How to make a function that takes both Activity and Fragment as the context for an argument-CodePudding

I have the following function that can take an activity as an argument and when I call it from an Activity it works perfectly. Now that I want to call this function from a fragment but I can see there is an error in the editor saying 'Incompatible types: CargoFragment and Activity'. I tried replacing activity: Activity with context: Context.

The error I have is at 'is CargoFragment'

    fun getProductList(activity: Activity) {
        mFireStore.collection("abc")
            .get()
            .addOnSuccessListener { 
                .....
                .....
                .....

                    productList.add(product)
                }
                when (activity) {
                    is CargoActivity -> {
                        activity.success(productList)
                    }
                    is CheckoutActivity -> {
                        activity.success(productList)
                    }
                    is CargoFragment -> {
                        activity.success(productList)
                    }
                }
            }
            .addOnFailureListener { e ->
                Log.d("CheckTag", e.message!!)
                when (activity) {
                    is CargoActivity -> {
                        activity.hideProgressDialog()
                    }
                    is CheckoutActivity -> {
                        activity.hideProgressDialog()
                    }
                }
            }
    }

CodePudding user response：

Don't pass activity to getProductList. As far as I understand, you are passing activity to execute some code when you get a response (success or failure). A better way to implement this is to expose callback lambdas.

Consider this approach:

fun getProductList(onSuccess: (List<Product>) -> Unit, onFailure:() -> Unit) {
    mFireStore.collection("abc")
            .get()
            .addOnSuccessListener {
                ...                  
                    productList.add(product)
                }
                onSuccess(productList)
            }
            .addOnFailureListener { e ->
                ...
                onFailure()
            }
}

Usage (in your activity and fragment):

getProductList(
    onSuccess = { list ->
        success(list) // whatever you want to do on success
    },
    onFailure = {
        hideProgressBar() // whatever you want to do on failure
    }
)

CodePudding user response：

if this is your viewModel, then u should NEVER have refernce to any context/activity/fragment.

Best approach would be to to have a liveData to hold progress states and let UI (activity or fragment) observe this.

CodePudding user response：

No need to change anything in function parameter. Call it from activity getProductList(this) and call it from fragment getProductList(getActivity()).