Rebuild a FutureBuilder

Question

I am trying to rebuild a FutureBuilder, in my case it is for the purpose of changing the camera that is shown to the user. For that I have to run the Future, the FutureBuilder uses again. The Future currently looks like this:

body: FutureBuilder(
        future: _initializeCameraControllerFuture,
        builder: (context, snapshot) {
          if (snapshot.connectionState == ConnectionState.done) {
            return CameraPreview(_cameraController);
          } else {
            return Center(child: CircularProgressIndicator());
          }
        },
      ),

The Future it is running is this one:

Future<void> _initializeCameraControllerFuture;
  @override
  void initState() {
    super.initState();

    if (camerafrontback != true) {
      _cameraController =
          CameraController(widget.camera[0], ResolutionPreset.veryHigh);
    }else{
      _cameraController =
          CameraController(widget.camera[1], ResolutionPreset.veryHigh);
    }
    _initializeCameraControllerFuture = _cameraController.initialize();
  }

I have a button that should trigger this rebuild of the FutureBuilder, it is also changing the 'camerafrontback' Boolean, so that a different camera is used. It is shown below:

IconButton(
            onPressed: () async {
              if (camerafrontback == true){
                setState(() {
                  camerafrontback = false;
                });
              }else{
                setState(() {
                  camerafrontback = true;
                });
              };

            },

At the end, before the last bracket, there must be a statement added that triggers the rebuilds of whole FutureBuilder, but I couldn't find one that suits to my code.

Thanks in advance for your answers!

Answer 1

You need to reinitialize_initializeCameraControllerFuture.

You can do it something like this

  @override
  void initState() {
    super.initState();
    _init();
  }

  ...


  _init() {
    if (camerafrontback) {
        _cameraController =
          CameraController(widget.camera[1], ResolutionPreset.veryHigh);

    } else {
         _cameraController =
          CameraController(widget.camera[0], ResolutionPreset.veryHigh);
    }
    _initializeCameraControllerFuture = _cameraController.initialize();
  }


  ...


  IconButton(
  onPressed: () async {
           if (camerafrontback) {
              camerafrontback = false;
              setState(_init());
      } else {
            camerafrontback = true;
             setState(_init);
             }
           },
         ),