How to Use Passed Parameters in Swift Setmethodcallhandler - Self.Methodname(Result: Result)

How to use passed parameters in swift setMethodCallHandler - self?.methodName(result: result)

Change your multiply method to start like this - pass call in:

private func multiply(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
  if let args = call.arguments as? Dictionary<String, Any>,
    let number = args["number"] as? Int,
    let times = args["times"] as? Int {
    // use number and times as required, for example....
    result(number * times) // or your syntax
  } else {
    result(FlutterError.init(code: "bad args", message: nil, details: nil))
  }

Are the variables inside the parentheses preceding callback functions in Flutter passed as arguments into those callback functions?

ChangeNotifierProvider(
    create: CartModel(context),
),

This is a named variable ("create") taking a CartModel as argument which has been created by given context as a constructor parameter.

ChangeNotifierProvider(
    create: (context) {
        return CartModel();
    },
),

This is a named variable ("create") taking a CartModel Function(Context) as argument. This function can be called anytime and multiple times by the ChangeNotifierProvider. When ChangeNotifierProvider are calling the method it will give a Context as argument to the method which it can use.

Update with example

Here is a small code example showing the behavior:

class A {
  B Function() createB;
  B b;

  A.callback({B Function() create}) : createB = create {
    print('Class A created');
  }

  A.value({B create}): b = create {
    print('Class A created');
  }

  void init() {
    b = createB();
  }
}

class B {
  B() {
    print('Class B created');
  }
}

void main() {
  A.value(create: B());
  // Class B created
  // Class A created

  final a = A.callback(create: () => B());
  // Class A created

  a.init();
  // Class B created
}

Why every? has '?' where as some doesnt have '?' in Clojure?

every? returns true or false, so it gets a question mark. some doesn't return a boolean, it returns "the first logically true value returned by pred", and returns nil otherwise.

Here's the lame example I came up with:

user=> (some #(if (= 0 %) 1 0)  [1 3 5 0 9])
0 

The first element in the collection gets passed into the predicate, the predicate evaluates to 0, which is logically true so some returns 0. you can see some is not returning true or false.

So every? gets a question mark because it returns true or false.
some returns the value returned by pred or nil, so it doesn't get a question mark.

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