Python PySide中的信号在被计时器调用时不发出
我需要定期发出信号。定时器执行特定的功能,发出我想要的信号。由于某些原因,此函数未被发出。我能够在最少的代码中重现错误(请参阅下文)。如果我在没有计时器的情况下也这样做,一切都会正常工作:Python PySide中的信号在被计时器调用时不发出,python,qt,pyside,Python,Qt,Pyside,我需要定期发出信号。定时器执行特定的功能,发出我想要的信号。由于某些原因,此函数未被发出。我能够在最少的代码中重现错误(请参阅下文)。如果我在没有计时器的情况下也这样做,一切都会正常工作: from threading import Timer import time from PySide import QtCore class testSignals(QtCore.QObject): signal = QtCore.Signal(); def __init__(self):
from threading import Timer
import time
from PySide import QtCore
class testSignals(QtCore.QObject):
signal = QtCore.Signal();
def __init__(self):
QtCore.QObject.__init__(self)
def run(self):
self.signal.emit()
class testConnection():
@QtCore.Slot()
def receiveMe(self):
print('Signal received')
# signal is emmited when data is changed
def __init__(self):
test = testSignals()
test.signal.connect(self.receiveMe)
test.run();
test = testConnection()
我能够用以下代码重现我的问题:
from threading import Timer
import time
from PySide import QtCore
class testSignals(QtCore.QObject):
signal = QtCore.Signal();
def __init__(self):
self.is_running = False
QtCore.QObject.__init__(self)
self.start()
def emitMe(self):
self.is_running = False
self.start()
# print("emitMe")
self.signal.emit()
def start(self):
if not self.is_running:
self._timer = Timer(0.2, self.emitMe)
self._timer.start()
self.is_running = True
def stop(self):
self._timer.cancel()
self.is_running = False
class testConnection():
@QtCore.Slot()
def receiveMe(self):
print('Signal received')
# signal is emmited when data is changed
def __init__(self):
test = testSignals()
test.signal.connect(self.receiveMe)
test.start();
time.sleep(2.0)
test.stop();
test = testConnection()
“接收到信号”一词不会在屏幕上打印出来 正如@ekhumaro在评论中所说,QTimer帮了大忙。我需要一个事件循环。我发布代码是为了让答案有效。我用QTimer重写了它,这让一切变得更简单。注意,我需要调用QCoreApplication来运行线程。同样,这只是复制我需要做的事情的最小代码
import time
from PySide import QtCore
from probeConnection import ProbeConnection
class testSignals(QtCore.QObject):
def __init__(self):
self.timer = QtCore.QTimer()
self.timer.timeout.connect(self.tick)
self.start()
def tick(self):
print("tick")
def getData(self):
return time.strftime('%H:%M:%S')
def start(self):
self.timer.start(1000)
def stop(self):
self.timer.stop()
class testConnection():
def receiveMe(self):
print('time: ' + self.test.getData())
def __init__(self):
self.test = testSignals()
self.test.timer.timeout.connect(self.receiveMe)
app = QtCore.QCoreApplication([])
test = testConnection()
timer = QtCore.QTimer()
timer.singleShot(4000,app.exit)
app.exec_()
它产生:
tick
time: 13:23:37
tick
time: 13:23:38
tick
time: 13:23:39
tick
time: 13:23:40
没有事件循环信号就不能工作。你能详细说明一下吗?我认为这是因为线程不在Qt的控制范围内,但我还没有找到解决方法。我将介绍一下:对于直接信号/插槽连接,不需要事件循环(甚至不需要应用程序对象)。但是对于跨线程连接,信号被发布到事件队列并进行异步处理。当然,您可能需要使用
QThread
来实现这一点,尽管我认为可能会有一些变通方法(不要问我如何)。但不管怎样:为什么不使用QTimer
?