In PyQt, I am looking for a way to set the height of rows in a QTreeView
(similarly to QTableView.setRowHeight(row, row_height)
, but QTreeView
does not have this function). QAbstractItemModel
is used to set the tree model. I read some suggestions here using and sub-classing QAbstractItemDelegate.sizeHint(option, index)
but I don't know exactly how to call them correctly within my tree model.
Any minimal code or suggestion would be greatly appreciated. Thanks.
The QTreeView
works out a height for each row based on the data and size hints returned for each item. I think you probably just need to return size hints, either for all your items, or at least the first row (if you have setUniformRowHeights(True)
). Incidentally this can significantly improve performance and so you should set it if you can.
So you just need to implement your AbstractItemModel.data()
method to return a size hint in the SizeHintRole
. Something like this:
def data(self, index, role = QtCore.Qt.DisplayRole):
# Check the index, possibly return None
if role == QtCore.Qt.DisplayRole:
# Return the data
elif role == QtCore.Qt.SizeHintRole:
return QtCore.QSize(item_width,item_height)
# Other roles - maybe return None if you don't use them.
EDIT: Big example
You say you are still having trouble so here is a complete working example, based on the standard QT itemviews example. Try varying the QSize returned in the data method to see how the view changes:
import sys
from PySide import QtCore,QtGui
class TreeItem(object):
def __init__(self, data, parent=None):
self.parentItem = parent
self.data = data
self.childItems = []
def appendChild(self, item):
self.childItems.append(item)
def row(self):
if self.parentItem:
return self.parentItem.childItems.index(self)
return 0
class TreeModel(QtCore.QAbstractItemModel):
def __init__(self, parent=None):
super(TreeModel, self).__init__(parent)
self.rootItem = TreeItem(None)
for i,c in enumerate("abcdefg"):
child = TreeItem([i,c],self.rootItem)
self.rootItem.appendChild(child)
parent = self.rootItem.childItems[1]
child = TreeItem(["down","down"],parent)
parent.appendChild(child)
def columnCount(self, parent):
return 2
def data(self, index, role):
if not index.isValid():
return None
if role == QtCore.Qt.DisplayRole:
item = index.internalPointer()
return item.data[index.column()]
elif role == QtCore.Qt.SizeHintRole:
print "giving size hint"
return QtCore.QSize(40,40)
return None
def flags(self, index):
if not index.isValid():
return QtCore.Qt.NoItemFlags
return QtCore.Qt.ItemIsEnabled | QtCore.Qt.ItemIsSelectable
def headerData(self, section, orientation, role):
if orientation == QtCore.Qt.Horizontal and role == QtCore.Qt.DisplayRole:
return ["A","B"][section]
return None
def index(self, row, column, parent):
if not self.hasIndex(row, column, parent):
return QtCore.QModelIndex()
if not parent.isValid():
parentItem = self.rootItem
else:
parentItem = parent.internalPointer()
childItem = parentItem.childItems[row]
if childItem:
return self.createIndex(row, column, childItem)
else:
return QtCore.QModelIndex()
def parent(self, index):
if not index.isValid():
return QtCore.QModelIndex()
parentItem = index.internalPointer().parentItem
if parentItem == self.rootItem:
return QtCore.QModelIndex()
return self.createIndex(parentItem.row(), 0, parentItem)
def rowCount(self, parent):
if parent.column() > 0:
return 0
if not parent.isValid():
parentItem = self.rootItem
else:
parentItem = parent.internalPointer()
return len(parentItem.childItems)
if __name__ == '__main__':
app = QtGui.QApplication(sys.argv)
model = TreeModel()
view = QtGui.QTreeView()
view.setModel(model)
view.setWindowTitle("Simple Tree Model")
view.show()
sys.exit(app.exec_())
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