Binding loop in MainView when using tabs in unity8 indicators

[Nick Dedekind]

When using a MainView and tabs in the unity8 indicators, there seems to be a binding loop causing a long delay at startup.

backgroundColour depends on Theme.palette.normal.background. [MainView.qml]
Theme [Ambiance/Suru] depends on the set backgroundColor. [MainViewStyle.qml]

Introduced by revision 621

[Nick Dedekind (nick-dedekind)]

For a demo:
https://code.launchpad.net/~nick-dedekind/+junk/unity8.tabs.MainView

[Timo Jyrinki (timo-jyrinki)]

Raising severity now that it seems to have bigger effect with Qt 5.2 (bug #1273958 + bug #1273956).

[Florian Boucault (fboucault)]

Adding the following snippet to any MainView triggers the bug:

    backgroundColor: "brown"

    Timer {
        running: true
        onTriggered: {
            gallery.backgroundColor = "white";
        }
    }

[Zsombor Egri (zsombi)]

The fix attached does not solve the binding loops we have when the theme is updated upon MainView's component completion. The binding loop appears only on themes which derive from Ambiance and do not override the MainViewStyle structure. To avoid such binding loops derived themes should completely redesign MainViewStyle and not use any code from the original style.

Apps should drive SuruDark and SuruGradient by setting MainView's backgroundColor, headerColor and footerColor properties.

The fix resolves the binding loops which happen when these properties are changed runtime.

[Launchpad Janitor (janitor)]

This bug was fixed in the package ubuntu-ui-toolkit - 0.1.46+14.04.20140331-0ubuntu1

---------------
ubuntu-ui-toolkit (0.1.46+14.04.20140331-0ubuntu1) trusty; urgency=low

  [ Zoltán Balogh ]
  * Separate the online and offline documentation and install the QtC
    help file

  [ Zsombor Egri ]
  * Move state data file to temp folder (LP: #1276760)
  * StateSaver does cleanup if the app is closed due to SIGTERM. This is
    needed as upstart sends this signal when the application is closed
    from app scope. SIGINT saves the state. (LP: #1259498)
  * MainView binding loop fix when backgroundColor is changed runtime.
    (LP: #1204453)

  [ Loïc Molinari ]
  * [Perf metrics] Considered number of CPU cores for CPU usage.

  [ tpeeters ]
  * Add useDeprecatedToolbar property to MainView which can be used to
    disable the current toolbar. Unsetting that property will in future
    also enable new features in the header. (LP: #1273184)
  * Close panel on contents press instead of click, so that composed
    events are not eaten by the InverseMouseArea of the Panel. (LP:
    #1295720)

  [ Christian Dywan ]
  * Treat QML warnings as fatal except for explicitly listed tests
 -- Ubuntu daily release <email address hidden> Mon, 31 Mar 2014 18:26:59 +0000