Setting custom pushButton as cell widget consumes to much time

Question

The problem is that setCellWidget is just a convenience method: it is not optimized for adding hundreds of widgets to a single table, and so the slow-down in performance that you are seeing is inevitable.

To get the best performance, you will have to create a custom delegate and use QStyle to draw the button in its paint method. Of course, this also means you will have to implement all the mouse-handling and so forth yourself as well.

To give you an idea of what's involved, some example code can be found here.

EDIT:

Here is a test script based on the original code in the question. For me, this completes in a fraction of a second for 325 rows:

import time
from PyQt4 import QtCore, QtGui

class MyPushButton(QtGui.QPushButton):
    def __init__(self, value1, value2, value3, main):
        super(MyPushButton, self).__init__()
        self.__value1   = value1
        self.__value2   = value2
        self.__value3   = value3
        self.__main     = main
        self.connect(self, QtCore.SIGNAL('clicked()'), self, QtCore.SLOT("triggerOutput()"))

    @QtCore.pyqtSlot()
    def triggerOutput(self):
        self.__main.emit(QtCore.SIGNAL("DoSomethingSignal(PyQt_PyObject, PyQt_PyObject, PyQt_PyObject)"), self.__value1 , self.__value2 , self.__value3)

class Window(QtGui.QWidget):
    def __init__(self):
        QtGui.QWidget.__init__(self)
        self.table = QtGui.QTableWidget(self)
        self.button = QtGui.QPushButton('Populate', self)
        self.button.clicked.connect(self.handleButton)
        layout = QtGui.QVBoxLayout(self)
        layout.addWidget(self.table)
        layout.addWidget(self.button)

    def handleButton(self):
        self.populateTable(325)

    def populateTable(self, numberOfRows):
        self.table.setVisible(0)
        self.table.setSortingEnabled(0)
        self.table.setRowCount(numberOfRows)
        self.table.setColumnCount(10)

        for i in range(0, numberOfRows):
            for colNum in range(10):
                text = 'Text(%d, %d)' % (i, colNum)
                self.table.setItem(i, colNum, QtGui.QTableWidgetItem(text))
            button = MyPushButton(1, 2, 3, self)
            button.setText("Click")
            startTime = time.time()
            self.table.setCellWidget(i,9, button)
            print i," self.tableWidget.setCellWidget(i,9, button) time: ", time.time() - startTime

        self.table.resizeColumnsToContents()
        self.table.setSortingEnabled(1)
        self.table.sortByColumn(0, QtCore.Qt.AscendingOrder)
        self.table.setVisible(1)

if __name__ == '__main__':

    import sys
    app = QtGui.QApplication(sys.argv)
    window = Window()
    window.setGeometry(600, 300, 1000, 600)
    window.show()
    sys.exit(app.exec_())

UPDATE:

I'm not sure exactly what you want, but the row resizing issue can probably be resolved by setting the resize-mode to Fixed before populating the table, and then setting it to ResizeToContents afterwards:

    ...
    self.tableWidget.horizontalHeader().setResizeMode(QtGui.QHeaderView.Fixed)
    self.tableWidget.verticalHeader().setResizeMode(QtGui.QHeaderView.Fixed)

    # populate table

    self.table.verticalHeader().setResizeMode(QtGui.QHeaderView.ResizeToContents)
    self.table.resizeColumnsToContents()
    self.tableWidget.setSortingEnabled(1)
    self.tableWidget.sortByColumn(0, QtCore.Qt.AscendingOrder)

Setting custom pushButton as cell widget consumes to much time

EDIT 2 vvvvv

^^^^^