Activity cannot be cast to LifecycleOwner

Question

My MainActivity extends AppCompatActivity

public class MainActivity extends AppCompatActivity {
private WebsiteViewModel websiteViewModel;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);


      setContentView(R.layout.activity_main);

        RecyclerView recyclerView = findViewById(R.id.recycler_view);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setHasFixedSize(true);

        final WebsiteAdapter adapter = new WebsiteAdapter();


        this.websiteViewModel = ViewModelProviders.of(this).get(WebsiteViewModel.class);

        this.websiteViewModel.getAllWebsites().observe(this, new Observer<List<Website>>() {
            @Override
            public void onChanged(@Nullable List<Website> websites) {
                adapter.setWebsites(websites);
            }
        });
        recyclerView.setAdapter(adapter);
    }
}

The error I am facing is "error: incompatible types: MainActivity cannot be converted to LifecycleOwner."

The WebsiteViewModel is

    public class WebsiteViewModel extends AndroidViewModel {
    private WebsiteRepository repository;
    private LiveData<List<Website>> allWebsites;

    public WebsiteViewModel(@NonNull Application application) {
        super(application);
        repository = new WebsiteRepository(application);
        allWebsites = repository.getAllWebsites();
    }

    public void insert(Website website) {
        repository.insert(website);
    }

    public void update(Website website) {
        repository.update(website);
    }

    public void delete(Website website) {
        repository.delete(website);
    }

    public void deleteAllWebsites() {
        repository.deleteAllWebsites();
    }

    public LiveData<List<Website>> getAllWebsites() {
        return allWebsites;
    }
}

In my other project, I am using a Fragment rather than an Activity to cast to a lifecycle owner, and that project runs without this error. However I am copying from https://codinginflow.com/tutorials/android/room-viewmodel-livedata-recyclerview-mvvm/part-6-recyclerview-adapter, but I dont know why I am having this issue. I using androidx

If I add implements LifecycleOwner in MainActivity then I get the error " java.lang.NoSuchMethodError: No super method getLifecycle()Landroidx/lifecycle/Lifecycle; in class Landroidx/core/app/ComponentActivity; or its super classes (declaration of 'androidx.core.app.ComponentActivity' appears in /data/app/com.example.project-2/split_lib_dependencies_apk.apk)"

Answer 1

Try updating your AppCompat dependency to the most recent one. I updated from 'androidx.appcompat:appcompat:1.0.0-alpha1' to 'androidx.appcompat:appcompat:1.1.0-alpha03' and it fixed it