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[Lorn Potter <lorn.potter@xxxxxxxxxxxxx>]

** Changed in: qtsystems-opensource-src (Ubuntu)
   Importance: Undecided => High

** Changed in: qtsystems-opensource-src (Ubuntu)
       Status: New => In Progress

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https://bugs.launchpad.net/bugs/1646080

Title:
  Mir-backed InputDeviceModel’s count property is not updated timely

Status in qtsystems-opensource-src package in Ubuntu:
  In Progress

Bug description:
  I’m trying to use InputDeviceModel from QML with the following
  example:

  import QtQuick 2.4
  import QtSystemInfo 5.5
  Item {
    InputDeviceModel {
      id: idm
      filter: InputInfo.Mouse
      onCountChanged: console.log("mice model count:", devices, count)
      onAdded: console.log("added mouse:", inputDevice, count)
      onRemoved: console.log("removed mouse:", deviceId, count)
    }
    readonly property bool hasMouse: idm.count > 0
    onHasMouseChanged: console.log("has mouse:", hasMouse)
  }

  When I launch the example with qmlscene on my arale with no mouse
  connected, I’m not seeing any output (expected).

  Then I connect a bluetooth keyboard/mouse combo, and I’m seeing the following:
    mice model count: 1 0
    added mouse: QInputDevice(0x17f6298) 1
    (note how 'hasMouse', which supposedly was initially false, hasn’t been updated)

  Then I disconnect the combo, and I’m seeing the following:
    mice model count: 0 1
    has mouse: true
    removed mouse: 15 0

  Then I connect it again, and I’m seeing the following:
    mice model count: 1 0
    has mouse: false
    added mouse: QInputDevice(0x18ee508) 1

  It appears the countChanged property is emitted before a device is
  added to/removed from the model, and thus the row count hasn’t
  actually been updated yet. So any property binding that relies on
  'count' will have an incorrect value.

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