PyQt - 如何使用QItemDelegate在表视图中设置QComboBox

Question

我试图在我的表中显示一个组合框,以便我可以从表模型中设置所选索引,就像表中的其他单元格一样.我已经从其他示例拼凑了这些,但仍然无法理解交互如何工作来设置QComboBox的选定索引.

这是我能用来证明问题的最简单的例子.如果有人能演示如何从模型数据中自动设置索引？另外如何使用'currentIndexChanged'信号,因为这似乎在重新绘制时几乎连续不断？谢谢.

# The following tells SIP (the system that binds Qt's C++ to Python)
# to return Python native types rather than QString and QVariant
import sip
sip.setapi('QString', 2)
sip.setapi('QVariant', 2)


from PyQt4 import QtCore, QtGui

class TableModel(QtCore.QAbstractTableModel):
    """
    A simple 5x4 table model to demonstrate the delegates
    """
    def rowCount(self, parent=QtCore.QModelIndex()): return 5
    def columnCount(self, parent=QtCore.QModelIndex()): return 4

    def data(self, index, role=QtCore.Qt.DisplayRole):
        if not index.isValid(): return None
        if not role==QtCore.Qt.DisplayRole: return None
        return "{0:02d}".format(index.row())


class ComboDelegate(QtGui.QItemDelegate):
    """
    A delegate that places a fully functioning QComboBox in every
    cell of the column to which it's applied
    """
    def __init__(self, parent):

        QtGui.QItemDelegate.__init__(self, parent)

    def paint(self, painter, option, index):

        self.combo = QtGui.QComboBox(self.parent())
        self.connect(self.combo, QtCore.SIGNAL("currentIndexChanged(int)"), self.parent().currentIndexChanged)

        li = []
        li.append("Zero")
        li.append("One")
        li.append("Two")
        li.append("Three")
        li.append("Four")
        li.append("Five")

        self.combo.addItems(li)

        if not self.parent().indexWidget(index):
            self.parent().setIndexWidget(
                index, 
                self.combo
            )

class TableView(QtGui.QTableView):
    """
    A simple table to demonstrate the QComboBox delegate.
    """
    def __init__(self, *args, **kwargs):
        QtGui.QTableView.__init__(self, *args, **kwargs)

        # Set the delegate for column 0 of our table
        # self.setItemDelegateForColumn(0, ButtonDelegate(self))
        self.setItemDelegateForColumn(0, ComboDelegate(self))

    @QtCore.pyqtSlot()
    def currentIndexChanged(self, ind):
        print "Combo Index changed {0} {1} : {2}".format(ind, self.sender().currentIndex(), self.sender().currentText())

if __name__=="__main__":
    from sys import argv, exit

    class Widget(QtGui.QWidget):
        """
        A simple test widget to contain and own the model and table.
        """
        def __init__(self, parent=None):
            QtGui.QWidget.__init__(self, parent)

            l=QtGui.QVBoxLayout(self)
            self._tm=TableModel(self)
            self._tv=TableView(self)
            self._tv.setModel(self._tm)
            l.addWidget(self._tv)

    a=QtGui.QApplication(argv)
    w=Widget()
    w.show()
    w.raise_()
    exit(a.exec_())

Answer 1

您使用的paint方法不正确.当您想要更改视图的显示行为时,应该使用它.每次要绘制它时也创建新的小部件非常昂贵.但是您想要更改编辑行为,因此您需要更改程序的整个逻辑.

查看固定代码.下面我将了解变化.

1.首先,我们需要使第一列可编辑.您可以通过重新实现来实现QAbstractItemModel::flags:

def flags(self, index):
    if (index.column() == 0):
        return QtCore.Qt.ItemIsEditable | QtCore.Qt.ItemIsEnabled
    else:
        return QtCore.Qt.ItemIsEnabled

2.默认情况下,当用户执行双击项目时,将创建项目编辑器.如果要默认显示所有组合框,可以使用openPersistentEditor:

for row in range(0, self._tm.rowCount()):
    self._tv.openPersistentEditor(self._tm.index(row, 0))

请注意,您还应该为新创建的单元格(如果有)打开编辑器.

3.现在回到我们的代表处.我们需要实现createEditor在为单元格请求编辑器时视图自动调用的方法:

def createEditor(self, parent, option, index):
    combo = QtGui.QComboBox(parent)
    li = []
    li.append("Zero")
    li.append("One")
    li.append("Two")
    li.append("Three")
    li.append("Four")
    li.append("Five")
    combo.addItems(li)
    self.connect(combo, QtCore.SIGNAL("currentIndexChanged(int)"), 
                 self, QtCore.SLOT("currentIndexChanged()"))
    return combo

注意,connect低于appends,因为我们需要currentIndexChanged在初始化时避免信号.

4.实现setEditorData在模型数据更改时视图将调用的方法.初始化编辑器时也会调用一次.

def setEditorData(self, editor, index):
    editor.blockSignals(True)
    editor.setCurrentIndex(int(index.model().data(index)))
    editor.blockSignals(False)

同样,我们希望避免不是由用户引起的信号,因此我们使用blockSignals.

5.在插槽中,我们只是发出commitData信号,使视图调用setModelData我们的委托:

@QtCore.pyqtSlot()
def currentIndexChanged(self):
    self.commitData.emit(self.sender())

6.实施setModelData方法:

def setModelData(self, editor, model, index):
    model.setData(index, editor.currentIndex())

7.您的模型需要支持数据更改.所以我们应该实现setData模型的方法:

def setData(self, index, value, role=QtCore.Qt.DisplayRole):
    print "setData", index.row(), index.column(), value
    # todo: remember the data