internalPointer方法的工作方式 [英] How internalPointer method works
问题描述
在Car()和Plane()下方的代码中，都是从Base类继承的.
每次单击QTableView时，OnClick()方法都会收到QModelIndex作为其传入参数.
在OnClick()方法范围之内，node=index.internalPointer()行返回在模型的self.items变量中定义的Car或Plane的实例.
模型的self.items不是列表，而是子类的分层变量.但是internalPointer()方法确实使它看起来像是对一个列表变量进行了索引，并为其提供了被单击的QModelIndex行号作为参数.
如果您提供有关internalPointer()方法工作方式的更多详细信息，以便我可以相应地设计Plane，Car和Base类(这样它们将返回我想要的而不是internalPointer().
from PyQt4 import QtCore, QtGui
app=QtGui.QApplication(sys.argv)
class Base(object):
def __init__(self, name, parentNode=None):
self._name = name
self._children=[]
self._parentNode=parentNode
if parentNode is not None:
parentNode.addChild(self)
def typeInfo(self):
return "BaseNode"
def addChild(self, child):
self._children.append(child)
def name(self):
return self._name
def setName(self, name):
self._name = name
def child(self, row):
return self._children[row]
def childCount(self):
return len(self._children)
def getParent(self):
return self._parentNode
def row(self):
if self._parentNode is not None:
return self._parentNode._children.index(self)
class Car(Base):
def __init__(self, name, parent=None):
super(Car, self).__init__(name, parent)
def typeInfo(self):
return "CarNode"
class Plane(Base):
def __init__(self, name, parent=None):
super(Plane, self).__init__(name, parent)
def typeInfo(self):
return "PlaneNode"
class DataModel(QtCore.QAbstractItemModel):
def __init__(self):
QtCore.QAbstractTableModel.__init__(self)
self.items = Base("Base")
car0 = Car("Car0", self.items)
car1 = Car("Car1", car0)
car2 = Car("Car2", car1)
plane0 = Plane("Plane0", self.items)
plane1 = Plane("Plane1", plane0)
plane2 = Plane("Plane2", plane1)
def columnCount(self, index=QtCore.QModelIndex()):
return 3
def getNodeFromIndex(self, index):
if index.isValid():
node = index.internalPointer()
if node:
return node
return self.items
def parent(self, index):
node = self.getNodeFromIndex(index)
parentNode = node.getParent()
if parentNode == self.items:
return QtCore.QModelIndex()
return self.createIndex(parentNode.row(), 0, parentNode)
def index(self, row, column, parentIndex):
parentNode = self.getNodeFromIndex(parentIndex)
childItem = parentNode.child(row)
if childItem:
newIndex=self.createIndex(row, column, childItem)
return newIndex
else:
return QtCore.QModelIndex()
def rowCount(self, parent=QtCore.QModelIndex()):
if not parent.isValid():
parentNode = self.items
else:
parentNode = parent.internalPointer()
return parentNode.childCount()
def data(self, index, role):
if not index.isValid(): return QtCore.QVariant()
row=index.row()
column=index.column()
node=index.internalPointer()
if role==QtCore.Qt.DisplayRole:
if column==0 and not self.columnCount():
return QtCore.QModelIndex()
else:
return QtCore.QModelIndex()
class Window(QtGui.QWidget):
def __init__(self):
super(Window, self).__init__()
mainLayout=QtGui.QHBoxLayout()
self.setLayout(mainLayout)
self.dataModel=DataModel()
self.viewA=QtGui.QTableView()
self.viewA.setModel(self.dataModel)
self.viewA.clicked.connect(self.onClick)
mainLayout.addWidget(self.viewA)
self.show()
def onClick(self, index):
node=index.internalPointer()
print node.name(), node.getParent().name()
window=Window()
sys.exit(app.exec_())
通过相应地设计类尚不清楚您的意思，但内部指针仅是您在QModelIndex中使用createIndex()创建的内容. /p>
请参见 createIndex 的文档.
因此，您可以在其中存储一些有用的东西.
In a code below both Car() and Plane() inherit from Base class.
Every time QTableView is clicked OnClick() method receives a QModelIndex as its incoming argument.
Inside of scope of OnClick() method node=index.internalPointer() line returns an instance of either Car or Plane defined in model's self.items variable.
Model's self.items is not a list but a sub-classed hierarchical variable. Yet internalPointer() method does make it appear it indexes a list variable with the supplied to it as an argument the row number of QModelIndex that was clicked.
I would appreciate if you supply more details on how internalPointer() method works so I could design Plane, Car and Base classes accordingly (so they return what I want and not what internalPointer().
from PyQt4 import QtCore, QtGui
app=QtGui.QApplication(sys.argv)
class Base(object):
def __init__(self, name, parentNode=None):
self._name = name
self._children=[]
self._parentNode=parentNode
if parentNode is not None:
parentNode.addChild(self)
def typeInfo(self):
return "BaseNode"
def addChild(self, child):
self._children.append(child)
def name(self):
return self._name
def setName(self, name):
self._name = name
def child(self, row):
return self._children[row]
def childCount(self):
return len(self._children)
def getParent(self):
return self._parentNode
def row(self):
if self._parentNode is not None:
return self._parentNode._children.index(self)
class Car(Base):
def __init__(self, name, parent=None):
super(Car, self).__init__(name, parent)
def typeInfo(self):
return "CarNode"
class Plane(Base):
def __init__(self, name, parent=None):
super(Plane, self).__init__(name, parent)
def typeInfo(self):
return "PlaneNode"
class DataModel(QtCore.QAbstractItemModel):
def __init__(self):
QtCore.QAbstractTableModel.__init__(self)
self.items = Base("Base")
car0 = Car("Car0", self.items)
car1 = Car("Car1", car0)
car2 = Car("Car2", car1)
plane0 = Plane("Plane0", self.items)
plane1 = Plane("Plane1", plane0)
plane2 = Plane("Plane2", plane1)
def columnCount(self, index=QtCore.QModelIndex()):
return 3
def getNodeFromIndex(self, index):
if index.isValid():
node = index.internalPointer()
if node:
return node
return self.items
def parent(self, index):
node = self.getNodeFromIndex(index)
parentNode = node.getParent()
if parentNode == self.items:
return QtCore.QModelIndex()
return self.createIndex(parentNode.row(), 0, parentNode)
def index(self, row, column, parentIndex):
parentNode = self.getNodeFromIndex(parentIndex)
childItem = parentNode.child(row)
if childItem:
newIndex=self.createIndex(row, column, childItem)
return newIndex
else:
return QtCore.QModelIndex()
def rowCount(self, parent=QtCore.QModelIndex()):
if not parent.isValid():
parentNode = self.items
else:
parentNode = parent.internalPointer()
return parentNode.childCount()
def data(self, index, role):
if not index.isValid(): return QtCore.QVariant()
row=index.row()
column=index.column()
node=index.internalPointer()
if role==QtCore.Qt.DisplayRole:
if column==0 and not self.columnCount():
return QtCore.QModelIndex()
else:
return QtCore.QModelIndex()
class Window(QtGui.QWidget):
def __init__(self):
super(Window, self).__init__()
mainLayout=QtGui.QHBoxLayout()
self.setLayout(mainLayout)
self.dataModel=DataModel()
self.viewA=QtGui.QTableView()
self.viewA.setModel(self.dataModel)
self.viewA.clicked.connect(self.onClick)
mainLayout.addWidget(self.viewA)
self.show()
def onClick(self, index):
node=index.internalPointer()
print node.name(), node.getParent().name()
window=Window()
sys.exit(app.exec_())
It's not exactly clear what you mean by designing your classes accordingly, but internal pointer ist just something you create with help of createIndex() in QModelIndex.
See the documentation of createIndex.
So it's up to you to store something useful in it.
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