pyqt QLineEdit 详细用法
一 QLineEdit回显格式
QLineEdit的文本有四种显示方式：
（1）正常显示，
（2）输入但不显示文本，
（3）密码格式显示，
（4）类似于在linux下输入密码也不显示。
Qt代码中有声明:
NoEcho = 1
Normal = 0
Password = 2
PasswordEchoOnEdit = 3Qt助手的解释
enum QLineEdit::EchoMode
This enum type describes how a line edit should display its contents.
Constant
Value
Description
QLineEdit::Normal
0
Display characters as they are entered. This is the default.
QLineEdit::NoEcho
1
Do not display anything. This may be appropriate for passwords where even the length of the password should be kept secret.
QLineEdit::Password
2
Display platform-dependent password mask characters instead of the characters actually entered.
QLineEdit::PasswordEchoOnEdit
3
Display characters as they are entered while editing otherwise display characters as with Password.
例如下面的demo
代码如下：
from PyQt5.QtWidgets import *
import sys
class QLineEditEchoMode(QWidget) :
def __init__(self):
super(QLineEditEchoMode,self).__init__()
self.initUI()
def initUI(self):
self.setWindowTitle('文本输入框的回显模式')
self.setFixedWidth(290)
formLayout = QFormLayout()
normalLineEdit = QLineEdit()
noEchoLineEdit = QLineEdit()
passwordLineEdit = QLineEdit()
passwordEchoOnEditLineEdit = QLineEdit()
formLayout.addRow("Normal",normalLineEdit)
formLayout.addRow("NoEcho", noEchoLineEdit)
formLayout.addRow("Password",passwordLineEdit)
formLayout.addRow("PasswordEchoOnEdit",passwordEchoOnEditLineEdit)
# 设置lineEdit提示信息
normalLineEdit.setPlaceholderText("文本回显")
noEchoLineEdit.setPlaceholderText("不回显")
passwordLineEdit.setPlaceholderText("密码模式")
passwordEchoOnEditLineEdit.setPlaceholderText("密码不显示")
normalLineEdit.setEchoMode(QLineEdit.Normal)
noEchoLineEdit.setEchoMode(QLineEdit.NoEcho)
passwordLineEdit.setEchoMode(QLineEdit.Password)
passwordEchoOnEditLineEdit.setEchoMode(QLineEdit.NoEcho)
self.setLayout(formLayout)
if __name__ == '__main__':
app = QApplication(sys.argv)
main = QLineEditEchoMode()
main.show()
sys.exit(app.exec_())通过函数setEchoMode设置了QLineEdit的回显模式，setPlaceholderText设置LineEdit的提示信息。
二 QLineEdit输入限制类型
在有些场合，需要限制输入的类型，例如密码不能输入汉字，年龄不能为负数，单科总分不超过150等，那么在开发的时候就需要做一些限制。Qt提供了校验器，可以解决这种限制输入的问题，当然最好的做法还是正则表达式。例如下面的demo:
from PyQt5.QtWidgets import *
from PyQt5.QtGui import QIntValidator,QDoubleValidator, QRegExpValidator
from PyQt5.QtCore import QRegExp
import sys
class QLineEditValidator(QWidget):
def __init__(self):
super(QLineEditValidator,self).__init__()
self.initUI()
def initUI(self):
self.setWindowTitle('校验器')
# 创建表单布局
formLayout = QFormLayout()
intLineEdit = QLineEdit()
doubleLineEdit = QLineEdit()
validatorLineEdit = QLineEdit()
formLayout.addRow('整数类型', intLineEdit)
formLayout.addRow('浮点类型', doubleLineEdit)
formLayout.addRow('数字和字母',validatorLineEdit)
intLineEdit.setPlaceholderText('整型')
doubleLineEdit.setPlaceholderText('浮点型')
validatorLineEdit.setPlaceholderText('字母和数字')
# 整数校验器 [1,99]
intValidator = QIntValidator(self)
intValidator.setRange(1,99)
# 浮点校验器
#设置浮点数为 -180到180，四位小数点，QDoubleValidator有bug, 不建议使用
reg1 = QRegExp('^-?(180|1?[0-7]?\\d(\\.\\d{1,4})?)$')
validator1 = QRegExpValidator(self)
validator1.setRegExp(reg1)
# 字符和数字
reg2 = QRegExp('[a-zA-z0-9]+$')
validator2 = QRegExpValidator(self)
validator2.setRegExp(reg2)
# 设置校验器
intLineEdit.setValidator(intValidator)
doubleLineEdit.setValidator(validator1)
validatorLineEdit.setValidator(validator2)
self.setLayout(formLayout)
if __name__ == '__main__':
app = QApplication(sys.argv)
main = QLineEditValidator()
main.show()
sys.exit(app.exec_())运行结果：
整数限制为1--99
浮点数为 -180到180，四位小数点四种校验器QIntValidator，QDoubleValidator，QRegExpValidator, 和QRegularExpressionValidator。
三 QLineEdit掩码输入
Qt提供了以下掩码输入规定：
A ASCII字母字符是必须输入的(A-Z、a-z) a ASCII字母字符是允许输入的,但不是必需的(A-Z、a-z) N ASCII字母字符是必须输入的(A-Z、a-z、0-9) n ASII字母字符是允许输入的,但不是必需的(A-Z、a-z、0-9) X 任何字符都是必须输入的 x 任何字符都是允许输入的,但不是必需的 9 ASCII数字字符是必须输入的(0-9) 0 ASCII数字字符是允许输入的,但不是必需的(0-9) D ASCII数字字符是必须输入的(1-9) d ASCII数字字符是允许输入的,但不是必需的(1-9) # ASCI数字字符或加减符号是允许输入的,但不是必需的 H 十六进制格式字符是必须输入的(A-F、a-f、0-9) h 十六进制格式字符是允许输入的,但不是必需的(A-F、a-f、0-9) B 二进制格式字符是必须输入的(0,1) b 二进制格式字符是允许输入的,但不是必需的(0,1) > 所有的字母字符都大写 < 所有的字母字符都小写 ! 关闭大小写转换 \ 使用"\"转义上面列出的字符
代码demo如下：
from PyQt5.QtWidgets import *
import sys
class QLineEditMask(QWidget) :
def __init__(self):
super(QLineEditMask,self).__init__()
self.initUI()
def initUI(self):
self.setWindowTitle('用掩码限制QLineEdit控件的输入')
formLayout = QFormLayout()
ipLineEdit = QLineEdit()
macLineEdit = QLineEdit()
dateLineEdit = QLineEdit()
licenseLineEdit = QLineEdit()
# 192.168.123.45
ipLineEdit.setInputMask('000.000.000.000;_')
macLineEdit.setInputMask('HH:HH:HH:HH:HH:HH;_')
dateLineEdit.setInputMask('0000-00-00')
licenseLineEdit.setInputMask('>AAAAA-AAAAA-AAAAA-AAAAA-AAAAA;#')
formLayout.addRow('数字掩码',ipLineEdit)
formLayout.addRow('Mac掩码', macLineEdit)
formLayout.addRow('日期掩码',dateLineEdit)
formLayout.addRow('许可证掩码',licenseLineEdit)
self.setLayout(formLayout)
if __name__ == '__main__':
app = QApplication(sys.argv)
main = QLineEditMask()
main.show()
sys.exit(app.exec_())运行结果：
