title: qt virtual keyboard does not show up
body: <p>I am trying to use the qt virtual keyboard on a raspberry pi and am having issues summoning the keyboard.</p>
  
  <p>I have configured the project as follows to allow for the use of virtual keyboard:</p>
  
  <pre><code>//In the PRO file
  QT += qml quick quickcontrols2 xml
  static {
      QT += svg
      QTPLUGIN += qtvirtualkeyboardplugin
  }
  
  CONFIG += c++11 disable-desktop
  </code></pre>
  
  <p>I think the <code>disable-desktop</code> should be enough to summon the virtual keyboard, at least that is my assumption.</p>
  
  <p>The first line in my <code>main</code> file is:</p>
  
  <pre><code>qputenv("QT_IM_MODULE", QByteArray("qtvirtualkeyboard")); 
  </code></pre>
  
  <p>This ensures that the module is loaded. I have verified that without this line, the program barfs with the virtual keyboard module not found error.</p>
  
  <p>Now, I have a simple component which has a text field as:</p>
  
  <pre><code>import QtQuick 2.0
  import QtQuick.Layouts 1.3
  import QtQuick.Controls 2.1
  import QtQuick.VirtualKeyboard 2.1
  
  TextField {
              id: idField
              width: 80
              height: 30
              placeholderText: qsTr("ID")
              Layout.maximumHeight: 30
              Layout.minimumHeight: 30
              Layout.minimumWidth: 80
              Layout.maximumWidth: 80
              focus: true
              anchors.horizontalCenter: parent.horizontalCenter
              inputMethodHints: Qt.ImhDigitsOnly
          }
  </code></pre>
  
  <p>When I click on it, the keyboard does not show up. I wonder if there is additional setup I need to do in order to summon the keyboard?</p>