How to get clicked item in QGridLayout?

ShinSat

Hi Gurus,

Does anybody tell me how to get clicked item(cell) in QGridLayout?

Thanks in advance for your help. :)
Regards,
Sat

Tirupathi Korla

@ShinSat
gridLayout.indexOf(QWidget_Clickded_item) will give index of clicked item..

Paul Colby

Just expanding on what @ShinSat said, with a contrived working example going from a mouse click to a grid layout item:

MainWindow::MainWindow(QWidget *parent, Qt::WindowFlags flags) : QMainWindow(parent, flags)
{
   QGridLayout * const grid = new QGridLayout();
   for (int row = 0; row < 5; ++row)
      for (int col = 0; col < 5; ++col)
          grid->addWidget(new QLabel(tr("%1:%2").arg(row).arg(col)), row, col);
    setCentralWidget(new QWidget);
    centralWidget()->setLayout(grid);
}

void MainWindow::mousePressEvent(QMouseEvent *event)
{
    QWidget * const widget = childAt(event->pos());
    qDebug() << "child widget" << widget;
    if (widget) {
        const QLabel * const label = qobject_cast<QLabel *>(widget);
        if (label) {
            qDebug() << "label" << label->text();
        }

        const int index = centralWidget()->layout()->indexOf(widget);
        qDebug() << "layout index" << index;
        if (index >=0) {
            const QLayoutItem * const item = centralWidget()->layout()->itemAt(index);
            qDebug() << "layout item" << item;
        }
    }
}

Cheers.

VRonin

If you need something like this I automatically suspect you are abusing QGridLayout and you really need a QTableView/QTableWidget or even a QGraphicsView or you should really reconsider your design

ShinSat

@VRonin said in How to get clicked item in QGridLayout?:

you really need a QTableView/QTableWidget or even a QGraphicsView

Well, I'm still considering the pros and cons between QGridLayout and TableView.
Can anybody share main difference(advantages/disadvantages) between them?

What I'm trying is exactly same as Ms-Excell where multiple tables linking together including sorting capability.
Some widgets such as QComboBox and QLineEdit are on the tables.

Regards,
Sat

VRonin

@ShinSat said in How to get clicked item in QGridLayout?:

What I'm trying is exactly same as Ms-Excell where multiple tables linking together including sorting capability.

The QTableView + Custom model is 100% the way to go. This is one of the rare cases I suggest a custom model from the start as Qt's models treat Qt::EditRole and Qt::DisplayRole (the formula and the value in Excel) as the same. You can probably get away with QStandardItemModel + a custom proxy that redirects Qt::EditRole to a user role though

ShinSat

@VRonin Thanks a lot for sharing informative thoughts. :)
Do you have any thoughts on performance between QGridLayout and QTableView?

I'm currently testing QGridLayout with 200 * 20 matrix and feeling initialization(creating widgets and adding it(addWidget) on the layout) is very slow. :<

Sat

VRonin

You are doing the equivalent of digging a ditch using a spoon. A spoon is great to eat soup but if you think of using it instead of a spade you are going to have a hard time

ShinSat

@VRonin said in How to get clicked item in QGridLayout?:

You are doing the equivalent of digging a ditch using a spoon.

Hahaha,,, you are right. :)
But I need to find a solution to that using Qt. (I'm using pyqt, though)

Sat

ShinSat

@ShinSat Designing well-formed integrated view from multiple data sets is the most challenging part of mine.
To simplify complex data into Qt-friendly data model is headache. :<
I think every data item will need to be saved together with its position(row, column). This looks too much but necessary, I guess.

Sat

ShinSat

Thank you very much for your help, all!
I gave up QGridLayout and now working with QTableView/QAbstractTableModel.
It's working well up to now. :)

Regards,
Sat