android.widget.FrameLayout 不能转换为 androidx.recyclerview.widget.RecyclerView

Question

I am doing a swipe refresh function to my recycler view, but it keeps on getting an error that it cannot be cast.

Here is my XML:

announcement_recycler_view.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.swiperefreshlayout.widget.SwipeRefreshLayout
        android:id="@+id/swipeToRefresh"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/my_announcement_recycler_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:clipToPadding="false"
            android:paddingBottom="2dp"
            android:paddingTop="2dp"
            android:scrollbars="vertical"
            app:layout_behavior="@string/appbar_scrolling_view_behavior">


        </androidx.recyclerview.widget.RecyclerView>
    </androidx.swiperefreshlayout.widget.SwipeRefreshLayout>

</FrameLayout>

AnnouncementFragment

public class AnnouncementFragment extends Fragment {

    private SharedPrefManager session;
    int status_code = 0;

    //a list to store all the products
    List<Model> announcementList;

    //the recyclerview
    RecyclerView announcementRecyclerView;


    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        announcementRecyclerView = (RecyclerView) inflater.inflate(
                R.layout.announcement_recycler_view, container, false);


        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getActivity());
        announcementRecyclerView.setLayoutManager(layoutManager);

        //initializing the productlist
        announcementList = new ArrayList<>();

        // Session class instance
        session = new SharedPrefManager(getActivity());

        loadAnnouncement();

        return announcementRecyclerView;

    }


    public void loadAnnouncement(){

        final Constant WebConfig = new Constant();

        //Call our volley library
        StringRequest stringRequest = new StringRequest(Request.Method.GET, Webconfig.url,
                new Response.Listener < String > () {
                    @Override
                    public void onResponse(String response) {

                        try {
                            JSONObject obj = new JSONObject(response);
                            JSONArray details = obj.getJSONArray("data");

                            if (status_code == 200) {

                                for (int i=0; i<details.length(); i++) {

                                    JSONObject object = details.getJSONObject(i);

                                    announcementList.add(new Model(
                                            object.getInt("id"),
                                            object.getString("date"),
                                            object.getString("title"),
                                            object.getString("details"),
                                            object.getString("photo"),
                                            object.getString("content")
                                    ));

                                }
                                //creating adapter object and setting it to recyclerview
                                AnnouncementAdapter adapter = new AnnouncementAdapter(getActivity(), announcementList);
                                announcementRecyclerView.setAdapter(adapter);



                            } else {

                                Toast.makeText(getActivity(), obj.getString("error"), Toast.LENGTH_SHORT).show();

                            }

                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(getActivity(), error.getMessage(), Toast.LENGTH_SHORT).show();
                    }
                }) {

            @Override
            protected Response < String > parseNetworkResponse(NetworkResponse response) {
                status_code = response.statusCode;
                return super.parseNetworkResponse(response);
            }
        };

        VolleySingleton.getInstance(getActivity()).addToRequestQueue(stringRequest);

    }




}

how can I fix this error? I feel that by adding the swipe refresh in my XML, i need to change again my working code on the FragmentActivity , but i don't know how will i do it. any help would be really appreciated, I am still new in learning in android thats why I still don't know the proper way of doing this in Fragment .

here is the error logs

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.eplife, PID: 15045
    java.lang.ClassCastException: android.widget.FrameLayout cannot be cast to androidx.recyclerview.widget.RecyclerView
        at com.example.eplife.AnnouncementModule.AnnouncementFragment.onCreateView(AnnouncementFragment.java:48)
        at androidx.fragment.app.Fragment.performCreateView(Fragment.java:2439)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1460)
        at androidx.fragment.app.FragmentManagerImpl.addAddedFragments(FragmentManager.java:2646)
        at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2416)
        at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2372)
        at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2273)
        at androidx.fragment.app.FragmentManagerImpl$1.run(FragmentManager.java:733)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:148)
        at android.app.ActivityThread.main(ActivityThread.java:7325)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1321)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1211)

Answer 1

You are inflating a FrameLayout and casting it to RecyclerView , remove your cast and use findViewById to find your RecyclerView .

So your code should be like this:

public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    View view = inflater.inflate(
            R.layout.announcement_recycler_view, container, false);
    announcementRecyclerView = view.findViewById(R.id.my_announcement_recycler_view);

    RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getActivity());
    announcementRecyclerView.setLayoutManager(layoutManager);

    //initializing the productlist
    announcementList = new ArrayList<>();

    // Session class instance
    session = new SharedPrefManager(getActivity());

    loadAnnouncement();

    return view;
}

Answer 2

ClassCastException means that you are casting a component wrongly, ie: you are casting a TextView as an ImageView.

So, make sure that when you are initializing the recyclerView you are not using FrameLayouts ID.

In your 1st snippets the XML you provided is saying the ID of RecyclerView is my_announcement_recycler_view

But in your class you are initializing your RecyclerView like this

 announcementRecyclerView = (RecyclerView) inflater.inflate(
                R.layout.announcement_recycler_view, container, false)

which should be like this

 announcementRecyclerView = (RecyclerView) inflater.inflate(
                R.layout.my_announcement_recycler_view, container, false)