Refactors Library to work like the other recycler views.

Android/app/src/main/java/com/majinnaibu/monstercards/ui/library/LibraryFragment.java

@@ -7,6 +7,8 @@ import android.view.View;
 import android.view.ViewGroup;
 
 import androidx.annotation.NonNull;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.ViewModelProvider;
 import androidx.navigation.NavDirections;
 import androidx.navigation.Navigation;
 import androidx.recyclerview.widget.DividerItemDecoration;
@@ -18,65 +20,52 @@ import com.google.android.material.floatingactionbutton.FloatingActionButton;
 import com.google.android.material.snackbar.Snackbar;
 import com.majinnaibu.monstercards.R;
 import com.majinnaibu.monstercards.data.MonsterRepository;
+import com.majinnaibu.monstercards.databinding.FragmentLibraryBinding;
 import com.majinnaibu.monstercards.models.Monster;
 import com.majinnaibu.monstercards.ui.shared.MCFragment;
 import com.majinnaibu.monstercards.ui.shared.SwipeToDeleteCallback;
 import com.majinnaibu.monstercards.utils.Logger;
 
-import java.util.UUID;
+import java.util.List;
 
 import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers;
 import io.reactivex.rxjava3.observers.DisposableCompletableObserver;
 import io.reactivex.rxjava3.schedulers.Schedulers;
 
 public class LibraryFragment extends MCFragment {
+    private LibraryViewModel mViewModel;
+    private ViewHolder mHolder;
+    private LibraryRecyclerViewAdapter mAdapter;
 
-    public View onCreateView(@NonNull LayoutInflater inflater,
+    @Override
-                             ViewGroup container, Bundle savedInstanceState) {
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
-        View root = inflater.inflate(R.layout.fragment_library, container, false);
+        mViewModel = new ViewModelProvider(this).get(LibraryViewModel.class);
-
+        FragmentLibraryBinding binding = FragmentLibraryBinding.inflate(inflater, container, false);
-        FloatingActionButton fab = root.findViewById(R.id.fab);
+        mHolder = new ViewHolder(binding);
-        assert fab != null;
+        // TODO: set the title with setTitle(...)
-        setupAddMonsterButton(fab);
+        setupAddMonsterButton(mHolder.addButton);
-
+        setupMonsterList(mHolder.list);
-        final RecyclerView recyclerView = root.findViewById(R.id.monster_list);
+        return binding.getRoot();
-        assert recyclerView != null;
-        setupRecyclerView(recyclerView);
-
-        return root;
     }
 
-    private void setupRecyclerView(@NonNull RecyclerView recyclerView) {
+    private void setupMonsterList(@NonNull RecyclerView recyclerView) {
         Context context = requireContext();
-        MonsterRepository repository = this.getMonsterRepository();
-
-        LibraryRecyclerViewAdapter adapter = new LibraryRecyclerViewAdapter(
-                context,
-                repository.getMonsters(),
-                (monster) -> navigateToMonsterDetail(monster.id),
-                (monster) -> repository
-                        .deleteMonster(monster)
-                        .subscribeOn(Schedulers.io())
-                        .observeOn(AndroidSchedulers.mainThread())
-                        .subscribe(new DisposableCompletableObserver() {
-                            @Override
-                            public void onComplete() {
-                            }
-
-                            @Override
-                            public void onError(@io.reactivex.rxjava3.annotations.NonNull Throwable e) {
-                                Logger.logError(e);
-                            }
-                        }));
-        recyclerView.setAdapter(adapter);
-
         LinearLayoutManager layoutManager = new LinearLayoutManager(context);
         recyclerView.setLayoutManager(layoutManager);
 
+        LiveData<List<Monster>> monsterData = mViewModel.getMonsters();
+        mAdapter = new LibraryRecyclerViewAdapter(this::navigateToMonsterDetail);
+        if (monsterData != null) {
+            monsterData.observe(getViewLifecycleOwner(), monsters -> mAdapter.submitList(monsters));
+        }
+        recyclerView.setAdapter(mAdapter);
         DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(context, layoutManager.getOrientation());
         recyclerView.addItemDecoration(dividerItemDecoration);
 
-        ItemTouchHelper itemTouchHelper = new ItemTouchHelper(new SwipeToDeleteCallback(requireContext(), (position, direction) -> adapter.deleteItem(position), null));
+        ItemTouchHelper itemTouchHelper = new ItemTouchHelper(new SwipeToDeleteCallback(
+                requireContext(),
+                (position, direction) -> mViewModel.removeMonster(position),
+                null));
         itemTouchHelper.attachToRecyclerView(recyclerView);
     }
 
@@ -98,7 +87,7 @@ public class LibraryFragment extends MCFragment {
                                             view,
                                             getString(R.string.snackbar_monster_created, monster.name),
                                             Snackbar.LENGTH_LONG)
-                                            .setAction("Action", (_view) -> navigateToMonsterDetail(monster.id))
+                                            .setAction("Action", (_view) -> navigateToMonsterDetail(monster))
                                             .show();
                                 }
 
@@ -114,10 +103,22 @@ public class LibraryFragment extends MCFragment {
         });
     }
 
-    protected void navigateToMonsterDetail(UUID monsterId) {
+    protected void navigateToMonsterDetail(Monster monster) {
-        NavDirections action = LibraryFragmentDirections.actionNavigationLibraryToNavigationMonster(monsterId.toString());
+        if (monster != null) {
-        View view = getView();
+            NavDirections action = (NavDirections) LibraryFragmentDirections.actionNavigationLibraryToNavigationMonster(monster.id.toString());
-        assert view != null;
+            Navigation.findNavController(requireView()).navigate(action);
-        Navigation.findNavController(view).navigate(action);
+        } else {
+            Logger.logError("Can't navigate to MonsterDetail without a monster.");
+        }
+    }
+
+    private static class ViewHolder {
+        final FloatingActionButton addButton;
+        final RecyclerView list;
+
+        public ViewHolder(FragmentLibraryBinding binding) {
+            addButton = binding.fab;
+            list = binding.monsterList;
+        }
     }
 }

Android/app/src/main/java/com/majinnaibu/monstercards/ui/library/LibraryRecyclerViewAdapter.java

@@ -1,52 +1,35 @@
 package com.majinnaibu.monstercards.ui.library;
 
-import android.content.Context;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.TextView;
 
 import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.DiffUtil;
+import androidx.recyclerview.widget.ListAdapter;
 import androidx.recyclerview.widget.RecyclerView;
 
 import com.majinnaibu.monstercards.R;
 import com.majinnaibu.monstercards.models.Monster;
 
-import java.util.ArrayList;
+public class LibraryRecyclerViewAdapter extends ListAdapter<Monster, LibraryRecyclerViewAdapter.ViewHolder> {
-import java.util.List;
+    private static final DiffUtil.ItemCallback<Monster> DIFF_CALLBACK = new DiffUtil.ItemCallback<Monster>() {
-
-import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers;
-import io.reactivex.rxjava3.core.Flowable;
-import io.reactivex.rxjava3.disposables.Disposable;
-import io.reactivex.rxjava3.schedulers.Schedulers;
-
-public class LibraryRecyclerViewAdapter extends RecyclerView.Adapter<LibraryRecyclerViewAdapter.ViewHolder> {
-    private final Context mContext;
-    private final ItemCallback mOnDelete;
-    private final ItemCallback mOnClick;
-    private final Flowable<List<Monster>> mItemsObservable;
-    private final View.OnClickListener mOnClickListener = new View.OnClickListener() {
         @Override
-        public void onClick(@NonNull View view) {
+        public boolean areItemsTheSame(@NonNull Monster oldItem, @NonNull Monster newItem) {
-            Monster monster = (Monster) view.getTag();
+            return Monster.areItemsTheSame(oldItem, newItem);
-            if (mOnClick != null) {
+        }
-                mOnClick.onItemCallback(monster);
+
-            }
+        @Override
+        public boolean areContentsTheSame(@NonNull Monster oldItem, @NonNull Monster newItem) {
+            return Monster.areContentsTheSame(oldItem, newItem);
         }
     };
-    private List<Monster> mValues;
+    private final ItemCallback mOnClick;
-    private Disposable mDisposable;
 
-    public LibraryRecyclerViewAdapter(Context context,
+    public LibraryRecyclerViewAdapter(ItemCallback onClick) {
-                                      Flowable<List<Monster>> itemsObservable,
+        super(DIFF_CALLBACK);
-                                      ItemCallback onClick,
-                                      ItemCallback onDelete) {
-        mItemsObservable = itemsObservable;
-        mValues = new ArrayList<>();
-        mContext = context;
-        mOnDelete = onDelete;
         mOnClick = onClick;
-        mDisposable = null;
     }
 
     @Override
@@ -59,45 +42,15 @@ public class LibraryRecyclerViewAdapter extends RecyclerView.Adapter<LibraryRecy
 
     @Override
     public void onBindViewHolder(final @NonNull ViewHolder holder, int position) {
-        Monster monster = mValues.get(position);
+        Monster monster = getItem(position);
-        holder.mContentView.setText(monster.name);
+        holder.item = monster;
+        holder.contentView.setText(monster.name);
         holder.itemView.setTag(monster);
-        holder.itemView.setOnClickListener(mOnClickListener);
+        holder.itemView.setOnClickListener(v -> {
-    }
+            if (mOnClick != null) {
-
+                mOnClick.onItemCallback(holder.item);
-    @Override
+            }
-    public int getItemCount() {
+        });
-        return mValues.size();
-    }
-
-    public Context getContext() {
-        return mContext;
-    }
-
-    @Override
-    public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
-        super.onAttachedToRecyclerView(recyclerView);
-        // TODO: consider moving this subscription out of the adapter and make the subscriber call setItems on the adapter
-        mDisposable = mItemsObservable
-                .subscribeOn(Schedulers.io())
-                .observeOn(AndroidSchedulers.mainThread())
-                .subscribe(monsters -> {
-                    mValues = monsters;
-                    notifyDataSetChanged();
-                });
-    }
-
-    @Override
-    public void onDetachedFromRecyclerView(@NonNull RecyclerView recyclerView) {
-        super.onDetachedFromRecyclerView(recyclerView);
-        mDisposable.dispose();
-    }
-
-    public void deleteItem(int position) {
-        if (mOnDelete != null) {
-            Monster monster = mValues.get(position);
-            mOnDelete.onItemCallback(monster);
-        }
     }
 
     public interface ItemCallback {
@@ -105,11 +58,12 @@ public class LibraryRecyclerViewAdapter extends RecyclerView.Adapter<LibraryRecy
     }
 
     static class ViewHolder extends RecyclerView.ViewHolder {
-        final TextView mContentView;
+        final TextView contentView;
+        Monster item;
 
         ViewHolder(View view) {
             super(view);
-            mContentView = view.findViewById(R.id.content);
+            contentView = view.findViewById(R.id.content);
         }
     }
 }

Android/app/src/main/java/com/majinnaibu/monstercards/ui/library/LibraryViewModel.java

@@ -1,19 +1,74 @@
 package com.majinnaibu.monstercards.ui.library;
 
+import android.app.Application;
+
+import androidx.lifecycle.AndroidViewModel;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.MutableLiveData;
-import androidx.lifecycle.ViewModel;
 
-public class LibraryViewModel extends ViewModel {
+import com.majinnaibu.monstercards.AppDatabase;
+import com.majinnaibu.monstercards.models.Monster;
 
-    private MutableLiveData<String> mText;
+import java.util.ArrayList;
+import java.util.List;
 
-    public LibraryViewModel() {
+import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers;
-        mText = new MutableLiveData<>();
+import io.reactivex.rxjava3.annotations.NonNull;
-        mText.setValue("This is library fragment");
+import io.reactivex.rxjava3.observers.DisposableCompletableObserver;
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import io.reactivex.rxjava3.subscribers.DisposableSubscriber;
+
+public class LibraryViewModel extends AndroidViewModel {
+    private final AppDatabase mDB;
+    private final MutableLiveData<List<Monster>> mMonsters;
+
+    public LibraryViewModel(Application application) {
+        super(application);
+        mDB = AppDatabase.getInstance(application);
+        mMonsters = new MutableLiveData<>(new ArrayList<>());
+        mDB.monsterDAO()
+                .getAll()
+                .observeOn(AndroidSchedulers.mainThread())
+                .subscribeOn(Schedulers.io())
+                .subscribe(new DisposableSubscriber<List<Monster>>() {
+                    @Override
+                    public void onNext(List<Monster> monsters) {
+                        mMonsters.setValue(monsters);
+                    }
+
+                    @Override
+                    public void onError(Throwable t) {
+
+                    }
+
+                    @Override
+                    public void onComplete() {
+
+                    }
+                });
     }
 
-    public LiveData<String> getText() {
+
-        return mText;
+    public LiveData<List<Monster>> getMonsters() {
+        return mMonsters;
+    }
+
+    public void removeMonster(int position) {
+        Monster monster = mMonsters.getValue().get(position);
+        mDB.monsterDAO()
+                .delete(monster)
+                .observeOn(AndroidSchedulers.mainThread())
+                .subscribeOn(Schedulers.io())
+                .subscribe(new DisposableCompletableObserver() {
+                    @Override
+                    public void onComplete() {
+
+                    }
+
+                    @Override
+                    public void onError(@NonNull Throwable e) {
+
+                    }
+                });
     }
 }