Passing Constructor value from view to controller in getx

Question

So this is my view that has constructor in it. I want to pass this constructor value products to my controller i.e WishListIconController. This view is actually a widget called in many views in my current project so I pass value to it using constructor.

 class WishListIconView extends GetView{
   final products;
   final category;

   WishListIconView({this.products, this.category});
   WishListServiceApi wishListService = locator<WishListServiceApi>();

   WishlistIconController wishListIconController =
   Get.put(WishlistIconController());

  @override
  Widget build(BuildContext context) {
  return Obx(
    () => locator<SharedPreferencesManager>().isKeyExists('isLogin') == true
        ? wishListIconController.isAdded.value == false
            ? IconButton(
                splashRadius: 3,
                constraints: BoxConstraints(),
                padding: EdgeInsets.all(0),
                icon: Icon(
                  Icons.favorite_border,
                  size: 18,
                  color: Colors.blue,
                ),
                onPressed: () async {
                  bool success = await wishListService.addToWishList(
                      products.id, category, products);
                },
              )
            : IconButton(
                splashRadius: 3,
                constraints: BoxConstraints(),
                padding: EdgeInsets.all(0),
                icon: Icon(
                  Icons.favorite,
                  size: 18,
                  color: Colors.blue,
                ),
                onPressed: () async {
                  bool success = await wishListService.deleteWishListItem(
                      products.id, category);
              
                },
              )
        : IconButton(
            splashRadius: 3,
            constraints: BoxConstraints(),
            padding: EdgeInsets.all(0),
            icon: Icon(
              Icons.favorite_border,
              size: 18,
              color: Colors.blue,
            ),
            onPressed: () {
              Fluttertoast.showToast(
                  msg: "Please login to add product to wishlist",
                  toastLength: Toast.LENGTH_SHORT,
                  gravity: ToastGravity.TOP,
                  backgroundColor: Colors.blue[300],
                  textColor: Colors.white,
                  fontSize: 16.0);
            },
          ));
   }
 }

This is my controller. I want to pass product here to so I can create functions using products value.

 class WishlistIconController extends GetxController {
     WishListServiceApi wishListServiceApi = locator<WishListServiceApi>();
     var isAdded = false.obs;

   @override
  void onInit() {
    super.onInit();
    isInWishList();
  }

 isInWishList() {
   isAdded.value = wishListServiceApi.wishListResponse
    .any((element) => element.id == products.id);

  update();
 }

 @override
  void onReady() {
  super.onReady();
  isInWishList();
   }
 }

Answer 1

Here is the complete example, of nested controllers,

In first controller make Future Constructor and call your required function in it

class FirstController extends GetxController {
 
  bool? flag;

  //make a future constructor 
  Future<FirstController> init() async {
    await getFlagValue();

    //This is important
    return this;
  }

  @override
  void onInit() {
    super.onInit();
    otherFunction();
  }

  getFlagValue() async {
    //call your api here and set the value
    await Future.delayed(Duration(seconds: 1));
    flag = true;
    update();
  }

  otherFunction() async {
    print('Second Function');
  }
}

Now simply get this flag into second controller by find function.

class SecondController extends GetxController {

  //get flag value
  bool? _flagValue = Get.find<FirstController>().flag;

  @override
  void onInit() async {
    super.onInit();
    printStatus();
  }

  printStatus() {
    if(_flagValue){
       print("Flag is true");
     }else{
       print("Flag is false");
     } 
  }

}

And last but not the least the CommonBinder would change like:

class CommonBinder extends Bindings {

  //Make it async
  @override
  void dependencies() async {

    Get.put(ZeroController());
    //Use putAsync and call your future constructor in it
    await Get.putAsync<FirstController>(
        () async => await FirstController().init());
    Get.put(SecondController());
  }
}

And your main function:

return GetMaterialApp(
      title: 'Example Project',
      debugShowCheckedModeBanner: false,
      defaultTransition: Transition.size,
      initialBinding: CommonBinder(),
      home: SplashScreen(),
    );

Hope, you understand the solution