我想斷言 PyQt5 信號的身份。具體來說，我想檢查clicked來自給定QPushButton對象的信號是否與存儲在名為 的變量中的信號相同signal。以下代碼段說明了這種情況：from PyQt5.QtWidgets import QApplication, QPushButtonapp = QApplication([])widget = QPushButton()signal = widget.clickedwidget.clicked == signalOut[1]: Falsewidget.clicked is signalOut[2]: Falseid(widget.clicked) == id(signal)Out[3]: False如圖所示，分別涉及==、is和的三個比較id()都產生False，即它們不能斷言左手和右手參數的同一性。有沒有辦法斷言widget.clicked并signal引用相同的信號？
2 回答
慕斯王
TA貢獻1864條經驗 獲得超2個贊
每次調用時都會創建作為實體的信號，因為它們代表不同的連接：
In [1]: import sys
In [2]: from PyQt5 import QtWidgets
In [3]: app = QtWidgets.QApplication(sys.argv)
In [4]: button = QtWidgets.QPushButton()
In [5]: id(button.clicked)
Out[5]: 140150155639464
In [6]: id(button.clicked)
Out[6]: 140150154507528
In [7]: id(button.clicked)
Out[7]: 140150155640184
In [8]: id(button.clicked)
Out[8]: 140150155640504
In [9]: id(button.clicked)
Out[9]: 140150154510128
In [10]: id(button.clicked)
Out[10]: 140149427454320
因此，如果在同一個信號和插槽之間連接 100 次，并且在發出信號時，該插槽將被調用 100 次：
import sys
from PyQt5 import QtCore, QtWidgets
def foo():
print("clicked")
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
button = QtWidgets.QPushButton("Press me")
button.show()
for _ in range(10):
button.clicked.connect(foo)
# the click is emulated
QtCore.QTimer.singleShot(1000, lambda: button.animateClick(500))
QtCore.QTimer.singleShot(2000, app.quit)
sys.exit(app.exec_())
輸出：
clicked
clicked
clicked
clicked
clicked
clicked
clicked
clicked
clicked
clicked
所以直接解決你的問題是不可能的，但我認為你的目標是區分哪個對象發出調用插槽的信號，因為你可能有幾個對象連接到同一個插槽，如果有解決方案：
一、使用sender()方法
如果插槽屬于 QObject（或從 QObject 派生的類作為小部件），那么您可以使用 sender 方法獲取發出信號的對象。
import sys
from PyQt5 import QtCore, QtWidgets
class Widget(QtWidgets.QWidget):
def __init__(self, parent=None):
super(Widget, self).__init__(parent)
self.button_1 = QtWidgets.QPushButton("button 1")
self.button_1.clicked.connect(self.foo)
self.button_2 = QtWidgets.QPushButton("button 2")
self.button_2.clicked.connect(self.foo)
self.button_3 = QtWidgets.QPushButton("button 3")
self.button_3.clicked.connect(self.foo)
lay = QtWidgets.QVBoxLayout(self)
lay.addWidget(self.button_1)
lay.addWidget(self.button_2)
lay.addWidget(self.button_3)
@QtCore.pyqtSlot()
def foo(self):
button = self.sender()
if button is self.button_1:
print("button_1")
elif button is self.button_2:
print("button_2")
elif button is self.button_3:
print("button_3")
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
w = Widget()
w.show()
sys.exit(app.exec_())
2. 將對象作為附加參數傳遞
2.1 拉姆達函數
import sys
from PyQt5 import QtCore, QtWidgets
class Widget(QtWidgets.QWidget):
def __init__(self, parent=None):
super(Widget, self).__init__(parent)
self.button_1 = QtWidgets.QPushButton("button 1")
self.button_1.clicked.connect(lambda *args, b=self.button_1 : self.foo(b))
self.button_2 = QtWidgets.QPushButton("button 2")
self.button_2.clicked.connect(lambda *args, b=self.button_2 : self.foo(b))
self.button_3 = QtWidgets.QPushButton("button 3")
self.button_3.clicked.connect(lambda *args, b=self.button_3 : self.foo(b))
lay = QtWidgets.QVBoxLayout(self)
lay.addWidget(self.button_1)
lay.addWidget(self.button_2)
lay.addWidget(self.button_3)
def foo(self, button):
if button is self.button_1:
print("button_1")
elif button is self.button_2:
print("button_2")
elif button is self.button_3:
print("button_3")
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
w = Widget()
w.show()
sys.exit(app.exec_())
2.1 functools.partial 函數
import sys
from PyQt5 import QtCore, QtWidgets
from functools import partial
class Widget(QtWidgets.QWidget):
def __init__(self, parent=None):
super(Widget, self).__init__(parent)
self.button_1 = QtWidgets.QPushButton("button 1")
self.button_1.clicked.connect(partial(self.foo, self.button_1))
self.button_2 = QtWidgets.QPushButton("button 2")
self.button_2.clicked.connect(partial(self.foo, self.button_2))
self.button_3 = QtWidgets.QPushButton("button 3")
self.button_3.clicked.connect(partial(self.foo, self.button_3))
lay = QtWidgets.QVBoxLayout(self)
lay.addWidget(self.button_1)
lay.addWidget(self.button_2)
lay.addWidget(self.button_3)
def foo(self, button):
if button is self.button_1:
print("button_1")
elif button is self.button_2:
print("button_2")
elif button is self.button_3:
print("button_3")
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
w = Widget()
w.show()
sys.exit(app.exec_())
就我而言，如果可以使用，我更喜歡使用 sender，然后是 functools.partial，最后是 lambda 方法
胡子哥哥
TA貢獻1825條經驗 獲得超6個贊
嘗試一下：
import sys
from PyQt5.QtWidgets import QApplication, QPushButton
app = QApplication([])
def clickButton(w):
# Check what you clicked here. # <-----
return print(w.text())
widget = QPushButton('Button 1')
widget.clicked.connect(lambda : clickButton(widget))
widget2 = QPushButton('Button 2')
widget2.clicked.connect(lambda : clickButton(widget2))
widget.setGeometry(300, 150, 100, 100)
widget.show()
widget2.setGeometry(450, 150, 100, 100)
widget2.show()
sys.exit(app.exec_())
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