title: Qt Filesystembrowser: How to change root directory and update view
body: <p>I am trying to extend the qt filesystembrowser example (Qt-Creator -> Welcome -> Examples -> filesystembrowser). I added a button to <code>main.qml</code></p>
  
  <pre><code>Button {
      id: button
      x: 28
      y: 12
      text: qsTr("rootPath")
      onClicked: {
          view.model.setRoot("/home/myusername/test/")
          view.update()
      }
  }
  </code></pre>
  
  <p>which should change the root directory. For this, I also added the following function</p>
  
  <pre><code>Q_INVOKABLE QModelIndex setRoot(QString newPath)  {
      qInfo() &lt;&lt;"root path "&lt;&lt; this-&gt;rootPath();
      newPath.replace(0,7,"");
      setRootPath(newPath);
  }
  </code></pre>
  
  <p>After hitting the button twice, <code>qInfo</code> tells me that the root path is now <code>/home/myusername/test/</code> but the view is not updated. What am I missing here?</p>