As usual this process is solid. I made it about halfway through this
process before getting lost. I will remember to reference this in the
future. Hopefully will get time to make the change soon.
On Friday, September 25, 2015 at 8:01:05 AM UTC-4, Edward K. Ream wrote:
>
> On Thu, Sep 24, 2015 at 10:58 AM, john lunzer <lun...@gmail.com
> <javascript:>> wrote:
>
> I'm finding myself stumped by the KeyHandler class. One thing that the
>> autocomplete Qt popup doesn't handle right now is PgUp and PgDown, both of
>> these keybinding exit the popup. I was trying to fix this but I'm having
>> difficulty figuring out where to do this.
>>
>> Any guidance would be much appreciated.
>>
>
> No doubt about it, key handling is complex. I never remember the
> details.
>
> Here is how I found the interesting code. I recommend variations of this
> technique to find relevant code.
>
> 1. I started with the gui *independent* code in leoPy.leo#Code-->Gui base
> classes-->@file leoKeys.py-->class AutoCompleterClass
>
> 2. I knew there was an ivar that tells whether to use inline completion or
> a Qt popup. I found the use_qcompleter ivar in the ctor. Searching for
> usages of that ivar, I eventually found ac.show_completion_list, which has
> this code:
>
> if self.use_qcompleter:
> # Put the completions in the QListView.
> if self.qw:
> self.qw.show_completions(tabList)
>
> 3. The qw ivar is the Qt-related widget, so I searched for "def
> show_completions". I found this class:
>
> leoPy.leo#re: qt completer-->class LeoQListWidget(QListWidget)
>
> Now we're getting somewhere :-)
>
> BTW, I could have found this class another way. I knew that this
> Qt-related class existed somewhere in this tree: leoPy.leo#Code-->Qt gui,
> but I had forgotten which file. So an alternate way of finding this class
> would have been to look for all the classes in the Qt-related tree, that is
> leoPy.leo#Code-->Qt gui
>
> Anyway, the relevant method of the LeoQListWidget class is:
>
> def keyPressEvent(self, event):
> '''Handle a key event from QListWidget.'''
> trace = False and not g.unitTesting
> c = self.leo_c
> w = c.frame.body.wrapper
> qt = QtCore.Qt
> key = event.key()
> if event.modifiers() != qt.NoModifier and not event.text():
> # A modifier key on it's own.
> pass
> elif key in (qt.Key_Up, qt.Key_Down):
> QtWidgets.QListWidget.keyPressEvent(self, event)
> elif key == qt.Key_Tab:
> if trace: g.trace('<tab>')
> self.tab_callback()
> elif key in (qt.Key_Enter, qt.Key_Return):
> if trace: g.trace('<return>')
> self.select_callback()
> else:
> # Pass all other keys to the autocompleter
> # via the event filter.
> w.ev_filter.eventFilter(obj=self, event=event)
>
> So this is where the change should be made. *Important*: the default
> eventFilter method, that is, LeoQtEventFilter.eventFilter, is insanely
> complicated. Don't change it! So you have to special case PageUp and
> PageDown in lqlw.keyPressEvent.
>
> To repeat, I *never *try to remember implementation details. I had
> forgotten that LeoQListWidget.keyPressEvent event existed. The only things
> I knew at the start was:
>
> 1. The gui-independent autocompleter in @file leoKeys.py-->class
> AutoCompleterClass
> has one or more ivars that would tell when to use Qt popup completions
> rather than inline completions.
>
> 2. There was a Qt-specific class that handles Qt popup completions. This
> class is defined somewhere in the tree whose root is leoPy.leo#Code-->Qt
> gui.
>
> 3.
> Changing LeoQtEventFilter.eventFilter should be a last resort.
>
> HTH. Please feel free to ask more questions.
>
> Edward
>
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