QGridLayout itemAtPosition with multiple items in a cell

swurl

Per a suggestion I found on another forum, I implemented grid lines with a custom QWidget with a paintEvent that draws the grid lines for me based on its max rows/cols. I then added it as such:

m_layout->addWidget(m_gridLine, 0, 0, -1, -1);

This works great, and grid lines are displayed perfectly. However, my application also depends upon the use of the itemAtPosition function within QGridLayout, in my case used to see if a widget is already occupying a space when the user tries to add it there:

for (int i = 0; i < data.rowSpan; ++i) {
    for (int j = 0; j < data.colSpan; ++j) {
        int row = data.row + i;
        int col = data.col + j;
        QLayoutItem *item = m_layout->itemAtPosition(row, col);
        if (item && item->widget() != m_gridLine) return true;
    }
}

with data being a struct containing {row, col, rowSpan, colSpan}

The issue I'm facing, however, is that no matter what, itemAtPosition always returns the grid line widget. This is in spite of me calling lower() on the grid line widget after each widget is added (which is a user-expedited runtime process).

Thus, essentially what I'm looking for is a way to "prioritize" certain widgets and "deprioritize" others, so that QGridLayout::itemAtPosition will always return the item e.g. at the top.

Pl45m4

@swurl

What you could do to verify your input and to get what you expect later, is testing your "data" with:

m_layout->getItemPosition(dataIndex, int *row, int *column, int *rowSpan, int *columnSpan)

https://doc.qt.io/qt-6/qgridlayout.html#getItemPosition

Therefore you only have to know the layout index of your data item and then you might be able to receive the valid input.

This is in spite of me calling lower() on the grid line widget after each widget is added (which is a user-expedited runtime process).

I dont think this will change something, since all widgets are in the QGridLayout and they all have their own cell and index.

https://doc.qt.io/qt-6/qwidget.html#lower

swurl

@Pl45m4 Indeed, this worked.

Another issue: the grid lines seem to still somehow be inconsistent with the widgets depending on how they're placed. Is there any better way to implement basic gridlines?