PyQt 5事件和信号

信号槽Signals & slots

sld.valueChanged.connect(lcd.display)

# 将滚动条的valueChanged信号连接到lcd的display插槽

 # Author:凌逆战
 # -*- coding:utf-8 -*-
 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)  # 创建一个lcd显示屏对象
         sld = QSlider(Qt.Horizontal, self)  #创建一个水平的滑块

         vbox = QVBoxLayout()    # 创建垂直布局
         vbox.addWidget(lcd) # 在垂直布局中添加lcd显示屏
         vbox.addWidget(sld) # 在垂直布局中添加水平滑块

         self.setLayout(vbox)    # 设置垂直布局
         # 将滑块的valueChanged信号连接到lcd的display插槽
         sld.valueChanged.connect(lcd.display)

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

 if __name__ == '__main__':
     app = QApplication(sys.argv)
     ex = Example()
     sys.exit(app.exec_())

重新实现事件处理器

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

# 重新实现了keyPressEvent()事件处理器

# 键盘按下Escape键会使程序退出

 # Author:凌逆战
 # -*- coding:utf-8 -*-
 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_())

重新实现事件处理器

事件发送者

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

# 两个按钮绑定到同一个插槽

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

# 通过调用sender()方法来判断信号源， 并将其名称显示在窗体的状态栏中。

 # Author:凌逆战
 # -*- coding:utf-8 -*-
 # -*- coding: utf-8 -*-
 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)    # 按钮一Button1
         btn1.move(30, 50)

         btn2 = QPushButton("Button 2", self)    # 按钮二Button2
         btn2.move(150, 50)
         # 两个按钮绑定到一个插槽
         btn1.clicked.connect(self.buttonClicked)    # 按钮一绑定事件
         btn2.clicked.connect(self.buttonClicked)    # 按钮二绑定事件

         self.statusBar()    # 创建一个状态栏

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

     def buttonClicked(self):
         sender = self.sender()  # 通过调用sender()方法来判断信号源
         self.statusBar().showMessage(sender.text() + ' was pressed')

 if __name__ == '__main__':
     app = QApplication(sys.argv)
     ex = Example()
     sys.exit(app.exec_())

事件发送者

发出信号

class Communicate(QObject):
    closeApp = pyqtSignal()

# 创建了一个名为closeApp的信号

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

# 自定义closeApp信号连接到QMainWindow的close槽

def mousePressEvent(self, event):
    self.c.closeApp.emit()

# 当在窗体上点击鼠标时会触发closeApp信号，使程序退出。

 # Author:凌逆战
 # -*- coding:utf-8 -*-
 import sys
 from PyQt5.QtCore import pyqtSignal, QObject
 from PyQt5.QtWidgets import QMainWindow, QApplication
 # 创建一个closeAPP信号
 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) # 自定义closeAPP信号连接到QMainWindow的close槽

         self.setGeometry(300, 300, 290, 150)
         self.setWindowTitle('Emit signal')
         self.show()
     # 重写mousePressEvent函数
     # 当在窗体上点击鼠标时会触发closeAPP信号，是程序退出
     def mousePressEvent(self, event):
         self.c.closeApp.emit()

 if __name__ == '__main__':
     app = QApplication(sys.argv)
     ex = Example()
     sys.exit(app.exec_())

点击鼠标，退出窗口