How to add a observer for monitoring slice views changes?

Development
1

system: Windows 10
Slicer-version: 4.10.0
Hello,
I am trying to add a observer to monitor the number of slice views changes. But the right way was not found. Which node and event should be used ?
Slice views changes like this:
image
– to → image

I want to trigger my own method after the event has occurred.

Here is the method of slice views changes:

layoutManager = slicer.app.layoutManager()
      customLayout = """
                <layout type="vertical">
                <item>
                <layout type="horizontal">
                  <item splitSize="300">
                  <view class="vtkMRMLSliceNode" singletontag="Red">
                    <property name="orientation" action="default">Axial</property>
                    <property name="viewlabel" action="default">R</property>
                    <property name="viewcolor" action="default">#F34A33</property>
                  </view>
                  </item>
                  <item splitSize="300">
                  <view class="vtkMRMLSliceNode" singletontag="Red1">
                    <property name="orientation" action="default">Axial</property>
                    <property name="viewlabel" action="default">R</property>
                    <property name="viewcolor" action="default">#F34A33</property>
                  </view>
                  </item>
                </layout>
                </item>
                <item>
                <layout type="horizontal">
                  <item splitSize="300">
                    <view class="vtkMRMLSliceNode" singletontag="Red2">
                        <property name="orientation" action="default">Axial</property>
                        <property name="viewlabel" action="default">R</property>
                        <property name="viewcolor" action="default">#F34A33</property>
                    </view>
                  </item>
                  <item splitSize="300">
                    <view class="vtkMRMLSliceNode" singletontag="Red3">
                        <property name="orientation" action="default">Axial</property>
                        <property name="viewlabel" action="default">R</property>
                        <property name="viewcolor" action="default">#F34A33</property>
                    </view>
                  </item>
                </layout>
                </item>
                </layout>
                """
      # Built-in layout IDs are all below 100, so you can choose any large random number
      # for your custom layout ID.
      customLayoutId = 503

      layoutManager.layoutLogic().GetLayoutNode().AddLayoutDescription(customLayoutId, customLayout)

      # Switch to the new custom layout
      layoutManager.setLayout(customLayoutId)

customLayout = """
                        <layout type="horizontal">
                          <item splitSize="500">
                          <view class="vtkMRMLSliceNode" singletontag="Red">
                            <property name="orientation" action="default">Axial</property>
                            <property name="viewlabel" action="default">R</property>
                            <property name="viewcolor" action="default">#F34A33</property>
                          </view>
                          </item>
                          <item splitSize="500">
                          <view class="vtkMRMLSliceNode" singletontag="Red1">
                            <property name="orientation" action="default">Axial</property>
                            <property name="viewlabel" action="default">R</property>
                            <property name="viewcolor" action="default">#F34A33</property>
                          </view>
                          </item>
                        </layout>
                        """
      # Built-in layout IDs are all below 100, so you can choose any large random number
      # for your custom layout ID.
      customLayoutId = 502

      layoutManager.layoutLogic().GetLayoutNode().AddLayoutDescription(customLayoutId, customLayout)

      # Switch to the new custom layout
      layoutManager.setLayout(customLayoutId)

Thank you for your help!

2

You can add an observer to layoutManager.layoutLogic().GetLayoutNode() to get notified about layout changes.

3

Thank you so much for your support lassoan!
I used the following method(slicer.util.getNode("Layout").AddObserver(vtk.vtkCommand.ModifiedEvent, callbackFunc)) to achieve what I want. But I don’t know if there will be other problems.