《PyQt5快速开发与实战》学习笔记。
6 文本框类控件
QLineEdit 类是一个单行文本框控件，可以输入单行字符串。如果需要输入多行字符串，则使用 QTextEdit 类。
6.1 QLineEdit
QLineEdit 类中的常用方法：
定义输入掩码的字符，并说明其如何控制数据输入：
掩码由掩码字符和分隔符字符串组成，后面可以跟一个分号和空白字符，空白字符在编辑后会从文本中删除的。掩码示例如下所示：
QLineEdit 类中的常用信号：
下面创建一个简单的表单：
from PyQt5.QtWidgets import QApplication, QLineEdit, QWidget, QFormLayout
import sys
class lineEditDemo(QWidget):
def __init__(self, parent=None):
super(lineEditDemo, self).__init__(parent)
self.setWindowTitle("QLineEdit例子")
flo = QFormLayout()
pNormalLineEdit = QLineEdit()
pNoEchoLineEdit = QLineEdit()
pPasswordLineEdit = QLineEdit()
pPasswordEchoOnEditLineEdit = QLineEdit()
flo.addRow("Normal", pNormalLineEdit)
flo.addRow("NoEcho", pNoEchoLineEdit)
flo.addRow("Password", pPasswordLineEdit)
flo.addRow("PasswordEchoOnEdit", pPasswordEchoOnEditLineEdit)
pNormalLineEdit.setPlaceholderText("Normal")
pNoEchoLineEdit.setPlaceholderText("NoEcho")
pPasswordLineEdit.setPlaceholderText("Password")
pPasswordEchoOnEditLineEdit.setPlaceholderText("PasswordEchoOnEdit")
# 设置显示效果
pNormalLineEdit.setEchoMode(QLineEdit.Normal)
pNoEchoLineEdit.setEchoMode(QLineEdit.NoEcho)
pPasswordLineEdit.setEchoMode(QLineEdit.Password)
pPasswordEchoOnEditLineEdit.setEchoMode(QLineEdit.PasswordEchoOnEdit)
self.setLayout(flo)
if __name__ == "__main__":
app = QApplication(sys.argv)
win = lineEditDemo()
win.show()
sys.exit(app.exec_())
效果如下：
图1 创建表单
在通常情况下，我们会对用户的输入做一些限制，可以通过验证器来进行。常见的验证器有：整型验证器、浮点型验证器及其他自定义验证器。
from PyQt5.QtWidgets import QApplication, QLineEdit, QWidget, QFormLayout
from PyQt5.QtGui import QIntValidator, QDoubleValidator, QRegExpValidator
from PyQt5.QtCore import QRegExp
import sys
class lineEditDemo(QWidget):
def __init__(self, parent=None):
super(lineEditDemo, self).__init__(parent)
self.setWindowTitle("QLineEdit例子")
flo = QFormLayout()
pIntLineEdit = QLineEdit()
pDoubleLineEdit = QLineEdit()
pValidatorLineEdit = QLineEdit()
flo.addRow("整形", pIntLineEdit)
flo.addRow("浮点型", pDoubleLineEdit)
flo.addRow("字母和数字", pValidatorLineEdit)
pIntLineEdit.setPlaceholderText("整形")
pDoubleLineEdit.setPlaceholderText("浮点型")
pValidatorLineEdit.setPlaceholderText("字母和数字")
# 整形 范围：[1, 99]
pIntValidator = QIntValidator(self)
pIntValidator.setRange(1, 99)
# 浮点型 范围：[-360, 360] 精度：小数点后2位
pDoubleValidator = QDoubleValidator(self)
pDoubleValidator.setRange(-360, 360)
pDoubleValidator.setNotation(QDoubleValidator.StandardNotation)
pDoubleValidator.setDecimals(2)
# 字符和数字
reg = QRegExp("[a-zA-Z0-9]+$")
pValidator = QRegExpValidator(self)
pValidator.setRegExp(reg)
# 设置验证器
pIntLineEdit.setValidator(pIntValidator)
pDoubleLineEdit.setValidator(pDoubleValidator)
pValidatorLineEdit.setValidator(pValidator)
self.setLayout(flo)
if __name__ == "__main__":
app = QApplication(sys.argv)
win = lineEditDemo()
win.show()
sys.exit(app.exec_())
效果：
图2 有验证功能的表单
要限制用户的输入，除了使用验证器，还可以使用输入掩码，常见的有 IP 地址、MAC 地址、日期、许可证号等。
from PyQt5.QtWidgets import QApplication, QLineEdit, QWidget, QFormLayout
import sys
class lineEditDemo(QWidget):
def __init__(self, parent=None):
super(lineEditDemo, self).__init__(parent)
self.setWindowTitle("QLineEdit的输入掩码例子")
flo = QFormLayout()
pIPLineEdit = QLineEdit()
pMACLineEdit = QLineEdit()
pDateLineEdit = QLineEdit()
pLicenseLineEdit = QLineEdit()
pIPLineEdit.setInputMask("000.000.000.000;_")
pMACLineEdit.setInputMask("HH:HH:HH:HH:HH:HH;_")
pDateLineEdit.setInputMask("0000-00-00")
pLicenseLineEdit.setInputMask(">AAAAA-AAAAA-AAAAA-AAAAA-AAAAA;#")
flo.addRow("数字掩码", pIPLineEdit)
flo.addRow("Mac掩码", pMACLineEdit)
flo.addRow("日期掩码", pDateLineEdit)
flo.addRow("许可证掩码", pLicenseLineEdit)
#pIPLineEdit.setPlaceholderText("111")
#pMACLineEdit.setPlaceholderText("222")
#pLicenseLineEdit.setPlaceholderText("333")
#pLicenseLineEdit.setPlaceholderText("444")
self.setLayout(flo)
if __name__ == "__main__":
app = QApplication(sys.argv)
win = lineEditDemo()
win.show()
sys.exit(app.exec_())
效果：
图2 掩码表单
更复杂的例子：
from PyQt5.QtWidgets import QApplication, QLineEdit, QWidget, QFormLayout
from PyQt5.QtGui import QIntValidator, QDoubleValidator, QFont
from PyQt5.QtCore import Qt
import sys
class lineEditDemo(QWidget):
def __init__(self, parent=None):
super(lineEditDemo, self).__init__(parent)
e1 = QLineEdit()
e1.setValidator(QIntValidator())
e1.setMaxLength(4)
e1.setAlignment(Qt.AlignRight)
e1.setFont(QFont("Arial", 20))
e2 = QLineEdit()
e2.setValidator(QDoubleValidator(0.99, 99.99, 2))
flo = QFormLayout()
flo.addRow("integer validator", e1)
flo.addRow("Double validator", e2)
e3 = QLineEdit()
e3.setInputMask('+99_9999_999999')
flo.addRow("Input Mask", e3)
e4 = QLineEdit()
e4.textChanged.connect(self.textchanged)
flo.addRow("Text changed", e4)
e5 = QLineEdit()
e5.setEchoMode(QLineEdit.Password)
flo.addRow("Password", e5)
e6 = QLineEdit("Hello PyQt5")
e6.setReadOnly(True)
flo.addRow("Read Only", e6)
e5.editingFinished.connect(self.enterPress)
self.setLayout(flo)
self.setWindowTitle("QLineEdit例子")
def textchanged(self, text):
print("输入的内容为: "+text)
def enterPress(self):
print("已输入值")
if __name__ == "__main__":
app = QApplication(sys.argv)
win = lineEditDemo()
win.show()
sys.exit(app.exec_())
效果：
图3 复杂的表单
6.3 QTextEdit
QTextEdit 类是一个多行文本框控件，可以显示多行文本内容，当文本内容超出控件显示范围时，可以显示水平个垂直滚动条。QTextEdit 不仅可以显示文本还可以显示HTML文档。
QTextEdit 类中的常用方法：
from PyQt5.QtWidgets import QApplication, QWidget, QTextEdit, QVBoxLayout
import sys
class TextEditDemo(QWidget):
def __init__(self, parent=None):
super(TextEditDemo, self).__init__(parent)
self.setWindowTitle("QTextEdit 例子")
self.resize(300, 270)
self.textEdit = QTextEdit()
layout = QVBoxLayout()
layout.addWidget(self.textEdit)
self.setLayout(layout)
if __name__ == "__main__":
app = QApplication(sys.argv)
win = TextEditDemo()
win.show()
sys.exit(app.exec_())
效果：
图4 文本输入