[Interest] item edit on mouse over - was: dynamic widget creation in QScrollArea

Frank Rueter | OHUfx frank at ohufx.com
Fri Aug 12 04:12:27 CEST 2016


So I made some progress here:
I am now using the QListView's mouseMoveEvent() to get the item under 
the mouse and edit() it:

     def mouseMoveEvent(self, event):

         '''Find item under mouse and pop it into edit mode'''
         index = self.indexAt(event.pos())
         if index.isValid():
             self.edit(index)
         super(ElementView, self).mouseMoveEvent(event)

In my Delegate's createEditor() method I have this:

     def createEditor(self, parent, option, index):
         proxyModel = index.model()
         item = 
proxyModel.sourceModel().itemFromIndex(proxyModel.mapToSource(index))
         currentEditor = *MyMovie*(item, parent=parent)
         currentEditor.*mouseLeftWidget*.connect(self.emitCloseEditorSignal)
         return currentEditor

The *MyMovie() *class has a leaveEvent that emits the *mouseLeftWidget* 
signal.


The above works and the various instances of MyMovie() play back on 
mouse over inside my QWLIstView and stop when the mouse leaves them, but 
for some reason I still get "edit: editing failed" messages when I move 
the mouse around quickly.
I don't get those messages when I move the mouse slowly though, which is 
interesting.

Does anybody have an idea why that would be?

Cheers,
frank



On 9/08/16 5:50 PM, Frank Rueter | OHUfx wrote:
> And one more follow up:
> I just tried this in my view class:
>     def mouseMoveEvent(self, event):
>         '''Find item under mouse and pop it into edit mode'''
>         index = self.indexAt(event.pos())
>         self.edit(index)
>
> This successfully pops the first item under the mouse into edit mode, 
> but as I keep moving the cursor around I just get:
>     edit: editing failed
>
> This one stumped me yesterday as well when I tried to use the 
> Delegate's paint method to trigger it's editor on mouse over.
>
> Does anybody have any ideas how to start editing on mouse over with 
> delegates and list views?
>
> Cheers,
> frank
>
>
>
> On 9/08/16 5:27 pm, Frank Rueter | OHUfx wrote:
>> Ok, so after some more experimenting I am fairly certain that using 
>> seItemWidget inside the delegate's paint event is a bad idea.
>> My second approach seems more promising so far: Using the custom 
>> movie player widget as the delegate's editor, even though I don't 
>> actually want to edit anything.
>> However, since I need the movie player to start playing on mouse 
>> over, I need to work out how to pop the item under the mouse into 
>> edit() mode (and finish editing when the mouse leaves the item).
>> After googling a bit it seems a few others have tried this but to no 
>> avail.
>>
>> Any ideas on that one?
>>
>> Cheers,
>> frank
>>
>> On 8/08/16 4:28 pm, Frank Rueter | OHUfx wrote:
>>> Hi Bo,
>>>
>>> I have followed your advise and gone back to QListView with a delegate.
>>> My first test was to render the custom widget I need via the 
>>> delegate paint method. This populates a static version of the movie 
>>> player (the custom widget I need).
>>> Then, also in the delegate's paint method, I use setItemWidget if 
>>> the mouse hovers over the item, to get the fully fledged and 
>>> interactive widget.
>>> This seems to be promising but it kinda feels wrong to set an item 
>>> widget in the paint method. Should I worry?
>>>
>>> Also, I can't get the rendered image to line up with the item widget 
>>> itself. The render seems to have the correct size but the widget, 
>>> when the mouse hovers over the item, is slightly off, causing the 
>>> item to pop a little and leave out-of-date paint artifacts when the 
>>> mouse leaves again.
>>>
>>> Below is my test code for the delegate.
>>>
>>> Now I am wondering if the below approach is acceptable (setting an 
>>> item widget inside the delegate's paint event).
>>> Alternatively I'm wondering if I could/should use the delegate's 
>>> createEditor method to display the widgets of all visible items to 
>>> achieve the same thing (which is full interactive and animated 
>>> widget in all visible items). I have, however, not been able to 
>>> figure out how to call the editor on mouse enter, which I need 
>>> because the movie is supposed to play when the mouse hovers over it.
>>>
>>> Any opinions on this?
>>>
>>> Cheers,
>>> frank
>>>
>>>
>>> class DelegateOld(QtGui.QItemDelegate):
>>>
>>>     def __init__(self, parent = None):
>>>
>>>         super(Delegate, self).__init__(parent)
>>>         self.thumbnail = None
>>>
>>>     def paint(self, painter, option, index):
>>>         item = index.model().itemFromIndex(index)
>>>         self.thumbnail = MyMovie(item)
>>>
>>>         if option.state & QtGui.QStyle.State_MouseOver:
>>>             # swap render for actual widget here. So the user can 
>>> interact with it - doesn't feel right though to do this in the paint 
>>> event
>>>             existingThumb = self.view.indexWidget(index)
>>>             if not existingThumb:
>>>                 self.view.setIndexWidget(index, self.thumbnail)
>>>         else:
>>>             self.thumbnail.render(painter, 
>>> QtCore.QPoint(option.rect.x(), option.rect.y()))
>>>
>>>     def sizeHint(self, option, index):
>>>         return MyMovie.thumbSize
>>>
>>> On 4/08/16 8:36 pm, Bo Thorsen wrote:
>>>> Den 04-08-2016 kl. 10:05 skrev Frank Rueter | OHUfx:
>>>>> I am playing with the idea of writing a custom widget based on
>>>>> QScrollArea, where widgets are created as the user scrolls.
>>>>> I'm just hoping to bounce the general idea of you guys here to see if
>>>>> I'm heading in the right direction:
>>>>>
>>>>> I have a heap of custom widgets, potentially thousands, depending 
>>>>> on the
>>>>> contents of a database.
>>>>> I'd like to show them in a grid that fits as many widgets 
>>>>> horizontally
>>>>> as will fit in the current window size (dynamic).
>>>>> I would also like smooth vertical scrolling.
>>>>>
>>>>> If I create a single parent widget with a grid layout that creates 
>>>>> all
>>>>> widgets on start up, it takes ages.
>>>>> So I'm thinking if I use the child widgets' visibleRegion() to 
>>>>> find the
>>>>> ones currently visible in the scroll area, then figure out the 
>>>>> indexes
>>>>> of the widgets in the rows above and below to create them 
>>>>> dynamically,
>>>>> that should speed up the startup and still provide smooth scrolling.
>>>>>
>>>>> Obviously I'd have to manually scale the scroll area based on the
>>>>> maximum amount of widgets and the parent widget's width to get an
>>>>> indicative scrollbar.
>>>>> Not sure how tricky that will be.
>>>>>
>>>>> Does that sound crazy or doable?
>>>>>
>>>>> Basically I am trying to re-create the behavior of a QListView in 
>>>>> icon
>>>>> mode. I tried using QListView with delegates, but couldn't get the
>>>>> delegates to provide the kind of complexity I need for the child 
>>>>> widgets
>>>>> which I have already written (which are basically mini movie players
>>>>> that can be drag&dropped and have playback all at once on demand).
>>>>>
>>>>> Any thoughts on this before I dive into this little experiment?
>>>>
>>>> I don't think that sounds unreasonable. If I were you, I would try 
>>>> very hard to stay with QListView instead, but other than that it 
>>>> doesn't sound hard to do. Time consuming, yes, but not difficult.
>>>>
>>>> Bo Thorsen,
>>>> Director, Viking Software.
>>>>
>>>
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