Добавил BussyIndicator

HomeForm.qml

@@ -27,4 +27,9 @@ Page {
             lights: channels
         }
     }
+
+    BusyIndicator {
+        anchors.centerIn: parent
+        running: lightsModel.isLoading
+    }
 }

LightsModel.qml

@@ -4,6 +4,7 @@ ListModel {
     id: root
 
     property string serviceUrl: undefined
+    property bool isLoading: false
 
     signal error(string text)
 
@@ -20,14 +21,18 @@ ListModel {
 
             if (request.status === 200) {
                 populateModel(JSON.parse(request.responseText))
+                root.isLoading = false
                 return
             }
 
             root.error(qsTr("[%1] Request error: %2").
                       arg(request.status).
                       arg(request.statusText))
+
+            root.isLoading = false
         }
 
+        root.isLoading = true
         request.send()
     }