In Flutter passing a callback is relatively simple. First, you need to define a function that you want to pass as a parameter. Your callback function may also receive parameter.
The above is the callback function. It's name is _callback. This function could be passed around inside another function as a parameter and it could also receive parameter inside another function. The above function takes three parameters.
Here you see how we receive callback as Function parameter. Then we also see how we are passing and calling callback. Here we are pasing three parameters.
Now let's see how we call them
This is how you actually call the _callback function. This is actually passing the _callback.