PyQt: 计时器不能从其他线程启动
我正在用Python做一个Qt的图形界面，但遇到了一个错误：QObject::startTimer: 计时器不能从另一个线程启动。这个错误发生在我运行readModemSnap这个方法的时候。我已经花了快一周的时间，尝试了很多网上找到的Qt线程设计模式，但都没有成功。
class ModemScopeWindow(QMainWindow, Ui_ModemScope):
def __init__(self, parent=None):
super(ModemScopeWindow, self).__init__(parent)
# Set up the user interface from Designer.
self.setupUi(self)
self.thread = MainThread()
"""
signal connections
"""
self.thread.newSnap.connect(self.updateScene)
self.thread.updateStatus.connect(self.setStatus)
self.thread.connectionLock.lock()
self.thread.runLock.lock()
self.connect(self.runButton, SIGNAL("clicked()"), self.thread.runLock.unlock, Qt.QueuedConnection)
self.connect(self.connectButton, SIGNAL("clicked()"), self.thread.connectionLock.unlock, Qt.QueuedConnection)
class MainThread(QThread):
newSnap = pyqtSignal(QGraphicsScene)
updateStatus = pyqtSignal(str)
initConnect = pyqtSignal()
def __init__(self, parent = None):
super(MainThread, self).__init__(parent)
self.samples = []
self.connectionLock = QMutex()
self.runLock = QMutex()
self.cliMute = QMutex()
self._displayCrosshairs = True
self._displayGrid = True
self.persistantMode = False
self.sampleDepth = 1
self._currentHaam = "4"
color = QColor(10,255,71)
self.plotPen = QPen(color)
self._leftXscene = -VIEW_SIZE/2
self._topYscene = -VIEW_SIZE/2
self._rightXscene = VIEW_SIZE/2
self._bottomYscene = VIEW_SIZE/2
self._leftXworld = -10.0
self._topYworld = 10.0
self._rightXworld = 10.0
self._bottomYworld = -10.0
self._scene = QGraphicsScene(self._leftXscene, self._topYscene, VIEW_SIZE, VIEW_SIZE, self)
self.start(QThread.HighestPriority)
def run(self):
self.updateStatus.emit("Enter target IP address and press Connect")
self.connectionLock.lock()
self.connectModem()
while(1):
self.runLock.lock()
#compile scene
self.readModemSnap()
self.newSnap.emit(self._scene)
self.runLock.unlock()
def readModemSnap(self):
self.updateStatus.emit("Reading Modem Snap...")
print len(self.samples)
if len(self.samples) >= self.sampleDepth:# and not self.persistantMode:
self.samples.pop(0)
self.cliMute.lock()
temp = cli.getModemSnap()
self.cliMute.unlock()
self.samples.append(temp)
self.cliMute.lock()
modType = cli.modemRead(80)
self.cliMute.unlock()
if((modType | 0x0FFFFFFF) == 0x0FFFFFFF):
modType = "0";
else:
modType = "%x"%modType
modType = str(modType)
modType = "0"
self.updateStatus.emit("Done")
self.refresh()
self._currentHaam = modType[0]
if self._displayGrid:
self.plotModulation(self._currentHaam)
self.handleSnapshotResponse()
self.updateStatus.emit("Ready to Run")
def refresh(self):
#delete scene
items = self._scene.items()
for x in items:
self._scene.removeItem(x)
#repaint the crosshairs
if self._displayCrosshairs:
self.plotLine(-VIEW_SIZE,0,+VIEW_SIZE,0, self.plotPen)
self.plotLine(0, -VIEW_SIZE,0, +VIEW_SIZE, self.plotPen)
self.plotScaleTicks()
#repaint grid
if self._displayGrid:
self.plotModulation(self._currentHaam)
self.newSnap.emit(self._scene)
def handleSnapshotResponse(self):
for x in range(len(self.samples)):
for sample in self.samples[x]:
upper = (sample >> 16) & 0xffff;
lower = sample & 0xffff
if (upper & 0x8000):
upper -= 0x10000
if (lower & 0x8000):
lower -= 0x10000
upper = float(upper)/128.0
lower = float(lower)/128.0
self.plot(upper, lower)
如你所见，我并没有从另一个线程启动任何线程。我是用主线程来启动用户界面，这样会创建一个主线程（MainThread），它在构造时会自己启动。当我注释掉一些代码行以找出问题时，我发现问题出现在readModemSnap方法中调用self.refresh()和self.handleSnapshotResponse()的时候。有没有人能告诉我我哪里做错了？或者有没有关于QThreading的教程？提前谢谢大家。
1 个回答
2
这是一个规则：你不能在除了主线程以外的其他线程中调用任何图形用户界面（GUI）相关的函数。也就是说，只有主线程可以处理这些界面相关的操作。当你看到关于QTimer的错误时，通常是因为界面中的某个地方使用了定时器，而这个定时器却是在其他线程中被触发的。
在你的情况中，最可能的问题是你在工作线程中操作了QGraphicsScene。我建议你调整一下代码，让MainThread.reload这个函数在接收到newSnap信号后再调用，而不是在它之前。