Regarding Signals and Slots

[JoeCFD]

void QTableWidget::cellChanged(int row, int column)

This signal is emitted whenever the data of the item in the cell specified by row and column has changed.

[Shruthi]

@JoeCFD Thank you. I will try this.

[Shruthi]

@mrjj yes correct.

[mrjj]

@Shruthi

Ok. o.O

void MainWindow::on_tableWidget_itemChanged(QTableWidgetItem *item)
{
    int numCols = ui->tableWidget->columnCount();
    int numRows = ui->tableWidget->rowCount();
    auto newValue = item->text();
    for (int row = 0; row < numRows; ++row) {
        for (int col = 0; col < numCols ; ++col) {
            auto cellItem = ui->tableWidget->item(row, col);
            if (cellItem) cellItem->setText(newValue);
        }
    }
}

[Shruthi]

@mrjj Thank you so much. I will try this.

[mrjj]

@Shruthi
Np. Even its a bit odd :)

make sure you use the itemChanged signal so it first happens when user press
enter.

[Shruthi]

@mrjj Sure I will be using itemChanged signal only. Thanks again :)

[Shruthi]

@mrjj I am using the same section of code which you have mentioned above, It is working. But before user changes the value in the tablewidget, it is filling with some garbage value. Please let me know,what is the issue? Our changes is interfering with the insertion step itself. How to avoid this?

[mrjj]

@Shruthi
HI
I think the signal will also trigger when you fill the table.

To avoid that.
Either fill the table BEFORE you connect the signal.

or block its signals while filling it
https://doc.qt.io/qt-5/qsignalblocker.html

[Shruthi]

@mrjj sure I will refer the link. Thank you.

[Shruthi]

This post is deleted!

[JonB]

@Shruthi
Your calls to blockSignals(false); and >blockSignals(true) are the wrong way round. You are supposed to block the signals for the duration of your changes. You also don't want to leave signals blocked when your slot exits!

[Shruthi]

This post is deleted!

[mrjj]

Hi
if the goal is to block signals then as jonB says you must do

ui->tableWidget->blockSignals(true);
xxxxx
ui->tableWidget->blockSignals(false);

not reverse

[JonB]

@Shruthi
As @mrjj has just said. All you were supposed to do was swap one false with one true.

[Shruthi]

@JonB @mrjj Ya I tried swapping, but it's still the same.

[Shruthi]

Can we achieve this without using blocksignals? If so, what changes needs to be done? @JonB @mrjj

[JonB]

@Shruthi
So your slot is firing while you are initialising. You have a couple of choices:

• Here you also want to block signals during fillTableWidget(), so add that; or

• Do not connect() the slot till after fillTableWidget() has done its work. If you are using Designer's autoconnect of slots change over to your own connects.

[Christian Ehrlicher]

Just one question - what should fillTableWidget() do at all (apart from the fact that it does not compile at all)? When rowCount() is greater than 0 then empty QTableWidgetItem's are set, nothing more.

Please provide a minimal, compilable example to reproduce your issue!

[Shruthi]

This post is deleted!