On Thu, Sep 24, 2015 at 10:58 AM, john lunzer <[email protected]> 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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