inserting custom Widget to listview

[Amit_3117]

Hi All,

I want to add one custom widget having a label and a button to my listview as one list item ...

If there is any code snippet or example code in this scenario .. please do suggest ..


Thanks,
Amit

[axeljaeger]

Use void QAbstractItemView::setIndexWidget ( const QModelIndex & index, QWidget * widget )
See also the warning in the documentation that you have to create a delegate if you want anything sensible with the widget. Generally, adding widgets to an itemview is a bad idea because it does not scale. If you 1000 rows, you need 1000 widgets in a naive implementation. The better implementation is to have only as much widgets as currently visibie and reuse widgets that get out of view for the appearing rows during scrolling. Basically, that is what the delegate does.

[faldzip]

If you want to show only standard controls like labels, buttons, check boxes then the most efficient way is to make your own item delegate where in paint() method you paint those controls with QStyle (see drawControl() and others). But those controls are only drawn so you have to implement by hand event processing in QAbstractItemDelegate::editorEvent() and you have to make eventFilter and install it on view's viewport to which you have to enable mouse tracking (and maybe set WA_Hover attribute to get Leave and Enter events - I don't remember exactly). Sounds complicate but it is the most efficient way in case with simple widgets, because you don't really have any real widget objects.

[MarkoSan]

Use void QAbstractItemView::setIndexWidget ( const QModelIndex & index, QWidget * widget )
See also the warning in the documentation that you have to create a delegate if you want anything sensible with the widget. Generally, adding widgets to an itemview is a bad idea because it does not scale. If you 1000 rows, you need 1000 widgets in a naive implementation. The better implementation is to have only as much widgets as currently visibie and reuse widgets that get out of view for the appearing rows during scrolling. Basically, that is what the delegate does.

So, then the custom widget is "placed" into delegate and delegate then handles number of showing widgets?

[axeljaeger]

I guess the widget replaces the delegate for that certain cell. If you have 100 rows, you will have to set 100 widgets. I think you will also have to to data binding of that widget yourself.

[MarkoSan]

I guess the widget replaces the delegate for that certain cell. If you have 100 rows, you will have to set 100 widgets. I think you will also have to to data binding of that widget yourself.

Hmm, I am a little confused right now. Here is how I want for cell to look like in attachment. Is delegate only interaction part (3 buttons on the right side) or whole cell with labels and pic?

[axeljaeger]

Delegate is responsible for drawing the whole cell's content including labels. It is also responsible for the behaviour.

[MarkoSan]

So, I subclass QWidget with all labels, pic, buttons, ..., layout them as in attachment and then I set this widget to subclassed QAbstractItemDelegate?

[axeljaeger]

Yes but there is one showstopper: The delegate will use the widget only in edit state. For all other cells, it will use QAbstractItemDelegate:aint.

[MarkoSan]

Yes but there is one showstopper: The delegate will use the widget only in edit state. For all other cells, it will use QAbstractItemDelegate:aint.

With "edit state" you mean Qt::EditRole?

[axeljaeger]

No: For example, if you have a table, you see a lot of cells, but only one cell can show a blinking textcursor at the same time. This cell is in "editing" state. All others are just "labels". You usually not use full widgets for the cells that are not in editing state because of performance reasons.

[MarkoSan]

Well, thanks, but that means my cell design will be performance demanding??