Qt6: how to disable selection for empty cells in QTableView? - python-3.9

Question

I'm trying to display some data from a database in a grid view, similar to how a file manager works. I thought of using a QTableView as the grid view since it did what I wanted out of the box. However, as shown with the below given MRE, even if just a single cell has value, you can still select the other empty cells, how can I prevent this? Basically, I want to make it so that only cells with a value can be selected.
MRE:
from PySide6 import QtWidgets as qtw
from PySide6 import QtGui as qtg
from PySide6 import QtCore as qtc
ROW_COUNT = 5
COL_COUNT = 5
class Model(qtc.QAbstractTableModel):
def __init__(self, *args, **kwargs) -> None:
super().__init__(*args, **kwargs)
self._data = [[None for _ in range(COL_COUNT)] for _ in range(ROW_COUNT)]
def data(self, index: qtc.QModelIndex, role: qtc.Qt.ItemDataRole):
if not index.isValid():
return None
if role == qtc.Qt.ItemDataRole.DisplayRole:
return self._data[index.row()][index.column()]
return None
def setData(self, index: qtc.QModelIndex, value, role: qtc.Qt.ItemDataRole=qtc.Qt.ItemDataRole.DisplayRole):
if not index.isValid():
return False
if role == qtc.Qt.ItemDataRole.DisplayRole:
self._data[index.row()][index.column()] = value
return False
def rowCount(self, _):
return ROW_COUNT
def columnCount(self, _):
return COL_COUNT
app = qtw.QApplication()
view = qtw.QTableView()
view.setModel(Model())
view.setShowGrid(False)
view.verticalHeader().setVisible(False)
view.horizontalHeader().setVisible(False)
view.model().setData(view.model().createIndex(0, 0), "this is a test")
view.show()
app.exec()

Answer 1

You need to override the flags() and ensure that it doesn't return the ItemIsSelectable flag.
class Model(qtc.QAbstractTableModel):
# ...
def flags(self, index):
flags = super().flags(index)
if index.data() is None:
flags &= ~qtc.Qt.ItemIsSelectable
return flags
In your case, you also probably want to avoid the ItemIsEnabled, and since these two flags are the default one, you can just return NoItemFlags
def flags(self, index):
if index.data() is None:
return qtc.Qt.NoItemFlags
return super().flags(index)
If you also need to clear the selection, then you could subclass the view and do it in the mousePressEvent():
class TableView(qtw.QTableView):
def mousePressEvent(self, event):
index = self.indexAt(event.pos())
if index.isValid() and not index.flags() & qtc.Qt.ItemIsSelectable:
self.clearSelection()
else:
super().mousePressEvent(event)