// AppStates.qml
QtObject {
     property bool workRunned: false
}
// AppWindow.qml
ApplicationWindow {
     AppStates {
          id: appStates
     }
     state: appStates.workRunned ? "run_busy_indicator" : ""
     ChildItem { appModel: appStates }
}
//ChildItem.qml
Button {
     id: child
     property AppModel appModel
     checkable: true
     Binding {
          target: appModel
          property: "workRunned"
          value: child.checked
     }
}