QTableWidget Operations over columns

[Abderaouf]

@mrjj
Thanks mrjj. I think I fixed that based on Chris-kawa previous comments. I have another issue. I want to creat a Qpushbutton that fill the items of the second table based on the data of the first table using an if condition that check the QString of the 2nd column. If the value is "Y", the calculation should be on one way and if the value is "N" the calculation are done in another way. The code is not showing any error but .exe is crashing when I push the button. below is my code, thanks for reviewing it and advising:

void CFAdvisor::on_Button4_clicked()
    {
    QString str1;
    QString str2 = "Y";
    QString str3 = "N";

      for (int row = 0; row < ui->m_ptable_ConvDesign->rowCount(); ++row)
      {
          QTableWidgetItem *stagepulse_item = ui->m_ptable_ConvDesign->item(row, 1);
          str1 = stagepulse_item->data(Qt::DisplayRole).toString();
      }

    for (int column = 0; column < ui->m_ptable_Conductor->columnCount(); ++column)
    {
      for (int row = 0; row < ui->m_ptable_Conductor->rowCount(); ++row)
      {
          if (str1 == str2)
           {

        QTableWidgetItem *PropConCond_item = ui->m_ptable_Conductor->item(row, 1);
        QTableWidgetItem *PropConConv_item = ui->m_ptable_ConvDesign->item(row,2);
        PropConCond_item->setData(Qt::DisplayRole,PropConConv_item->text().toDouble());

        QTableWidgetItem *SlurryVolCond_item = ui->m_ptable_Conductor->item(row, 4);
        QTableWidgetItem *SlurryVolConv_item = ui->m_ptable_ConvDesign->item(row,5);
        SlurryVolCond_item->setData(Qt::DisplayRole,qRound(((ui->Input_DesSLF-> text().toDouble())) * (SlurryVolConv_item->text().toDouble())));

        QTableWidgetItem *CleanVolCond_item = ui->m_ptable_Conductor->item(row, 2);
        CleanVolCond_item->setData(Qt::DisplayRole,qRound((SlurryVolCond_item->text().toDouble()) / ( 1 + ((ui->label_PropAVF1->text().toDouble()) * (PropConCond_item->text().toDouble())))));

           }

           if (str1 == str3)
           {

        QTableWidgetItem *PropConCond_item = ui->m_ptable_Conductor->item(row, 1);
        QTableWidgetItem *PropConConv_item = ui->m_ptable_ConvDesign->item(row,2);
        PropConCond_item->setData(Qt::DisplayRole,PropConConv_item->text().toDouble());

        QTableWidgetItem *SlurryVolCond_item = ui->m_ptable_Conductor->item(row, 4);
        QTableWidgetItem *SlurryVolConv_item = ui->m_ptable_ConvDesign->item(row,5);
        SlurryVolCond_item->setData(Qt::DisplayRole,SlurryVolConv_item->text().toDouble());

        QTableWidgetItem *CleanVolCond_item = ui->m_ptable_Conductor->item(row, 2);
        CleanVolCond_item->setData(Qt::DisplayRole,qRound((SlurryVolCond_item->text().toDouble()) / ( 1 + ((ui->label_PropAVF1->text().toDouble()) * (PropConCond_item->text().toDouble())))));

           }
        }
    }
}

Regards;

Raouf

[mrjj]

Hi
You should check all pointer to QTableWidgetItem * before using them.
It might return NULL and u crash.

Still if you place a break point and single step you should find the line that makes you crash.

[Abderaouf]

@mrjj I think it is that line, where I convert a QtableWidgetItem to QString:

str1 = stagepulse_item->data(Qt::DisplayRole).toString();

The syntax is right, I dont know what is the real reason though.

[mrjj]

@Abderaouf
It seems correct. You are getting a QVariant from data and call toString.
So when debugging it crash on this line?

[VRonin]

@Abderaouf said in QTableWidget Operations over columns:

I dont know what is the real reason though

probably stagepulse_item is a null pointer

also your logic does not work, at the moment the calculation is based on whether the last line, second column in m_ptable_ConvDesign is Y or N

[Abderaouf]

@mrjj When I run it, it works until I click on the button and then It crashes even though all the data are input. when I take out this line, the button doesn't work when I click at it.

[mrjj]

@Abderaouf
as @VRonin asks,
could stagepulse_item be NULL ?

[Abderaouf]

@VRonin how can I check if stagepulse_item is a null pointer??
I want to check the value of each line not only the last. I should probably add another for loop for the columns, right??

[mrjj]

@Abderaouf

if ( ! stagepulse_item) {
qDebug () << "NULL !!!";
return;
}

str1 = stagepulse_item->data(Qt::DisplayRole).toString();
...

• I want to check the value of each line not only the last. I should probably add another for loop for the columns, right??

yes something like that. currently u loop m_ptable_ConvDesign first and set str1 but that should be checked
while u loop over the rows. So for a row if COL have Y/N then do it accordingly.

[Abderaouf]

@mrjj

I used the below and it worked fine:

QTableWidgetItem *stagepulse_item = ui->m_ptable_ConvDesign->item(row, 1);
if(stagepulse_item!=NULL)
{
str1 = stagepulse_item->data(Qt::DisplayRole).toString();
}

Cheers;

[Abderaouf]

Gents;

One more challenge. I am trying to create a menu in my QTabWidget using the below basic code:

void CFAdvisor::CreateMenu()

{
fileMenu = MenuBar().addMenu(tr("&File"));
fileMenu->addAction(actionExit);
fileMenu-> addAction(actionPrint);
helpMenu = MenuBar() ->addMenu(tr("&Help"));
helpMenu-> addAction(actionContent);
helpMenu-> addAction(actionAbout);

}

I have a the error message though, it says the following:

C:\computing\Qt Designer\cfadvisor.cpp:488: error: 'menuBar' was not declared in this scope
fileMenu = menuBar()->addMenu(tr("&File"));
^

Any advise on how to correct this error. this is the Qt version I have.

Cheers

[mrjj]

Hi
Where is MenuBar() ?
if CFAdvisor is not a main window type then you need to create the MenuBar yourself if not already
added in Designer.

http://www.codeprogress.com/cpp/libraries/qt/QMenuBarAddMenu.php