A different approach to avoiding accidently scroll changes #4274
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src/gui/qgsscrollarea.cpp
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Better use file templates in QtCreator ;)
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Please don't let the general crappiness of the coding in this PR distract from the bigger question. I deleted the PR guideline checklist for a reason ;)
src/gui/qgsscrollarea.h
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| begin : June 2016 | ||
| copyright : (C) 2016 by Nathan Woodrow | ||
| email : |
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@NathanW2 they will also find your email, even if you don't add it here!
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I just experimented with this for another use. All children that are registered are either "QObject" or "QWidget" but no futher subclasses. Maybe something related to only the superclass constructors being run but not the subclasses one? |
I think that's expected - according to the qt docs: "In both cases you can only rely on the child being a QObject (or, if QObject::isWidgetType() returns true, a QWidget). This is because in the QEvent::ChildAdded case the child is not yet fully constructed; in the QEvent::ChildRemoved case it might have already been destructed." But that would only be an issue if somewhere in the child constructors the event filter list is cleared. That doesn't seem likely to me. I think I know what the issue is - I think that in some cases when a widget is being added to the scroll area, it already has children added. In this case the recursive filter install isn't added for all the existing children. Should be an easy fix if this is the case - I'm testing now. |
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All fixed up now - a nice and clean approach which should be good merge. |
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great, can you make a custom widget for it? |
This adds a new QgsScrollArea widget which is a subclass of QScrollArea. QgsScrollArea has extra logic which temporarily blocks wheel events from hitting child widgets for a short period following a scroll of the area. This means that when scrolling a scroll area using the mouse wheel, values won't be accidentally changed if the mouse cursor momentarily lands on top of a widget. QScrollArea should no longer be used in any QGIS code or plugins, instead use QgsScrollArea to benefit from this fix.
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Done! |
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thanks a lot |
Here's a different approach to swallowing up scroll events to prevent accidental widget changes. This one sets a time out, so that any wheel events which occur up to 1 sec after a scroll wont change a child widget's value. This still allows the handy hover-and-scroll-wheel-to-change-value shortcut, just not directly after a scroll has occurred. Fixes the issue for me...