Any PyQt developers here?

[DFS]

Having problems with removeRow() on a QTableView object.

After calling removeRow(), the screen isn't updating. It's as if the
model is read-only, but it's a QSqlTableModel() model, which is not
read-only.

The underlying SQL is straightforward (one table) and all columns are
editable.

None of the editStrategies are working either.

I tried everything I can think of, including changes to the
EditTriggers, but no luck. HELP!

FWIW, the same removeRow() code works fine with a QTableWidget.

-------------------------------------------------------------------
object creation and data loading all works fine
-------------------------------------------------------------------
#open db connection
qdb = QSqlDatabase.addDatabase("QSQLITE")
qdb.setDatabaseName(dbname)
qdb.open()

#prepare query and execute to return data
query = QSqlQuery()
query.prepare(cSQL)
query.exec_()

#set model type and query
model = QSqlTableModel()
model.setQuery(query)

#assign model to QTableView object
view = frm.tblPostsView
view.setModel(model)

#get all data
while(model.canFetchMore()): model.fetchMore()
datarows = model.rowCount()



-------------------------------------------------------------------
iterate selected rows also works fine
SelectionMode is Extended.
identical code works for a QTableWidget
-------------------------------------------------------------------
selected = tbl.selectionModel().selectedRows()
#reverse sort the selected items to delete from bottom up
selected = sorted(selected,reverse=True)
for i,val in enumerate(selected):
tbl.model().removeRow(selected[i].row())

[Thomas Passin]

On 10/25/2022 1:03 PM, DFS wrote:
> Having problems with removeRow() on a QTableView object.

removeRow() isn't listed as being a method of a QTableView, not even an
inherited method, so how are you calling removeRow() on it? (See
https://doc.qt.io/qt-6/qtableview-members.html)

[Barry Scott]

There is an active PyQt mailing list that has lots of helpful and knowledgeable people on it.

https://www.riverbankcomputing.com/mailman/listinfo/pyqt

Barry

> --
> https://mail.python.org/mailman/listinfo/python-list
>

[DFS]

On 10/25/2022 1:45 PM, Thomas Passin wrote:
> On 10/25/2022 1:03 PM, DFS wrote:
>> Having problems with removeRow() on a QTableView object.
>
> removeRow() isn't listed as being a method of a QTableView, not even an
> inherited method, so how are you calling removeRow() on it? (See
> https://doc.qt.io/qt-6/qtableview-members.html)

* I thought I was calling it the same way it's called with
QTableWidgets: tbl.removeRow()

But looking at my code again I was using tbl.model().removeRow()


* Plus I found several others online with similar removeRow() issues
with QTableViews.


* Plus the code didn't throw an error:

selected = tbl.selectionModel().selectedRows()
#reverse sort the selected items to delete from bottom up
selected = sorted(selected,reverse=True)
for i,val in enumerate(selected):
tbl.model().removeRow(selected[i].row())

But... as you say, when looking at the docs, removeRow() isn't even one
of the slots for QTableViews. So duh!

I see the QTableView.hideRow(row) method, which does exactly what I need.

Thanks man!

[DFS]

On 10/25/2022 2:03 PM, Barry Scott wrote:
> There is an active PyQt mailing list that has lots of helpful and knowledgeable people on it.
>
> https://www.riverbankcomputing.com/mailman/listinfo/pyqt
>
> Barry

Thanks. I'll send some questions their way, I'm sure.

[DFS]

On 10/25/2022 1:45 PM, Thomas Passin wrote:

> On 10/25/2022 1:03 PM, DFS wrote:
>> Having problems with removeRow() on a QTableView object.
>
> removeRow() isn't listed as being a method of a QTableView, not even an
> inherited method, so how are you calling removeRow() on it? (See
> https://doc.qt.io/qt-6/qtableview-members.html)

Since you helped me on the last one, maybe you could try to answer a
couple more [probably simple] roadblocks I'm hitting.


I just wanna set the font to bold/not-bold when clicking on a row in
QTableView.



With a QTableWidget I do it like this:

font = QFont()
font.setBold(True) or False
QTableWidget.item(row,col).setFont(font)



But the QTableView has data/view 'models' attached to it and that syntax
doesn't work:


Tried:
font = QFont()
font.setBold(True) or False
model = QTableView.model()
model.setFont(model.index(row,col), font)

Throws AttributeError: 'QSqlTableModel' object has no attribute 'setFont'


This doesn't throw an error, but doesn't show bold:
model.setData(model.index(tblRow, col), font, Qt.FontRole)


Any ideas?

Thanks

[Thomas Passin]

You definitely need to be setting the font in an item. I'm not sure but
I think that your QFont() doesn't have any properties, so it doesn't do
anything. I found this bit in a page - it's in C++ instead of Python
but that doesn't really make a difference except for the exact syntax to
use -


https://forum.qt.io/topic/70016/qlistview-item-font-stylesheet-not-working/4

QVariant v = ModelBaseClass::data(index,role);
if( condition && role == Qt::FontRole )
{
QFont font = v.value<QFont>();
font.setBold( true );
v = QVariant::fromValue<QFont>( font );
}

IOW, you have to get the font from the item, then set it to bold, which
you would do with setFont(). Then you set that new font on the item. Of
course you would have to unset bold on it later. See

https://doc.qt.io/qt-6/qtablewidgetitem.html#font

Instead of "item", you might need to operate on "row". I didn't look
into that. Since a row probably doesn't have just one font (since it
can have more than one item), you'd still have to get the font from some
item in the row.

You might also be able to make the item bold using CSS, but I'm not sure.

> Thanks

Internet searches are your friend for questions like this. I've never
worked with a QTableView, so I had to start with some knowledge about
some other parts of QT. I found the first page searching for "qt set
qtableview row font", and the second searching for "qtablewidgetitem".

[Thomas Passin]

This looks like a useful tutorial -

https://doc.qt.io/qt-6/modelview.html

On 10/27/2022 3:47 PM, Thomas Passin wrote:
> On 10/27/2022 11:15 AM, DFS wrote:

[Thomas Passin]

On 10/28/2022 1:01 AM, Thomas Passin wrote:
{snip]

>> You might also be able to make the item bold using CSS, but I'm not sure.

Apparently so:

QTreeView::item:selected {
background-color: #1d3dec;
color: white;
}

See https://joekuan.wordpress.com/2015/10/02/styling-qt-qtreeview-with-css/.

[DFS]

Before I posted I spent a couple hours looking online, reading the docs,
and trying different ways.

I found one person that said they did it but their syntax didn't work.
But it doesn't throw an error either.

model.setData(model.index(tblRow, col), font, Qt.FontRole)

When I'm done with my app (nearly 2K LOC) I'm going to put a summary out
there somewhere with a bunch of examples of easy ways to do things. For
one thing I wrote zero classes. Not one.

> I've never
> worked with a QTableView, so I had to start with some knowledge about
> some other parts of QT.  I found the first page searching for "qt set
> qtableview row font", and the second searching for "qtablewidgetitem".

I used TableWidgets in 2 apps and no problems. In this app there's more
data and more sorting, and one of the TableWidgets took a while to load
35K rows (7 items per row). So I tried a TableView. Incredibly fast -
4x the speed - but it doesn't have the bolding in place yet. That could
slow it down.

As you know, a TableView is tied to the underlying datasource (in my
case via a QSqlTableModel), but it's much faster to show data than a
TableWidget, because with the widget you have populate each cell with
setItem().

The Widget is slower but easier to work with. So it's a tradeoff.


And I think I found some bugs in the TableViews. The Views have
editStrategies() that control how data is updated (if the model supports
editing), but they don't work the way the docs say they do.

In my app, when I click on a row a flag field is changed from N to Y
onscreen (well, it's hidden but it's in the row).

model.setData(model.index(row,7), 'Y')


OnFieldChange : all changes to the model will be applied immediately to
the database.
model.setEditStrategy(QSqlTableModel.OnFieldChange)

Doesn't work right. The screen is updated the first row you click on,
but the db isn't updated until you reload the view.


OnRowChange : changes to a row will be applied when the user selects
a different row.
model.setEditStrategy(QSqlTableModel.OnRowChange)

Doesn't work right. The screen is updated the first row you click on,
but the db isn't updated until you reload the view.


OnManualSubmit : all changes will be cached in the model until either
submitAll() or revertAll() is called.
model.setEditStrategy(QSqlTableModel.OnManualSubmit)

This works the best: the screen changes on each row I click, but the db
isn't updated even if I do submitAll() right after setData(). Have to
reload the view for the changes to propagate to the db.

Since none work as they say, the issue is probably on my end. Don't know.

I just ended up issuing a quick SQL UPDATE statement for the row.


If you really want speed use the read-only QSqlQueryModel(). Loads 35K
rows to screen in 1/2 a second (but no bolding applied - I really have
to figure that out, as it's a central feature of the GUI)


Thanks for your help.

[Michael Torrie]

On 10/28/22 21:31, DFS wrote:
> I found one person that said they did it but their syntax didn't work.
> But it doesn't throw an error either.
>
> model.setData(model.index(tblRow, col), font, Qt.FontRole)

I wouldn't expect that to work but it's understandable why it didn't
throw an error. setData() is used to edit the contents of the model at
the provided index. Remember a model can store anything. All this does
is replace whatever was at that index with a Font object instance. I'm
puzzled why you keep trying to mess with the model when it's the view
that does the actual font setting. Remember that a single model can be
used with more than one view at the same time, each view implementing
its own style. Thus a model has no information like fonts in it, nor
should it, other than perhaps HTML text markup that the view will render.

Did you consult the folk on the PyQt mailing list? Or even the main Qt
lists? This isn't language-specific stuff you're asking about.