QTableWidget issues

[Djony]

Thank you for the answer.
If I understood you right, you mean to make class which inherits qtablewidgetitem and implement a method of that class which colors the cell in adequate manner? But, the question is, how can I control the size of areas in one cell (if you look at the picture, you will notice that there are 3 areas in one cell: green, red, blue parts). The height is the height of cells, but width? Thanx for any replies!

[wysota]

If I understood you right, you mean to make class which inherits qtablewidgetitem and implement a method of that class which colors the cell in adequate manner?

No, I meant to subclass QItemDelegate or QAbstractItemDelegate and reimplement painting and/or drawBackground routines.

But, the question is, how can I control the size of areas in one cell (if you look at the picture, you will notice that there are 3 areas in one cell: green, red, blue parts). The height is the height of cells, but width?

You have to reimplement the delegate's paint or drawDisplay() methods and draw the rectangles yourself.

[Djony]

How can I get positions and dimensions of these rectangles? They are inside table cells.

[wysota]

You get the width of the whole cell rectangle. You can then calculate lengths of each of the bars knowing the percentage to be displayed.

[Djony]

Thanx for reply, but I don't get it completely. I am looking at some examples in Qt Assistant and I can't catch when are those methods from QItemDelegate's class child called. Where is in my case, drawDisplay() method called?

[wysota]

The delegate is used by the view to render items. So every time an item needs to be drawn, the delegate is called to do that. drawDisplay is called by paint() which in turn is called by the view.

[Djony]

The delegate is used by the view to render items. So every time an item needs to be drawn, the delegate is called to do that. drawDisplay is called by paint() which in turn is called by the view.

In my case, is that going to happen when I insert row in my table or when I set new QTableWidgetItem for my new cell? Should paint() be called in code, or "automatically"?

[wysota]

The delegate is called automatically whenever the view feels like repainting an item.

[Djony]

Thanx for replies and sorry for stupid questions . What methods I need to reimplement in order to get my QItemDelegate to paint only 6th colum? Secondly, the painting depends on data (3 integer variables), as you can see on picture. How can I send those integers to QItemDelegate so the delegate can paint cell properly? Is there another way?

[wysota]

What methods I need to reimplement in order to get my QItemDelegate to paint only 6th colum?

paint() and/or drawDisplay(), depending on which class you subclass. It also depends how you install the delegate. You can install it for a single column only or for all columns (then you have to reimplement paint() to call the base class implementation for columns other then 6th.

Secondly, the painting depends on data (3 integer variables), as you can see on picture. How can I send those integers to QItemDelegate so the delegate can paint cell properly? Is there another way?

There are different ways to do this. I'd suggest using different item roles for each "colour" or setting a list of values as the data for the display role (setData(6, Qt::DisplayRole, QList<int>() << 1 << 2 << 3)) and then retrieve each value from within the delegate.

And I think it would be easier for you to subclass QItemDelegate and reimplement its paint() method than to go for drawDisplay().

[Djony]

paint() and/or drawDisplay(), depending on which class you subclass. It also depends how you install the delegate. You can install it for a single column only or for all columns (then you have to reimplement paint() to call the base class implementation for columns other then 6th.

How can I install delegate for just single column? I have decided to use QItemDelegate and to reimplement it's paint metod.

There are different ways to do this. I'd suggest using different item roles for each "colour" or setting a list of values as the data for the display role (setData(6, Qt:isplayRole, QList<int>() << 1 << 2 << 3)) and then retrieve each value from within the delegate.

Maybe I've explained it wrong in previous post The data shown in that "colored column" will not be changed by the user. It should be shown and "colored" by the delegate based upon the values that some other class reads from SQLITE 3 database. If you mean't the same thing, which methods from QItemDelegate I need to reimplement and how (in which direction, I don't have any idea)? How can I "send" those integers to delegate so he can color cells?

[wysota]

How can I install delegate for just single column?

First thing to do is to browse QAbstractItemView docs and find the answer there.

If you mean't the same thing,

I did.

which methods from QItemDelegate I need to reimplement and how (in which direction, I don't have any idea)? How can I "send" those integers to delegate so he can color cells?

My previous answer still stands. Please read about item roles and Qt MVC implementation.