PyQt5快速开发与实战 4.3 QLabel and 4.4 文本框类控件

PyQt5快速开发与实战

4. 第4章 PyQt5 基本窗口控件

4.3 QLabel

4.3.1 QLabel介绍

QLabel对象作为一个占位符可以显示不可编辑的文本或图片，也可以放置一GIF 动画，还可以被用作提示标记为其他控件。纯文本、链接或富文本可以显示标签上。

QLabel是界面中的标签类，它继承自QFrame类。QLabel类的继承结构：

QObject → QPaintDevice → Qwidget → QFrame → QLabel

4.3.2 Qlabel类中的常用方法：

4.3.3 QLabel类的常用信号

4.3.4 显示QLabel标签案例

from PyQt5.QtWidgets import QApplication,QLabel,QWidget,QVBoxLayout
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QPixmap ,QPalette
import sys

class WindowDemo(QWidget):
    def __init__(self):
        super().__init__()

        label1 = QLabel(self)
        label2 = QLabel(self)
        label3 = QLabel(self)
        label4 = QLabel(self)

        # 初始化标签控件
        label1.setText("这是一个文本标签。")
        label1.setAutoFillBackground(True)
        palette = QPalette()
        palette.setColor(QPalette.Window , Qt.blue)
        label1.setPalette(palette)
        label1.setAlignment(Qt.AlignCenter) ## 设置文本标签居中显示

        label2.setText("欢迎使用Python GUI应用")

        label3.setAlignment(Qt.AlignCenter)
        label3.setToolTip("这是一个图片标签")
        label3.setPixmap(QPixmap("../打包资源文件/pic/python.jpg"))

        label4.setText("欢迎访问丁家雄的博客主页")

        label4.setAlignment(Qt.AlignRight)
        label4.setToolTip("这是一个超链接标签")

        # 在窗口布局中添加控件
        vbox = QVBoxLayout()
        vbox.addWidget(label1)
        vbox.addStretch()
        vbox.addWidget(label2)
        vbox.addStretch()
        vbox.addWidget(label3)
        vbox.addStretch()
        vbox.addWidget(label4)

        ## 允许label1 控件访问超链接
        label1.setOpenExternalLinks(True)
        # 允许label4 控件访问超链接
        label4.setOpenExternalLinks(True)

        # 点击 文本框 绑定槽事件
        label4.linkActivated.connect(link_clicked)

        ##滑过文本框 绑定 槽事件

        label2.linkHovered.connect(link_hovered)
        label1.setTextInteractionFlags(Qt.TextSelectableByMouse)

        self.setLayout(vbox)
        self.setWindowTitle("QLabel案例")

def link_hovered():
    print("当用鼠标滑过 label 1-2 标签时，触发事件。")

def link_clicked():
    print("当用鼠标滑过 label -4 标签时，触发事件。")


if __name__ == '__main__':
    from pyqt5_plugins.examples.exampleqmlitem import QtCore
    QtCore.QCoreApplication.setAttribute(QtCore.Qt.AA_EnableHighDpiScaling)
    app = QApplication(sys.argv)
    win = WindowDemo()
    win.show()
    sys.exit(app.exec_())
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4.3.5 QLabel标签快捷键的使用案例

from PyQt5.QtWidgets import *
import sys

class QlableDemo(QDialog):
    def __init__(self):
        super().__init__()

        self.setWindowTitle("QLabel例子")
        nameLb1 = QLabel('&Name',self)
        nameEd1 = QLineEdit(self)
        nameLb1.setBuddy(nameEd1) # 设置伙伴

        nameLb2 = QLabel('&Password',self)
        nameEd2 = QLineEdit(self)
        nameLb2.setBuddy(nameEd2)

        btnOK = QPushButton('&Ok')
        btnCancel = QPushButton('&Cancel')
        mainLayout = QGridLayout(self)
        mainLayout.addWidget(nameLb1,0,0)
        mainLayout.addWidget(nameEd1,0,1,1,2)

        mainLayout.addWidget(nameLb2,1,0)
        mainLayout.addWidget(nameEd2,1,1,1,2)

        mainLayout.addWidget(btnOK,2,1)
        mainLayout.addWidget(btnCancel,2,2)

if __name__ == '__main__':
    from pyqt5_plugins.examples.exampleqmlitem import QtCore
    QtCore.QCoreApplication.setAttribute(QtCore.Qt.AA_EnableHighDpiScaling)
    app = QApplication(sys.argv)
    win = QlableDemo()
    win.show()
    sys.exit(app.exec_())
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4.4 文本框类控件

4.4.1 QLineEdit

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。

QLineEdit类中的常用方法：

输入掩码的占位符和字面字符

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：

QLineEdit类中的常用信号：

4.4.2 案例——EchoMode的显示效果

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案例")

        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__':
    from pyqt5_plugins.examples.exampleqmlitem import QtCore
    QtCore.QCoreApplication.setAttribute(QtCore.Qt.AA_EnableHighDpiScaling)
    app = QApplication(sys.argv)
    win = lineEditDemo()
    win.show()
    sys.exit(app.exec_())
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4.4.3 案例——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验证器案例")

        flo = QFormLayout()
        pIntLineEdit = QLineEdit()
        pDoubleLineEdit = QLineEdit()
        pValidatorLineEdit = QLineEdit()

        flo.addRow("整型",pIntLineEdit)
        flo.addRow("浮点型",pDoubleLineEdit)
        flo.addRow("字母和数字",pValidatorLineEdit)

        pIntLineEdit.setPlaceholderText("整型")
        pDoubleLineEdit.setPlaceholderText("浮点型")
        pValidatorLineEdit.setPlaceholderText("字母和数字")

        # 整型，范围:[1,99]
        pIntValidator = QIntValidator(self)
        pIntValidator.setRange(1,99)

        # 浮点型 ，范围：[-360,360]，精度：小数点后两位
        pDoubleValidator = QDoubleValidator(self)
        pDoubleValidator.setRange(-360,360)
        pDoubleValidator.setNotation(QDoubleValidator.StandardNotation)
        pDoubleValidator.setDecimals(2)

        # 字母和数字
        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__':
    from pyqt5_plugins.examples.exampleqmlitem import QtCore
    QtCore.QCoreApplication.setAttribute(QtCore.Qt.AA_EnableHighDpiScaling)
    app = QApplication(sys.argv)
    win = lineEditDemo()
    win.show()
    sys.exit(app.exec_())
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4.4.4 案例——输入掩码

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输入掩码案例")

        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)

        self.setLayout(flo)

if __name__ == '__main__':
    from pyqt5_plugins.examples.exampleqmlitem import QtCore
    QtCore.QCoreApplication.setAttribute(QtCore.Qt.AA_EnableHighDpiScaling)
    app = QApplication(sys.argv)
    win = lineEditDemo()
    win.show()
    sys.exit(app.exec_())
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4.4.5 综合示例

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 DingJiaxiong")
        e6.setReadOnly(True)
        flo.addRow("Read Only",e6)

        e5.editingFinished.connect(self.enterPress)
        self.setLayout(flo)
        self.setWindowTitle("QLineEdit综合示例")

    def textchanged(self,text):
        print("输入的内容为：" + text)

    def enterPress(self):
        print("已输入值")

if __name__ == '__main__':
    from pyqt5_plugins.examples.exampleqmlitem import QtCore
    QtCore.QCoreApplication.setAttribute(QtCore.Qt.AA_EnableHighDpiScaling)
    app = QApplication(sys.argv)
    win = lineEditDemo()
    win.show()
    sys.exit(app.exec_())
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4.4.5 【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类中常用方法

4.4.6 案例——多行文本框QTextEdit的使用

from PyQt5.QtWidgets import QApplication , QWidget,QTextEdit ,QVBoxLayout,QPushButton
import sys

class TextEditDemo(QWidget):
    def __init__(self,parent = None):
        super(TextEditDemo, self).__init__(parent)
        self.setWindowTitle("QTextEdit案例")

        self.resize(300 , 270)
        self.textEdit = QTextEdit()
        self.btnPress1 = QPushButton("显示文本")
        self.btnPress2 = QPushButton("显示HTML")

        layout = QVBoxLayout()
        layout.addWidget(self.textEdit)
        layout.addWidget(self.btnPress1)
        layout.addWidget(self.btnPress2)

        self.setLayout(layout)
        self.btnPress1.clicked.connect(self.btnPress1_Clicked)
        self.btnPress2.clicked.connect(self.btnPress2_Clicked)

    def btnPress1_Clicked(self):
        self.textEdit.setPlainText("Hello DingJiaxiong!\n单击按钮")

    def btnPress2_Clicked(self):
        self.textEdit.setHtml("Hello DingJiaxiong!\n单击按钮。")

if __name__ == '__main__':
    from pyqt5_plugins.examples.exampleqmlitem import QtCore
    QtCore.QCoreApplication.setAttribute(QtCore.Qt.AA_EnableHighDpiScaling)
    app = QApplication(sys.argv)
    win = TextEditDemo()
    win.show()
    sys.exit(app.exec_())
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