[PySide] QListView: drag&drop custom item

[Frank Rueter | OHUfx]

Thanks Jukka,

that's probably not a bad idea considering how much time I have spent 
trying to get this to work via QT.
I had been toying with the idea of just sending a dictionary of the 
relevant data, probably via a custom mime type, then re-creating the 
custom item upon drop in the receiving view.
I will keep that in mind as my last resort, but it feels like the 
default implementation of the drop behaviour is soooo close, that it 
should be possible to drop a custom item in some QT-ish way without 
re-invening the wheel - or is that too optimistic?

Here is a simple test code, hopefully we can get some more input with that:
http://pastebin.com/5UDPQFjh

With this code, when dropping an item fro the left into the right view, 
the print statement shows that a QStandardItem is produced rather than 
the custom item.

Any more takers?

Cheers,
frank

On 19/09/16 7:31 PM, Purma Jukka wrote:
> Hi,
> since you asked any ideas... In my app I have had to re-invent drag&drop for some items (because I want to drag QGraphicsItems in scene while having all kinds of effects on the items they are connected while keeping the main event loop running etc. ) and learned a habit to give up when I didn’t find Qt-way of doing things and instead to choose the simplest pythonesque way.
>
> So in your case at this point, I would have
> 1. 'start drag' store the dragged data, just the main payload, not the Q-item containing them, in some stable object (main window), just as ’main.dragged_object’.
> 2. when drag gets dropped to those problem recipients, in drop event, manually put the data from main window into recipient, without bothering with the Q-representations of the data.
>
> In my app I have a multipurpose controller-object and ctrl.dragged is used to store the non-qt data of whatever is being dragged. It was my solution to struggle with QStandardItems and such.
>
> In conclusion, since we are doing things with Python + Qt, I think we are justified to skip Qt when there is an easier (or more readable) pythonesque way of doing things.
>
> Jukka
>
>> Frank Rueter | OHUfx <frank at ohufx.com> kirjoitti 19.9.2016 kello 9.56:
>>
>> Anybody?
>> I'm still struggling with this. I went back to using a QStandardItem for a while which solved the dag&drop behaviour, but now I really need to use a custom item that inherits QStandardItem which breaks the drop behaviour again.
>>
>> Any ideas or guidance would be greatly appreciated.
>>
>> Cheers,
>> frank
>>
>>
>> On 16/08/16 7:26 PM, Frank Rueter | OHUfx wrote:
>>> Hi,
>>>
>>> I am trying to get drag&drop to work between two QListViews using a custom item.
>>> I can't find the info I need online other than this document which helped a little bit but now I'm stuck.
>>>
>>> Drag&drop from one QListView to another works fine when I use a QStandardItem to hold my data, but when I use a custom item I run into trouble, because the receiving model/view creates a QStandardItem when the incoming custom items are dropped.
>>>
>>> Ideally I could tell the receiving model to use my custom item as the default item and otherwise just do it's thing, but I suppose it won't be that easy?!
>>> I have played around with the receiving model's dropMimeData() and insertRows() methods but can't work out how to read the incoming data to then insert a custom item into the receiving model manually.
>>> In QAbstractItemModel.dropMimeData() I tried reading mimeData.data('application/x-qabstractitemmodeldatalist'), but that returns a byte stream that I don't know how to handle.
>>>
>>> Do I have to re-implement the sender's drag data as well to send the custom item in the first place?
>>>
>>> It seems that everything works out of the box except the creation of the QStandardItem upon drop, rather than my custom item, so I am hoping I don't have to re-invent the (drag&drop) wheel just to get that one part right?!
>>>
>>> Any advise would be greatly appreciated.
>>>
>>> Thanks,
>>> frank
>>>
>>>
>>>
>>> -- 
>>> <Sähköpostiliite.png>	vfx compositing | workflow customisation and consulting
>>>
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