridden
'''
def __init__(
self,
# 编辑状态框输入结束允许的字符串
fullPatterns=[
r"[+|-]?[0-9]+\.?[0-9]*(?:[Ee][+|-]?[0-9]+)?",
r'[+|-]{0,1}nan', r'[+|-]{0,1}inf'
],
# 编辑状态框输入尚未结束允许的字符串
partialPatterns=[
r'[+|-]?[0-9]+\.?[0-9]*(?:[Ee][+|-]?)?',
r'-',
r'\+',
r'[+|-]{0,1}nan',
r'[+|-]{0,1}na',
r'[+|-]{0,1}n',
r'[+|-]{0,1}inf',
r'[+|-]{0,1}in',
r'[+|-]{0,1}i'
],
fixupString='1.0'
):
super(LineEditRegExpValidator, self).__init__()
self.fullPatterns = fullPatterns
self.partialPatterns = partialPatterns
self.fixupString = fixupString
# 实时监听文本框的改变
# 可能是键盘单个字符'n'输入, 也有可能是粘贴多个字符'nan'输入
def validate(self, string, pos) -> QtGui.QValidator.State: # string为编辑状态框中可见的字符串+输入字符/字符串
# 编辑过程结束，若返回True，将编辑状态框中的字符串填入LineEdit,若返回Flase则自动调用self.fixup方法，将fixup方法返回的字符串填入LineEdit
if self.acceptable_check(string):
#print(f'QtGui.QValidator.Acceptable:{QtGui.QValidator.Acceptable}')
return QtGui.QValidator.Acceptable, string, pos # QtGui.QValidator.Acceptable = 2;
# 编辑过程中允许出现的字符串
if self.intermediate_check(string):
#print(f'QtGui.QValidator.Intermediate:{QtGui.QValidator.Intermediate}')
return QtGui.QValidator.Intermediate, string, pos # QtGui.QValidator.State = 1;
# 编辑过程中不允许出现的字符串(本次输入的单个字符或字符串无效)
else:
#print(f'QtGui.QValidator.Invalid:{QtGui.QValidator.Invalid}')
return QtGui.QValidator.Invalid, string, pos
# 编辑状态框验证通过, 编辑状态框单个字输入符成功
def acceptable_check(self, string) -> bool:
True_ = 0
for fullPattern in self.fullPatterns:
if re.fullmatch(fullPattern, string):
True_ += 1
else:
continue
if True_ != 0:
return True
else:
return False
# 输入还未结束允许的字符串
def intermediate_check(self, string): #-> bool; string为编辑状态框中可见的字符串
"""
Checks if string makes a valid partial float, keeping in mind locale dependent decimal separators.
"""
if string == '':
return True
for partialPattern in self.partialPatterns:
if re.fullmatch(partialPattern, string):
return True
else:
pass
#
def eventFilter(self, lineEdit, event): # -> bool
# FocusIn event
# 每当fous in时，更新LineEditRegExpValidator的fixupString
# 输入验证器
'''
SciNotValidator = LineEditRegExpValidator()
self.LineEdit1.setValidator(SciNotValidator)
self.LineEdit1.installEventFilter(SciNotValidator)
'''
if event.type() == QtCore.QEvent.FocusIn:
# do custom stuff
# print('focus in')
# self.lineEdit_zhuansu.installEventFilter(SciNotValidator)， 在本类中，widget是self.lineEdit，执行函数self.lineEdit.text(), 其它类不一定有text()方法
#lineEdit.selectAll()
QtCore.QTimer.singleShot(0, lineEdit.selectAll) # 0ms
self.fixupString = lineEdit.text()
#print(self.fixupString)
# return False so that the lineEdit will also handle the event
# otherwise it won't focus out
return False
else:
# we don't care about other events
return False
# 重写QValidator的fixup(str)方法。可以在切换焦点后，直接修改不合规则的字符串。参数str是经过validate()方法验证后的字符串；
def fixup(self, string) -> str:
"""
Fixes up input text to create a valid float. Puts an empty string on failure.
"""
print(string)
True_ = 0
for fullPattern in self.fullPatterns:
if re.fullmatch(fullPattern, string):
True_ += 1
else:
continue
if True_ != 0:
return string
else:
return self.fixupString
# listWidget、tableWidget输入数据检查
class LineEditDelegate_Regx(QtWidgets.QStyledItemDelegate):
# 科学计数法正则表达式
regx = r"-?\ *[0-9]+\.?[0-9]*(?:[Ee]\ *-?\ *[0-9]+)?" #
"""
-? optionally matches a negative sign (zero or one negative signs)
\ * matches any number of spaces (to allow for formatting variations like - 2.3 or -2.3)
[0-9]+ matches one or more digits
\.? optionally matches a period (zero or one periods)
[0-9]* matches any number of digits, including zero
(?: ... ) groups an expression, but without forming a "capturing group" (look it up)
[Ee] matches either "e" or "E"
\ * matches any number of spaces (to allow for formats like 2.3E5 or 2.3E 5)
-? optionally matches a negative sign
\ * matches any number of spaces
[0-9]+ matches one or more digits
? makes the entire non-capturing group optional (to allow for the presence or absence of the exponent - 3000 or 3E3
https://stackoverflow.com/questions/18152597/extract-scientific-number-from-string
"""
"""
用法：
def __init__(self, parent=None):
super(NewClassName, self).__init__(parent)
self.setupUi(self)
delegate = LineEditDelegate_Regx(regx=None)
self.listWidget_ShuZhiLieBiao.setItemDelegate(delegate)
self.tableWidget.setItemDelegate(delegate)
"""
def __init__(self, regx=None, parent=None):
super(LineEditDelegate_Regx, self).__init__(parent)
if regx == None:
pass
else:
self.regx = regx
# 方法重写
def createEditor(self, parent, option, index): # self, parent, option, index四个参数均不能少
editor_qlineedit = QtWidgets.QLineEdit(parent)
#SciNotValidator = QtGui.QRegExpValidator(QtCore.QRegExp(self.regx))
SciNotValidator = LineEditRegExpValidator()
editor_qlineedit.setValidator(SciNotValidator)
return editor_qlineedit # LineEditDelegate_Regx(regx=None, parent=None), QStyledItemDelegate(parent: QObject = None)
"""
# LineEdit输入数据检查
def LineEditInputChecking(lineEdit, regx=None):
'''
用法：
LineEditInputChecking(lineEdit=self.lineEdit_zhuansu)
'''
if regx == None:
regx = r"-?\ *[0-9]+\.?[0-9]*(?:[Ee]\ *-?\ *[0-9]+)?"
reg_ex = QtCore.QRegExp(regx)
input_validator = QtGui.QRegExpValidator(reg_ex, lineEdit)
lineEdit.setValidator(input_validator)
"""