Any PyQt developers here?

[DFS]

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

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.