ubuntu-phone team mailing list archive

[Andrea Bernabei <andrea.bernabei@xxxxxxxxxxxxx>]

On Mon, Apr 18, 2016 at 11:57 AM, Omer Akram <omer.akram@xxxxxxxxxxxxx>
wrote:

> Hi!
>
> While working on a pet project[1] for the Phone, an issue that I faced was
> stuttering scrolling in listviews. QML tips page[2] suggested to use
> Flickable+Column+Repeater combination to have smooth scrolling, that worked
> and is currently what I have implemented in my app but I always thought
> that was not the perfect solution.
>
> With some knowledge of how Android ListView works and its mechanism of
> recycling ListView items, I wrote a hack[3] to achieve something similar in
> QML.
>
> What I am doing is:
>
>    - Create elements visible on screen at single instance + 2
>    - Set contentHeight to number of elements*each element height
>    - On flick upwards, when an element goes offscreen, set its Y property
>    to the bottom of the list.
>    - Not handled the down flick case just yet.
>
> So with only a few elements created, we can reuse same elements but with
> different data. I am not sure if there already exists some standard
> component for that or not. If not, then this idea is open for discussions
> and I would like to contribute it as a standard component once we figure
> out all the details and agree on them.
>
> Thanks!
>
>
Hi Omer,

I've got some early feedback :) I haven't had a proper look at the code yet
but, if I understood it correctly, the idea is repositioning Items which
are inside a Column.
Isn't that against what Column is for?

Cheers,
Andrea


>
> [1] https://launchpad.net/ubuntu-soundcloud-app
> [2]
> https://wiki.qt.io/Performance_tip_QML_other#Fixed_length_lists_with_Flickable.2BColumn.2BRepeater
> [3]
> http://bazaar.launchpad.net/~om26er/+junk/recycle_list_view/view/head:/RecycleListView/Main.qml
>
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