Androidx Activity OnBackPressedCallback Interface Issue

Question

implementation("androidx.core:core-ktx:1.1.0-alpha04")
implementation ("androidx.appcompat:appcompat:1.0.2")
implementation ("androidx.activity:activity-ktx:1.0.0-alpha05")

I was also looking at this Why are their 2 different ComponentActivity classes? I have this library setup and hoping to use OnBackPressedCallback

import android.os.Bundle
import androidx.activity.OnBackPressedCallback
import androidx.fragment.app.Fragment

open class BaseNiceFragment : Fragment(), OnBackPressedCallback {

    override fun handleOnBackPressed(): Boolean {
       // do some nice things here
       return true
    }

    override fun onActivityCreated(savedInstanceState: Bundle?) {
       super.onActivityCreated(savedInstanceState)
       activity!!.addOnBackPressedCallback(viewLifecycleOwner, this)
    }

    override fun onDestroyView() {
       super.onDestroyView()
       activity!!.removeOnBackPressedCallback(this)
    }

    protected open fun handleEmptyView(isListEmpty: Boolean) {} 
}

It works fine with debug builds with Android Studio but whenever I try to do a app:compileFullReleaseKotlin, I keep running into the following issues

BaseNiceFragment.kt: (_, _): Unresolved reference: OnBackPressedCallback

Anyone or Ian know how to make sure this is included in all of my builds

public interface OnBackPressedCallback {
 //...
}

Exploration

You call, I answer ;) – Distressed

Answer 1

You're mixing stable releases (appcompat:1.0.2 and the fragment:1.0.0 it depends on) with alpha releases. Only Fragment 1.1.0 alpha versions of FragmentActivity depend on androidx.activity's ComponentActivity and therefore include the addOnBackPressedCallback method.

You need to specifically include androidx.fragment:fragment:1.1.0-alpha05 or switch your AppCompat dependency to androidx.appcompat:appcompat:1.1.0-alpha03 (which transitively depends on Fragment 1.1.0-alpha05).

Distressed

If this answered your question, make sure to accept the answer to remove the question from the queue of unanswered questions – Distressed

@Distressed addOnBackPressedCallback is gone in 1.1.0-alpha08. What should I use ? – Tritium

@Tritium - as per the documentation, you should use getOnBackPressedDispatcher() and the methods available on that class. – Distressed

This is so confusing... I just want to try out some of the fancy new stuff you showed at Google IO and end up trying out dependencies the whole day. In my case it was lifecycleScope which somehow needed Cancellable which somehow lead to this error after I've put in some random dependencies out of the hundreds available in the ktx cyberspace. The chosen ones can even have a -ktx suffix which may contain just the functionality you want - just try it out. – Drogheda

Answer 2

As of August 2019 this is all I needed instead of loading other dependencies as the top answer androidx.appcompat:appcompat:1.1.0-rc01

Gushy

Thanks. Finally a concise, non-confusing answer that works – Emie