Guidelines needed using PageHeader+ListView header

[Tim Peeters]

ListView supports showing a section headers (for example A, B, C... in an address book), see http://doc.qt.io/qt-5/qml-qtquick-listview.html#section-prop

These ListView sections header can be configured to stay visible at the top of the ListView when it is moved (sections.labelPositioning = ViewSection.CurrentLabelAtStart). We need guidelines how to combine this with a (moving) PageHeader.

For example, by default the sections header would hide between the PageHeader when the PageHeader is locked, but the PageHeader can also be configured to hide when scrolling down in the listview or show when scrolling up. In that case, the sections header would be hidden behind the page header when scrolling up, and visible when scrolling down.

So, I think that section headers should never be combined with an auto-hiding page header. Best is to recommend to use a fixed PageHeader only when there are section headers. This needs to be added to the UX guidelines.

[Tim Peeters (tpeeters)]

Note that if there is a common pattern that requires PageHeader to be combined with ListView header, we'll probably need an ubuntu-ui-toolkit bug for that. But please decide on the UX first.