Calendar with QTableWidget and QItemDelegate

[d_stranz]

And a second question:
What is better for performance: handling the whole table design (background color, text etc.) directly via QItemDelegate:aint(...) or would it be better to create QTableWidgetItems and set the specific background colors? I mean, setting background colors via delegate would result in updating the background color each time anything happens, but that is not neccessary for me, because I set the background colors once and they are static. On the other hand, I could imagine that the delegate will do that anyway, because, as I know now, it gets the information from the table so it will repaint the backgrounds like the QTableWidgetItems orders it...

So, is there any sense in using QTableWidgetItems when I use a custom delegate anyway?

It sounds to me that what you really need is to pop up a level in the widget hierarchy and use a QTableView (instead of QTableWidget) and derive a model from QAbstractTableModel. In the model's data() method, you have control over all kinds of appearance things. See Qt::ItemDataRole. In trying to implement a delegate that jumps through all these hoops, you are essentially reinventing all of the functionality that QAbstractTableModel / QTableView give you for free.

[anda_skoa]

n my case, I let all data draw directly via QPainter, so the data is never stored into the table. One could say, the table doesn't know, that any data exists.

You are saying that your delegate uses the row and column information to get the data from a separate data structure?

How can I address this data and how can I react on user interaction with this data? I mean, I'd like to have clickable links drawn with QPainter::drawText(..), but I don't know where to ask for information when the whole view doesn't know anything about the data... How can I do that?

Well, if you get your data from some custom data structure, then why can you access it in paint() but not when handling user event?

What is better for performance: handling the whole table design (background color, text etc.) directly via QItemDelegate:aint(...) or would it be better to create QTableWidgetItems and set the specific background colors? I mean, setting background colors via delegate would result in updating the background color each time anything happens, but that is not neccessary for me, because I set the background colors once and they are static. On the other hand, I could imagine that the delegate will do that anyway, because, as I know now, it gets the information from the table so it will repaint the backgrounds like the QTableWidgetItems orders it...

Well, the painting is always done by the delegate.
Whether you use the background brush provided by via the options or decide on color based on some data in the delegate shouldn't make much difference.

So, is there any sense in using QTableWidgetItems when I use a custom delegate anyway?

As I said before, those handle different levels.
The widget item is used as an API for adding data to the table.
The delegate is painting that data.

Whether you want to handle the data via widget items or via a model is orthogonal to using a delegate to achieve a custom visualization.

Cheers,
_