PyQt信号与槽事件机制

• 事件无处不在，默认都有一套事件机制，可以重写来修改事件
• 控件都有自己的信号函数和对应的信号处理函数
• 事件比较隐蔽，一般很难察觉
• 在MVC编辑代码的时候，事件机制很复杂
• qss也是，自有的一套事件机制

import sys
from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import (QWidget, QLCDNumber, QSlider,
    QVBoxLayout, QApplication)


class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()


    def initUI(self):

        lcd = QLCDNumber(self)
        sld = QSlider(Qt.Horizontal, self)

        vbox = QVBoxLayout()
        vbox.addWidget(lcd)
        vbox.addWidget(sld)

        self.setLayout(vbox)
        sld.valueChanged.connect(lcd.display)

        self.setGeometry(300, 300, 250, 150)
        self.setWindowTitle('Signal and slot')
        self.show()


if __name__ == '__main__':

    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

import sys
from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import QWidget, QApplication

class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()


    def initUI(self):

        self.setGeometry(300, 300, 250, 150)
        self.setWindowTitle('Event handler')
        self.show()


    def keyPressEvent(self, e):

        if e.key() == Qt.Key_Escape:
            self.close()


if __name__ == '__main__':

    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

import sys
from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import QWidget, QApplication, QGridLayout, QLabel

class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()


    def initUI(self):

        grid = QGridLayout()
        grid.setSpacing(10)

        x = 0
        y = 0

        self.text = "x: {0},  y: {1}".format(x, y)

        self.label = QLabel(self.text, self)
        grid.addWidget(self.label, 0, 0, Qt.AlignTop)

        self.setMouseTracking(True)

        self.setLayout(grid)

        self.setGeometry(300, 300, 350, 200)
        self.setWindowTitle('Event object')
        self.show()


    def mouseMoveEvent(self, e):

        x = e.x()
        y = e.y()

        text = "x: {0},  y: {1}".format(x, y)
        self.label.setText(text)


if __name__ == '__main__':

    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

import sys
from PyQt5.QtWidgets import QMainWindow, QPushButton, QApplication


class Example(QMainWindow):

    def __init__(self):
        super().__init__()

        self.initUI()


    def initUI(self):

        btn1 = QPushButton("Button 1", self)
        btn1.move(30, 50)

        btn2 = QPushButton("Button 2", self)
        btn2.move(150, 50)

        btn1.clicked.connect(self.buttonClicked)
        btn2.clicked.connect(self.buttonClicked)

        self.statusBar()

        self.setGeometry(300, 300, 290, 150)
        self.setWindowTitle('Event sender')
        self.show()


    def buttonClicked(self):

        sender = self.sender()
        self.statusBar().showMessage(sender.text() + ' was pressed')


if __name__ == '__main__':

    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

自定义信号发射

import sys
from PyQt5.QtCore import pyqtSignal, QObject
from PyQt5.QtWidgets import QMainWindow, QApplication


class Communicate(QObject):

    closeApp = pyqtSignal()


class Example(QMainWindow):

    def __init__(self):
        super().__init__()

        self.initUI()


    def initUI(self):

        self.c = Communicate()
        self.c.closeApp.connect(self.close)

        self.setGeometry(300, 300, 290, 150)
        self.setWindowTitle('Emit signal')
        self.show()


    def mousePressEvent(self, event):

        self.c.closeApp.emit()


if __name__ == '__main__':

    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

import sys

path = "D:/2020"

path in sys.path or sys.path.insert(0, path)

from PySide2 import QtWidgets
from PySide2 import QtGui
from PySide2 import QtCore
import mainWin

class CustomDialog(QtWidgets.QDialog, mainWin.Ui_Dialog):
    def __init__(self, parent=None):
        super(CustomDialog, self).__init__(parent)

        self.setupUi(self)

    @QtCore.Slot()
    def on_pushButton_clicked(self):
        print(100)

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    dialog = CustomDialog()
    dialog.show()
    sys.exit(app.exec_())