如何在 PyQt 中向事件循环发出自定义事件 [英] How to emit custom Events to the Event Loop in PyQt
问题描述
我正在尝试在 PyQt 中发出自定义事件.一个小部件会发出,另一个会监听事件,但这两个小部件不需要关联.
I am trying to emit custom events in PyQt. One widget would emit and another would listen to events, but the two widgets would not need to be related.
在 JavaScript 中,我会这样做
In JavaScript, I would achieve this by doing
// Component 1
document.addEventListener('Hello', () => console.log('Got it'))
// Component 2
document.dispatchEvent(new Event("Hello"))
我知道信号和槽,但只知道如何在父子之间使用它们.我将如何在任意不相关的小部件之间使用这种机制(或其他机制)?
I know about signals and slots, but only know how to use them between parent and child. How would I this mechanism (or other mechanism) between arbitrary unrelated widgets?
推荐答案
在 PyQt 中如下指令:
In PyQt the following instruction:
document.addEventListener('Hello', () => console.log('Got it'))
等价
document.hello_signal.connect(lambda: print('Got it'))
以类似的方式:
document.dispatchEvent(new Event("Hello"))
等价
document.hello_signal.emit()
但是最大的区别是文档"对象的范围,因为连接是在一个全局元素之间.但在 PyQt 中该元素不存在.
But the big difference is the scope of the "document" object, since the connection is between a global element. But in PyQt that element does not exist.
模仿您指出的行为的一种方法是创建一个全局对象:
One way to emulate the behavior that you point out is by creating a global object:
globalobject.py
from PyQt5 import QtCore
import functools
@functools.lru_cache()
class GlobalObject(QtCore.QObject):
def __init__(self):
super().__init__()
self._events = {}
def addEventListener(self, name, func):
if name not in self._events:
self._events[name] = [func]
else:
self._events[name].append(func)
def dispatchEvent(self, name):
functions = self._events.get(name, [])
for func in functions:
QtCore.QTimer.singleShot(0, func)
main.py
from PyQt5 import QtCore, QtWidgets
from globalobject import GlobalObject
class MainWindow(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super().__init__(parent)
button = QtWidgets.QPushButton(text="Press me", clicked=self.on_clicked)
self.setCentralWidget(button)
@QtCore.pyqtSlot()
def on_clicked(self):
GlobalObject().dispatchEvent("hello")
class Widget(QtWidgets.QWidget):
def __init__(self, parent=None):
super().__init__(parent)
GlobalObject().addEventListener("hello", self.foo)
self._label = QtWidgets.QLabel()
lay = QtWidgets.QVBoxLayout(self)
lay.addWidget(self._label)
@QtCore.pyqtSlot()
def foo(self):
self._label.setText("foo")
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
w1 = MainWindow()
w2 = Widget()
w1.show()
w2.show()
sys.exit(app.exec_())
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