我是Qt新手。目前，我正试图学习如何从不同的线程更新一个表模型，然后如何为它获得即时的显示更新。我阅读了文档，发现 dataChanged() 和 layoutChanged() 信号。而 dataChanged() 工作正常，任何试图发出 layoutChanged() 失败。
'QObject::connect: Cannot queue arguments of type 'QList<QPersistentModelIndex>' (Make sure 'QList<QPersistentModelIndex>' is registered using qRegisterMetaType().)
搜索这个特殊的错误并没有给我任何可以转化为工作代码的东西。我没有使用任何 QList 或 QPersistentModelIndex 显式，但由于我选择的结构，当然可以隐式使用。
我到底做错了什么？
class TimedModel(QtCore.QAbstractTableModel):
def __init__(self, table, view):
super(TimedModel, self).__init__()
self.table = table
self.view = view
self.setHeaderData(0, Qt.Horizontal, Qt.AlignLeft, Qt.TextAlignmentRole)
self.rows = 6
self.columns = 4
self.step = 5
self.timer = Thread(
name = "Timer",
target = self.tableTimer,
daemon = True)
self.timer.start()
self.random = Random()
self.updated = set()
@staticmethod
def encode(row, column):
return row << 32 | column
def data(self, index, role):
if role == Qt.DisplayRole or role == Qt.EditRole:
return f'Data-{index.row()}-{index.column()}'
if role == Qt.ForegroundRole:
encoded = TimedModel.encode(index.row(), index.column())
return QBrush(Qt.red if encoded in self.updated else Qt.black)
return None
def rowCount(self, index):
return self.rows
def columnCount(self, index):
return self.columns
def headerData(self, col, orientation, role):
if orientation == Qt.Vertical:
# Vertical
return super().headerData(col, orientation, role)
# Horizontal
if not 0 <= col < self.columns:
return None
if role == Qt.DisplayRole:
return f'Data-{col}'
if role == Qt.TextAlignmentRole:
return int(Qt.AlignLeft | Qt.AlignVCenter)
return super().headerData(col, orientation, role)
def tableTimer(self):
while True:
time.sleep(5.0)
randomRow = self.random.randint(0, self.rows)
randomColumn = self.random.randint(0, self.columns)
encodedRandom = TimedModel.encode(randomRow, randomColumn)
if encodedRandom in self.updated:
self.updated.remove(encodedRandom)
else:
self.updated.add(encodedRandom)
updatedIndex = self.createIndex(randomRow, randomColumn)
self.dataChanged.emit(updatedIndex, updatedIndex)
'''this here does not work:'''
self.layoutAboutToBeChanged.emit()
self.rows += self.step
self.layoutChanged.emit()
class MainWindow(QtWidgets.QMainWindow):
def __init__(self):
QtWidgets.QMainWindow.__init__(self)
self.timedTable = QTableView()
self.model = TimedModel(self.timedTable, self)
self.timedTable.setModel(self.model)
headerView = self.timedTable.horizontalHeader()
headerView.setStretchLastSection(True)
self.setCentralWidget(self.timedTable)
self.setGeometry(300, 300, 1000, 600)
self.setWindowTitle('Timed Table')
self.show()
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
app.name = "Timed Table Application"
window = MainWindow()
window.show()
app.exec_()
下面的代码。
self.layoutAboutToBeChanged.emit()
self.rows += self.step
self.layoutChanged.emit()
创建新的模型元素，有 QPersistentModelIndex 在这种情况下，修改该元素是不安全的，因为它意味着从另一个线程修改GUI，所以Qt监控它的创建以警告它的滥用。此处 获取更多信息）。)
所以你会看到那条警告你正在做的事情是不安全的消息。
相反 dataChanged 只发出一个信号，并没有创建任何属于Qt的元素，你已经很幸运了，因为你从一个辅助线程修改一个属于主线程的属性，而没有使用守卫作为mutexes，所以 "self.update "的修改没有产生瓶颈。
Qt指出，GUI和GUI使用的元素只应该在GUI线程中更新，如果你想用其他线程的信息来修改GUI，那么你必须发送这些信息，比如使用线程安全的信号。
import random
import sys
import threading
import time
from PySide2 import QtCore, QtGui, QtWidgets
class TimedModel(QtCore.QAbstractTableModel):
random_signal = QtCore.Signal(object)
def __init__(self, table, view):
super(TimedModel, self).__init__()
self.table = table
self.view = view
self.setHeaderData(
0, QtCore.Qt.Horizontal, QtCore.Qt.AlignLeft, QtCore.Qt.TextAlignmentRole
)
self.rows = 6
self.columns = 4
self.step = 5
self.updated = set()
self.random_signal.connect(self.random_slot)
self.timer = threading.Thread(name="Timer", target=self.tableTimer, daemon=True)
self.timer.start()
@staticmethod
def encode(row, column):
return row << 32 | column
def data(self, index, role):
if role in (QtCore.Qt.DisplayRole, QtCore.Qt.EditRole):
return f"Data-{index.row()}-{index.column()}"
if role == QtCore.Qt.ForegroundRole:
encoded = TimedModel.encode(index.row(), index.column())
return QtGui.QBrush(
QtCore.Qt.red if encoded in self.updated else QtCore.Qt.black
)
return None
def rowCount(self, index):
return self.rows
def columnCount(self, index):
return self.columns
def headerData(self, col, orientation, role):
if orientation == QtCore.Qt.Vertical:
# Vertical
return super().headerData(col, orientation, role)
# Horizontal
if not 0 <= col < self.columns:
return None
if role == QtCore.Qt.DisplayRole:
return f"Data-{col}"
if role == QtCore.Qt.TextAlignmentRole:
return QtCore.Qt.AlignLeft | QtCore.Qt.AlignVCenter
return super().headerData(col, orientation, role)
def tableTimer(self):
while True:
time.sleep(5.0)
randomRow = random.randint(0, self.rows)
randomColumn = random.randint(0, self.columns)
encodedRandom = TimedModel.encode(randomRow, randomColumn)
self.random_signal.emit(encodedRandom)
@QtCore.Slot(object)
def random_slot(self, encodedRandom):
if encodedRandom in self.updated:
self.updated.remove(encodedRandom)
else:
self.updated.add(encodedRandom)
self.layoutAboutToBeChanged.emit()
self.rows += self.step
self.layoutChanged.emit()
class MainWindow(QtWidgets.QMainWindow):
def __init__(self, parent=None):
super().__init__(parent)
self.timedTable = QtWidgets.QTableView()
self.model = TimedModel(self.timedTable, self)
self.timedTable.setModel(self.model)
headerView = self.timedTable.horizontalHeader()
headerView.setStretchLastSection(True)
self.setCentralWidget(self.timedTable)
self.setGeometry(300, 300, 1000, 600)
self.setWindowTitle("Timed Table")
self.show()
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
app.name = "Timed Table Application"
window = MainWindow()
window.show()
app.exec_()