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import sysimport randomimport tracebackfrom PyQt5 import QtWidgets, QtCore, QtGuiclass QLabelDemo(QtWidgets.QWidget):    def __init__(self):        super(QLabelDemo, self).__init__()        try:            self.setFixedSize(800, 400)            # 创建4个标签            self.label = MyQLabel(self)            # setText():设置Qlabel的文本内容            self.label.setText('这是一个文本标签\n这是一个QLabel控件')            self.label.setFrameShape(QtWidgets.QFrame.Box)            self.label.setFixedSize(370, 370)            vbox1 = QtWidgets.QVBoxLayout()            vbox1.addWidget(self.label)            self.labels = []            self.comboxs = []            self.sliders = []            self.lineedits = []            self.pushbuttons = []            self.labels.append(QtWidgets.QLabel('Alignment'))            infomation1 = ["AlignLeft", "AlignRight", "AlignHCenter", "AlignJustify",                           "AlignTop", "AlignBottom", "AlignVCenter", "AlignBaseline",                           "AlignCenter"]            self.comboxs.append(QtWidgets.QComboBox(self))            self.comboxs[-1].addItems(infomation1)            self.comboxs[-1].activated[str].connect(self.change_alignment)            self.labels.append(QtWidgets.QLabel('indent'))            self.sliders.append(QtWidgets.QSlider(QtCore.Qt.Horizontal))            self.sliders[-1].valueChanged.connect(self.change_indent)            self.sliders[-1].setRange(-1, 400)            self.lineedits.append(QtWidgets.QLineEdit())            self.lineedits[-1].setText(str(self.sliders[-1].value()))            self.lineedits[-1].setMaximumWidth(40)            # check1 = QtWidgets.QCheckBox('dd')            self.labels.append(QtWidgets.QLabel('margin'))            self.sliders.append(QtWidgets.QSlider(QtCore.Qt.Horizontal))            self.sliders[-1].valueChanged.connect(self.change_margin)            self.sliders[-1].setRange(0, 400)            self.lineedits.append(QtWidgets.QLineEdit())            self.lineedits[-1].setText(str(self.sliders[-1].value()))            self.lineedits[-1].setMaximumWidth(40)            self.labels.append(QtWidgets.QLabel('pixmap'))            self.pushbuttons.append(QtWidgets.QPushButton('set pixmap'))            self.pushbuttons[-1].setCheckable(True)            self.pushbuttons[-1].clicked.connect(self.change_pixmap)            self.labels.append(QtWidgets.QLabel('Scaled Contents'))            self.pushbuttons.append(QtWidgets.QPushButton('set Scaled Contents'))            self.pushbuttons[-1].setCheckable(True)            self.pushbuttons[-1].clicked.connect(self.change_scaled_contents)            self.labels.append(QtWidgets.QLabel('TextInteractionFlags'))            self.pushbuttons.append(QtWidgets.QPushButton('set TextInteractionFlags'))            self.pushbuttons[-1].setCheckable(True)            self.pushbuttons[-1].clicked.connect(self.change_TextInteractionFlags)            self.labels.append(QtWidgets.QLabel('has selected text'))            self.lineedits.append(QtWidgets.QLineEdit())            self.lineedits[-1].setText('')            self.labels.append(QtWidgets.QLabel('text'))            infomation2 = ["QLabel用于显示文本或图像。没有提供用户交互功能。标签的视觉外观可以以各种方式配置，并且可以用于为另一个小部件指定焦点助记键。",                           "
This is a heading
"]            self.comboxs.append(QtWidgets.QComboBox(self))            self.comboxs[-1].addItems(infomation2)            self.comboxs[-1].activated[str].connect(self.change_text)            self.labels.append(QtWidgets.QLabel('WordWrap'))            self.pushbuttons.append(QtWidgets.QPushButton('set WordWrap'))            self.pushbuttons[-1].setCheckable(True)            self.pushbuttons[-1].clicked.connect(self.change_WordWrap)            self.labels.append(QtWidgets.QLabel('&Buddy'))            self.pushbuttons.append(QtWidgets.QPushButton('set Buddy'))            self.pushbuttons[-1].setCheckable(True)            self.pushbuttons[-1].clicked.connect(self.change_Buddy)            self.lineedits.append(QtWidgets.QLineEdit())            self.lineedits[-1].setText('Alt + B')            self.labels.append(QtWidgets.QLabel('&Puddy'))            self.pushbuttons[-1].setCheckable(True)            self.pushbuttons[-1].clicked.connect(self.change_Buddy)            self.lineedits.append(QtWidgets.QLineEdit())            self.lineedits[-1].setText('Alt + P')            self.pushbuttons.append(QtWidgets.QPushButton('Enable mouseTracking'))            self.pushbuttons[-1].setCheckable(True)            self.pushbuttons[-1].clicked.connect(self.change_mouseTracking)            grid = QtWidgets.QGridLayout()            grid.addWidget(self.labels[0], 0, 0, 1, 2)            grid.addWidget(self.comboxs[0], 0, 2, 1, 3)            grid.addWidget(self.labels[1], 1, 0, 1, 2)            grid.addWidget(self.sliders[0], 1, 2, 1, 2)            grid.addWidget(self.lineedits[0], 1, 4, 1, 1)            grid.addWidget(self.labels[2], 2, 0, 1, 2)            grid.addWidget(self.sliders[1], 2, 2, 1, 2)            grid.addWidget(self.lineedits[1], 2, 4, 1, 1)            grid.addWidget(self.labels[3], 3, 0, 1, 2)            grid.addWidget(self.pushbuttons[0], 3, 2, 1, 3)            grid.addWidget(self.labels[4], 4, 0, 1, 2)            grid.addWidget(self.pushbuttons[1], 4, 2, 1, 3)            grid.addWidget(self.labels[5], 5, 0, 1, 2)            grid.addWidget(self.pushbuttons[2], 5, 2, 1, 3)            grid.addWidget(self.labels[6], 6, 0, 1, 2)            grid.addWidget(self.lineedits[2], 6, 2, 1, 3)            grid.addWidget(self.labels[7], 7, 0, 1, 2)            grid.addWidget(self.comboxs[1], 7, 2, 1, 3)            grid.addWidget(self.labels[8], 8, 0, 1, 2)            grid.addWidget(self.pushbuttons[3], 8, 2, 1, 3)            grid.addWidget(self.labels[9], 9, 0, 1, 2)            grid.addWidget(self.pushbuttons[4], 9, 2, 2, 2)            grid.addWidget(self.lineedits[3], 9, 4, 1, 1)            grid.addWidget(self.labels[10], 10, 0, 1, 2)            grid.addWidget(self.lineedits[4], 10, 4, 1, 1)            grid.addWidget(self.pushbuttons[5], 11, 0, 1, 5)            # 垂直布局相关属性设置            hbox = QtWidgets.QHBoxLayout()            # 添加标签到垂直布局中            hbox.addLayout(vbox1)            hbox.addLayout(grid)            hbox.setStretch(0, 8)            hbox.setStretch(0, 1)            # hbox.addLayout(vbox3)            # 加载布局：前面设置好的垂直布局            self.setLayout(hbox)            # 设置标题            self.setWindowTitle('Qlabel例子')        except Exception as e:            traceback.print_exc()    def change_alignment(self, txt):        if txt == 'AlignLeft':            self.label.setAlignment(QtCore.Qt.AlignLeft)        if txt == 'AlignRight':            self.label.setAlignment(QtCore.Qt.AlignRight)        if txt == 'AlignHCenter':            self.label.setAlignment(QtCore.Qt.AlignHCenter)        if txt == 'AlignJustify':            self.label.setAlignment(QtCore.Qt.AlignJustify)        if txt == 'AlignTop':            self.label.setAlignment(QtCore.Qt.AlignTop)        if txt == 'AlignBottom':            self.label.setAlignment(QtCore.Qt.AlignBottom)        if txt == 'AlignVCenter':            self.label.setAlignment(QtCore.Qt.AlignVCenter)        if txt == 'AlignBaseline':            self.label.setAlignment(QtCore.Qt.AlignBaseline)        if txt == 'AlignCenter':            self.label.setAlignment(QtCore.Qt.AlignCenter)    def change_indent(self, value):        self.label.setIndent(value)        self.lineedits[0].setText(str(self.sliders[0].value()))    def change_margin(self, value):        self.label.setMargin(value)        self.lineedits[1].setText(str(self.sliders[1].value()))    def change_pixmap(self):        try:            if self.pushbuttons[0].isChecked():                p = QtGui.QPixmap()                p.load("./images/key154px_capslock.png")                self.label.setPixmap(p)            else:                self.label.setText('这是一个文本标签\n这是一个QLabel控件')        except Exception as e:            print(e)    def change_scaled_contents(self):        if self.pushbuttons[1].isChecked():            self.label.setScaledContents(True)        else:            self.label.setScaledContents(False)    def change_TextInteractionFlags(self):        try:            if self.pushbuttons[2].isChecked():                self.label.setTextInteractionFlags(QtCore.Qt.TextSelectableByMouse)            else:                self.label.setTextInteractionFlags(QtCore.Qt.NoTextInteraction)        except Exception as e:            traceback.print_exc()    def check_state(self):        while True:            if self.label.hasSelectedText():                self.lineedits[2].setText(self.label.selectedText())            QtWidgets.QApplication.processEvents(QtCore.QEventLoop.AllEvents, 100)    def change_text(self, str):        self.label.setText(str)    def change_WordWrap(self):        if self.pushbuttons[3].isChecked():            self.label.setWordWrap(True)        else:            self.label.setWordWrap(False)    def change_Buddy(self):        try:            if self.pushbuttons[4].isChecked():                self.labels[9].setBuddy(self.lineedits[3])                self.labels[10].setBuddy(self.lineedits[4])            else:                self.labels[9].setBuddy(None)                self.labels[10].setBuddy(None)        except Exception as e:            traceback.print_exc()    def change_mouseTracking(self):        if self.pushbuttons[5].isChecked():            self.label.setMouseTracking(True)        else:            self.label.setMouseTracking(False)class MyQLabel(QtWidgets.QLabel):    def __init__(self, parent=None):        super(MyQLabel, self).__init__(parent)    #   右键菜单    def contextMenuEvent(self, event):        try:            self.setText('QLabel打开右键菜单事件')            Context = QtWidgets.QMenu()            Context.addAction('cut')            Context.addAction('copy')            Context.exec_(event.globalPos())        except Exception as e:            traceback.print_exc()    #  由于qlable默认无法选中，需要打开TextInteractionFlags    def focusInEvent(self, event):        try:            self.setText('QLabel获得焦点事件')        except Exception as e:            traceback.print_exc()    def focusOutEvent(self, event):        try:            self.setText('QLabel失去焦点事件')        except Exception as e:            traceback.print_exc()    #   必须获得焦点后才能捕获到key    def keyPressEvent(self, event):        self.setText(str(event.key()))    #   必须按键拖动才会触发，打开mouseTracking可以任意捕获    def mouseMoveEvent(self, event):        try:            self.setText('全局位置：' + str(event.globalPos()) +  # 屏幕左上角                         '\n局部位置：' + str(event.localPos()) +  # 控件左上角                         '\n屏幕位置：' + str(event.screenPos()) +  # 和全局位置一样                         '\n窗口位置：' + str(event.windowPos()))  # 界面左上角        except Exception as e:            traceback.print_exc()    def mousePressEvent(self, event):        self.setText('鼠标点击事件' + str(event.button()) + str(event.globalPos()))    def mouseReleaseEvent(self, event):        self.setText('鼠标松开事件' + str(event.button()) + str(event.globalPos()))    #   重写paintEvent会直接清空界面，需要重新绘制    # def paintEvent(self, event):    #     try:    #         print('paintEvent 触发')    #         self.setText('paintEvent 触发')    #     except Exception as e:    #         traceback.print_exc()if __name__ == '__main__':    app = QtWidgets.QApplication(sys.argv)    win = QLabelDemo()    win.show()    win.check_state()    sys.exit(app.exec_())