You cannot change the wakelock with wakelockEnabled or wakelockEnabledFullscreen

[sma]

You need to implement a didUpdateWidget method similar to

  void didUpdateWidget(FlickVideoPlayer oldWidget) {
    super.didUpdateWidget(oldWidget);
    // react to a changed wakelock enablement
    if (_isFullscreen) {
      if (oldWidget.wakelockEnabledFullscreen != widget.wakelockEnabledFullscreen) {
        WakelockPlus.toggle(enable: widget.wakelockEnabledFullscreen);
      }
    } else {
      if (oldWidget.wakelockEnabled != widget.wakelockEnabled) {
        WakelockPlus.toggle(enable: widget.wakelockEnabled);
      }
    }
    // also check for a changed manager here and then call
    // _initializeFlickManager()
  }